Heat source unit and air conditioning apparatus

Abstract

The heat source unit (10) includes a first reversing valve (35) that switches between a first state in which a high-low pressure gas connection pipe (3) is connected to a discharge side of a compressor (11) and a second state in which the high-low pressure gas connection pipe (3) is connected to a suction side of the compressor (11), and a second reversing valve (36) that switches between a third state in which the discharge side of the compressor (11) is connected to a gas-side end of a first heat exchange portion (21) and the suction side of the compressor (11) is connected to a gas-side end of a second heat exchange portion (22), and a fourth state in which the discharge side of the compressor (11) is connected to the gas-side end of the second heat exchange portion (22) and the suction side of the compressor (11) is connected to the gas-side end of the first heat exchange portion (21).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a heat source unit and an air conditioning apparatus. BACKGROUND

[0002] Patent Literature 1 discloses an air conditioning apparatus that performs a cooling operation, a heating operation, and a simultaneous cooling and heating operation. As shown in Fig. 1 of Patent Literature 1, a first heat exchange portion, a second heat exchange portion, and three reversing valves are provided in a heat source unit of the air conditioning apparatus. The first reversing valve switches between a state in which a high-low pressure gas connection pipe is communicated with a suction side of a compressor and a state in which the high-low pressure gas connection pipe is communicated with a discharge side of the compressor. The second reversing valve switches between a state in which the first heat exchange portion functions as an evaporator and a state in which the first heat exchange portion functions as a radiator (condenser). The third reversing valve switches between a state in which the second heat exchange portion functions as an evaporator and a state in which the second heat exchange portion functions as a radiator (condenser). Figure 2

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2016-191502 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] As described above, the heat source unit of Patent Literature 1 has three reversing valves. Therefore, the heat source unit becomes complicated.

[0008] An object of the present disclosure is to simplify a heat source unit.

[0009] SOLUTION TO THE PROBLEMS

[0010] ​The first aspect relates to a heat source unit which is connected to a first flow path switching unit 50A and a second flow path switching unit 50B through a liquid connection pipe 2, a high / low-pressure gas connection pipe 3, and a low-pressure gas connection pipe 4, the first flow path switching unit 50A corresponding to a first utilization unit 40A, the second flow path switching unit 50B corresponding to a second utilization unit 40B, the heat source unit being provided in an air conditioning device 1 which performs a cooling operation, a heating operation, and a simultaneous cooling and heating operation, characterized by comprising a compressor 11 which compresses a refrigerant, a first heat exchanger 21 which exchanges heat between the refrigerant and air, a second heat exchanger 22 which exchanges heat between the refrigerant and the air, a liquid pipe 28 which connects a liquid side end of the first heat exchanger 21 and a liquid side end of the second heat exchanger 22, a first switching valve 35 which switches between a first state in which the high / low-pressure gas connection pipe 3 is communicated with a discharge side of the compressor 11 and a second state in which the high / low-pressure gas connection pipe 3 is communicated with a suction side of the compressor 11, and a second switching valve 36 which switches between a third state in which the discharge side of the compressor 11 is communicated with an air side end of the first heat exchanger 21 and the suction side of the compressor 11 is communicated with an air side end of the second heat exchanger 22 and a fourth state in which the discharge side of the compressor 11 is communicated with the air side end of the second heat exchanger 22 and the suction side of the compressor 11 is communicated with the air side end of the first heat exchanger 21.

[0011] In the heat source unit 10 of the first aspect, by switching of the two switching valves 35, 36, it is possible to switch between a cooling operation, a heating operation, and a simultaneous cooling and heating operation. Here, the cooling operation is an operation in which both the first utilization unit 40A and the second utilization unit 40B cool the target air. The heating operation is an operation in which both the first utilization unit 40A and the second utilization unit 40B heat the target air. The simultaneous cooling and heating operation is an operation in which a part of the first utilization unit 40A and the second utilization unit 40B cools the target air and the remaining part heats the target air.

[0012] If the first switching valve 35 becomes the second state and the second switching valve 36 becomes the third state, the air conditioning device 1 is able to perform the cooling operation. In the cooling operation, a cooling cycle is performed in which the first heat exchanger 21 functions as a radiator, the first utilization unit 40A and the second utilization unit 40B function as evaporators, and the second heat exchanger 22 functions as an evaporator.

[0013] When the first switching valve 35 becomes the first state and the second switching valve 36 becomes the fourth state, the air conditioning device 1 is capable of performing a heating operation and a simultaneous cooling and heating operation. In the heating operation, a refrigeration cycle in which the second heat exchange portion 22 functions as a radiator, the first utilization unit 40A and the second utilization unit 40B function as radiators, and the first heat exchange portion 21 functions as an evaporator is performed.

[0014] In the simultaneous cooling and heating operation, a refrigeration cycle in which the second heat exchange portion 22 functions as a radiator, one of the first utilization unit 40A and the second utilization unit 40B functions as an evaporator, the other functions as a radiator, and the first heat exchange portion 21 functions as an evaporator is performed.

[0015] In the heat source unit 10, the number of switching valves can be reduced compared to the prior art, and thus the heat source unit 10 can be simplified.

[0016] The second aspect is based on the first aspect, and the first heat exchange portion 21 is larger than the second heat exchange portion 22.

[0017] In the second aspect, in the cooling operation, the first heat exchange portion 21, which is larger in size, functions as a radiator. Thus, the amount of heat release of the refrigerant in the cooling operation can be increased. In the heating operation, the first heat exchange portion 21, which is larger in size, functions as an evaporator. Thus, the amount of heat absorption of the refrigerant in the heating operation can be increased. In the simultaneous cooling and heating operation, the first heat exchange portion 21, which is larger in size, functions as an evaporator. Thus, the amount of heat absorption of the refrigerant in the simultaneous cooling and heating operation can be increased.

[0018] The third aspect is based on the second aspect, and a ratio S2 / S1 of the size S2 of the second heat exchange portion 22 to the size S1 of the first heat exchange portion 21 is 1 / 10 or more and 1 / 5 or less.

[0019] In the third aspect, by making the ratio S2 / S1 1 / 10 or more, the size of the second heat exchange portion 22 is not made too small. By making the ratio S2 / S1 1 / 5 or less, the size of the first heat exchange portion 21 is not made too small.

[0020] The fourth aspect is based on the second or third aspect, and the second heat exchange portion 22 is arranged on the lower side of the first heat exchange portion 21.

[0021] In the fourth aspect, in the heating operation, the second heat exchange portion 22, which functions as a radiator, is located on the lower side of the first heat exchange portion 21, which functions as an evaporator. In the first heat exchange portion 21, dew may sometimes be generated along with cooling of air. The second heat exchange portion 22 suppresses freezing of the dew on the lower side of the first heat exchange portion 21 by heat release.

[0022] In the fifth aspect, the flow rate of the air flowing through the first heat exchanger 21 is likely to be greater than the flow rate of the air flowing through the second heat exchanger 22. This is because the distance between the fan 18 and the first heat exchanger 21 is shorter than the distance between the fan 18 and the second heat exchanger 22. According to this configuration, the heat release amount and the heat absorption amount of the first heat exchanger 21, which is the main heat exchanger, can be increased.

[0023] In the fifth aspect, the flow rate of the air flowing through the first heat exchanger 21 is likely to be greater than the flow rate of the air flowing through the second heat exchanger 22. This is because the distance between the fan 18 and the first heat exchanger 21 is shorter than the distance between the fan 18 and the second heat exchanger 22. According to this configuration, the heat release amount and the heat absorption amount of the first heat exchanger 21, which is the main heat exchanger, can be increased.

[0024] In the sixth aspect, the flow rate of the air flowing through the second heat exchanger 22 is likely to be greater than the flow rate of the air flowing through the first heat exchanger 21. This is because the distance between the fan 18 and the first heat exchanger 21 is shorter than the distance between the fan 18 and the second heat exchanger 22. According to this configuration, the heat release amount and the heat absorption amount of the second heat exchanger 22, which is small in size, can be increased.

[0025] In the sixth aspect, the flow rate of the air flowing through the second heat exchanger 22 is likely to be greater than the flow rate of the air flowing through the first heat exchanger 21. This is because the distance between the fan 18 and the first heat exchanger 21 is shorter than the distance between the fan 18 and the second heat exchanger 22. According to this configuration, the heat release amount and the heat absorption amount of the second heat exchanger 22, which is small in size, can be increased.

[0026] In the seventh aspect, the first heat exchanger 21 functions as a radiator in the defrosting operation. Therefore, the frost on the first heat exchanger 21 can be melted using the heat released from the first heat exchanger 21. The second heat exchanger 22 functions as an evaporator, and thus the heat absorbed from the second heat exchanger 22 can be used for defrosting of the first heat exchanger 21.

[0027] In the seventh aspect, the first heat exchanger 21 functions as a radiator in the defrosting operation. Therefore, the frost on the first heat exchanger 21 can be melted using the heat released from the first heat exchanger 21. The second heat exchanger 22 functions as an evaporator, and thus the heat absorbed from the second heat exchanger 22 can be used for defrosting of the first heat exchanger 21.

[0028] The eighth aspect relates to an air conditioning device including the heat source unit 10 of any one of the first to seventh aspects. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a piping system diagram of an air conditioning device according to an embodiment;

[0030] Figure 2This is a block diagram of the control unit and its peripheral equipment;

[0031] Figure 3 This is a simplified 3D diagram of the outdoor unit;

[0032] Figure 4 This is a simplified structural diagram of an outdoor heat exchanger;

[0033] Figure 5 This is a simplified diagram of the piping system of an air conditioning unit, which shows the flow of refrigerant during refrigeration operation.

[0034] Figure 6 This is a simplified diagram of the piping system of an air conditioning unit, which shows the flow of refrigerant during heating operation.

[0035] Figure 7 This is a simplified diagram of the piping system of an air conditioning unit, which shows the flow of refrigerant during the first operation of simultaneous cooling and heating.

[0036] Figure 8 This is a simplified diagram of the piping system of an air conditioning unit, showing the flow of refrigerant during defrost operation;

[0037] Figure 9 This is a simplified diagram of the piping system of an air conditioning unit, which shows the flow of refrigerant during the second operation of simultaneous cooling and heating.

[0038] Figure 10 This is a simplified structural diagram of the outdoor heat exchanger involved in Variation Example 1;

[0039] Figure 11 This is a simplified diagram of the piping system of the air conditioning unit involved in Variation Example 2. Detailed Implementation

[0040] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that this disclosure is not limited to the embodiments shown below, and various modifications can be made without departing from the technical concept of this disclosure. The accompanying drawings are for the purpose of briefly illustrating this disclosure; therefore, for ease of understanding, dimensions, scales, or quantities may sometimes be exaggerated or simplified as needed.

[0041] (1) Overall structure of the air conditioning unit

[0042] In this embodiment, the air conditioning unit 1 is installed in a building or similar space to regulate the temperature of the air in the target space. In this example, the target space is an indoor space R. The air conditioning unit 1 cools or heats the indoor space R.

[0043] like Figure 1 As shown, the air conditioning unit 1 includes an outdoor unit 10, multiple indoor units 40, multiple flow path switching units 50, three connecting pipes 2, 3, and 4, and a control unit C.

[0044] The outdoor unit 10 is one example of a heat source unit and is arranged outdoors. The outdoor unit 10 has a first shutoff valve 5A, a second shutoff valve 5B, and a third shutoff valve 5C.

[0045] The indoor unit 40 is one example of a utilization unit and is arranged indoors. The number of the indoor units 40 can be two or more, for example, three, four, or five or more. The air conditioning apparatus 1 of the present example includes a first indoor unit 40A as a first utilization unit and a second indoor unit 40B as a second utilization unit. The first indoor unit 40A and the second indoor unit 40B have the same basic structure. Hereinafter, the first indoor unit 40A and the second indoor unit 40B will be sometimes referred to as "indoor unit 40", respectively.

[0046] The flow path switching unit 50 is arranged corresponding to the indoor unit 40. The number of the flow path switching units 50 can be two or more, for example, three, four, or five or more. The air conditioning apparatus 1 of the present example includes a first flow path switching unit 50A and a second flow path switching unit 50B. The first flow path switching unit 50A corresponds to the first indoor unit 40A. The second flow path switching unit 50B corresponds to the second indoor unit 40B. The first flow path switching unit 50A and the second flow path switching unit 50B have the same basic structure. Hereinafter, the first flow path switching unit 50A and the second flow path switching unit 50B will be sometimes referred to as "flow path switching unit 50", respectively.

[0047] The three connection pipes are constituted by the liquid connection pipe 2, the high-low pressure gas connection pipe 3, and the low pressure gas connection pipe 4. The first flow path switching unit 50A and the second flow path switching unit 50B are connected to the outdoor unit 10 via the three connection pipes 2, 3, and 4. One end of the liquid connection pipe 2 is connected to the first shutoff valve 5A of the outdoor unit 10. One end of the high-low pressure gas connection pipe 3 is connected to the second shutoff valve 5B of the outdoor unit 10. One end of the low pressure gas connection pipe 4 is connected to the third shutoff valve 5C of the outdoor unit 10. The other end side of the liquid connection pipe 2 is branched and connected to the plurality of flow path switching units 50. The other end side of the high-low pressure gas connection pipe 3 is branched and connected to the plurality of flow path switching units 50. The other end side of the low pressure gas connection pipe 4 is branched and connected to the plurality of flow path switching units 50.

[0048] The air conditioning apparatus 1 has a refrigerant circuit 6 filled with a refrigerant. The refrigerant circuit 6 performs a vapor compression refrigeration cycle by circulating the refrigerant. The refrigerant is, for example, R32 (difluoromethane), but can be another kind of refrigerant. The refrigerant circuit 6 includes an outdoor circuit 6a as a heat source circuit provided in the outdoor unit 10, and an indoor circuit 6b as a utilization circuit provided in each indoor unit 40.

[0049] (2) Configuration elements of air conditioning apparatus

[0050] (2-1) Outdoor unit

[0051] The outdoor unit 10 has a compressor 11 and an outdoor heat exchanger 20.

[0052] The compressor 11 compresses refrigerant and discharges the compressed refrigerant. The compressor 11 is a scroll type or rotary type compressor. The outdoor unit 10 of the present example has one compressor 11, but can have two or more compressors connected in series or in parallel. The compressor 11 is a hermetic compressor having a motor. The rotation speed of the motor of the compressor 11 is variable by control of a frequency conversion device. In other words, the compressor 11 is configured so that the rotation speed (operation frequency) is variable.

[0053] The outdoor circuit 6a has a discharge pipe 12 connected to the discharge side of the compressor 11 and a suction pipe 13 connected to the suction side of the compressor 11.

[0054] The suction pipe 13 is connected to the low-pressure gas connection pipe 4 via a third stop valve 5C. A receiver 14 is provided on the suction pipe 13. The receiver 14 stores refrigerant on the suction side of the compressor 11. The receiver 14 stores liquid refrigerant and guides gaseous refrigerant to the compressor 11.

[0055] The outdoor circuit 6a has a discharge branch pipe 15, a gas relay pipe 16, and a suction branch pipe 17. The discharge branch pipe 15 is connected to an intermediate portion of the discharge pipe 12. The gas relay pipe 16 is connected to the high-low pressure gas connection pipe via a second stop valve 5B. The suction branch pipe 17 is connected to an intermediate portion of the suction pipe 13.

[0056] The outdoor heat exchanger 20 is one example of a heat source heat exchanger. The outdoor heat exchanger 20 is an air heat exchanger that exchanges heat between refrigerant and air (strictly speaking, outdoor air). The outdoor heat exchanger 20 is a fin-and-tube heat exchanger. The outdoor heat exchanger 20 has a first heat exchange portion 21 and a second heat exchange portion 22. In the present example, the first heat exchange portion 21 and the second heat exchange portion 22 are integrally provided in the outdoor heat exchanger 20.

[0057] The outdoor unit 10 has an outdoor fan 18 as a heat source fan. The outdoor fan 18 transports outdoor air. The outdoor air transported by the outdoor fan 18 passes through the outdoor heat exchanger 20. The outdoor heat exchanger 20 is a propeller fan.

[0058] The outdoor unit 10 has a first outdoor expansion valve 23, a second outdoor expansion valve 24, and a receiver 25.

[0059] The first outdoor expansion valve 23 is an example of a first heat source expansion valve. The first outdoor expansion valve 23 is installed in the outdoor circuit 6a corresponding to the first heat exchange section 21. The first outdoor expansion valve 23 reduces the pressure of the refrigerant. The first outdoor expansion valve 23 regulates the flow rate of the refrigerant. The first outdoor expansion valve 23 is composed of an electronic expansion valve whose opening degree is variable.

[0060] The second outdoor expansion valve 24 is an example of a second heat source expansion valve. The second outdoor expansion valve 24 is installed in the outdoor circuit 6a corresponding to the second heat exchange section 22. The second outdoor expansion valve 24 reduces the pressure of the refrigerant. The second outdoor expansion valve 24 regulates the flow rate of the refrigerant. The second outdoor expansion valve 24 is composed of an electronic expansion valve with a variable opening degree.

[0061] The receiver 25 is a container for storing refrigerant. Strictly speaking, the receiver 25 stores the remaining liquid refrigerant in the refrigerant circuit 6.

[0062] The outdoor circuit 6a includes a first flow path 26, a second flow path 27, and a liquid pipe 28. In the first flow path 26, a first heat exchange unit 21 and a first outdoor expansion valve 23 are arranged sequentially from its gas side end to its liquid side end. In the second flow path 27, a second heat exchange unit 22 and a second outdoor expansion valve 24 are arranged sequentially from its gas side end to its liquid side end.

[0063] One end of the liquid pipe 28 is connected to the liquid-side end of the first flow path 26 and the liquid-side end of the second flow path 27. The liquid-side end of the first heat exchange unit 21 is connected to the liquid pipe 28 via the first flow path 26. The liquid-side end of the second heat exchange unit 22 is connected to the liquid pipe 28 via the second flow path 27. The other end of the liquid pipe 28 is connected to the first shut-off valve 5A. A liquid reservoir 25 is provided on the liquid pipe 28.

[0064] Liquid conduit 28 has a first refrigerant pipe 31, a second refrigerant pipe 32, a third refrigerant pipe 33, and a fourth refrigerant pipe 34 connected in a bridge configuration. Each of these refrigerant pipes 31, 32, 33, and 34 has a check valve CV. Each check valve CV allows refrigerant to flow... Figure 1 The direction indicated by the middle arrow indicates passage, and refrigerant is prohibited from flowing in the opposite direction. The inlet end of the first refrigerant pipe 31 and the outlet end of the second refrigerant pipe 32 are connected to the liquid side ends of the first flow path 26 and the second flow path 27. The outlet end of the first refrigerant pipe 31 and the outlet end of the third refrigerant pipe 33 are connected to the inlet end of the liquid receiver 25. The inlet end of the second refrigerant pipe 32 and the inlet end of the fourth refrigerant pipe 34 are connected to the outlet end of the liquid receiver 25. The inlet end of the third refrigerant pipe 33 and the outlet end of the fourth refrigerant pipe 34 are connected to the liquid connection pipe 2 via the first shut-off valve 5A.

[0065] The outdoor unit 10 has a first four-way reversing valve 35 and a second four-way reversing valve 36. The first four-way reversing valve 35 is an example of a first reversing valve. The second four-way reversing valve 36 is an example of a second reversing valve 36.

[0066] The first four-way reversing valve 35 has a first valve port P1, a second valve port P2, a third valve port P3, and a fourth valve port P4. The first four-way reversing valve 35 uses the difference between the discharge pressure and the suction pressure to move the valve stem, thereby switching the connection state of each valve port P1, P2, P3, and P4. The first valve port P1 is connected to the discharge side of the compressor 11 via the discharge branch pipe 15. The second valve port P2 is connected to the high and low pressure gas connection pipe 3 via the gas relay pipe 16 and the second shut-off valve 5B. The third valve port P3 is connected to the suction side of the compressor 11 via the suction branch pipe 17. The fourth valve port P4 is closed by a sealing section.

[0067] The first four-way directional valve 35 is in the first state ( Figure 1 The state shown in solid lines in the middle) and the second state ( Figure 1 The system switches between states (shown by dashed lines). In the first state, the first four-way reversing valve 35 connects the first valve port P1 to the second valve port P2, and simultaneously connects the third valve port P3 to the fourth valve port P4. In other words, in the first state, the first four-way reversing valve 35 connects the high-low pressure gas connection pipe 3 to the discharge side of the compressor 11. In this state, the high-low pressure gas connection pipe 3 essentially functions as a high-pressure gas pipeline. In the second state, the first four-way reversing valve 35 connects the first valve port P1 to the fourth valve port P4, and simultaneously connects the second valve port P2 to the third valve port P3. In other words, in the second state, the second four-way reversing valve 36 connects the high-low pressure gas connection pipe 3 to the suction side of the compressor 11. In this state, the high-low pressure gas connection pipe 3 essentially functions as a low-pressure gas pipeline.

[0068] The second four-way reversing valve 36 has a fifth valve port P5, a sixth valve port P6, a seventh valve port P7, and an eighth valve port P8. The second four-way reversing valve 36 uses the difference between the discharge pressure and the suction pressure to move the valve stem, thereby switching the connection state of each valve port P5, P6, P7, and P8. The fifth valve port P5 is connected to the discharge side of the compressor 11 via the discharge pipe 12. The sixth valve port P6 is connected to the gas side of the first heat exchange section 21. The seventh valve port P7 is connected to the suction side of the compressor 11 via the suction branch pipe 17. The eighth valve port P8 is connected to the gas side of the second heat exchange section 22.

[0069] The second four-way directional valve 36 is in the third state ( Figure 1 The states shown in solid lines in the middle) and the fourth state ( Figure 1The second four-way reversing valve 36 in the third state communicates the fifth port P5 with the sixth port P6, while communicating the seventh port P7 with the eighth port P8. In other words, the second four-way reversing valve 36 in the third state communicates the discharge side of the compressor 11 with the gas-side end of the first heat exchanger 21, while communicating the suction side of the compressor 11 with the gas-side end of the second heat exchanger 22. In this state, the first heat exchanger 21 functions as a radiator, and the second heat exchanger 22 functions as an evaporator. The second four-way reversing valve 36 in the fourth state communicates the fifth port P5 with the eighth port P8, while communicating the sixth port P6 with the seventh port P7. In other words, the second four-way reversing valve 36 in the fourth state communicates the discharge side of the compressor 11 with the gas-side end of the second heat exchanger 22, while communicating the suction side of the compressor 11 with the gas-side end of the first heat exchanger 21. In this state, the second heat exchanger 22 functions as a radiator, and the first heat exchanger 21 functions as an evaporator.

[0070] (2-2) Indoor Unit

[0071] The indoor unit 40 is an air conditioning indoor unit that performs air conditioning on the indoor space R. The indoor unit 40 is, for example, a ceiling-mounted indoor unit. Here, the "ceiling-mounted" includes a manner in which the indoor unit 40 is disposed on the back surface of a ceiling, a manner in which the indoor unit 40 is embedded in the surface of a ceiling, and a manner in which the indoor unit 40 is hung on a slab or the like. In the air conditioning apparatus 1, the cooling operation and the heating operation can be selected for each of the plurality of indoor units 40. Here, the "cooling operation" is an operation in which the indoor unit 40 cools air in the target space, and the "heating operation" is an operation in which the indoor unit 40 heats air in the target space.

[0072] The indoor unit 40 has an indoor heat exchanger 41 and an indoor expansion valve 42. In the indoor circuit 6b, the indoor expansion valve 42, the indoor heat exchanger 41 are provided in this order from the liquid-side end toward the gas-side end.

[0073] The indoor heat exchanger 41 is an example of a heat exchanger. The indoor heat exchanger 41 is an air heat exchanger that exchanges heat between refrigerant and air (strictly speaking, indoor air). The indoor heat exchanger 41 is a fin-and-tube heat exchanger.

[0074] The indoor expansion valve 42 is an example of an expansion valve. The indoor expansion valve 42 depressurizes refrigerant. The indoor expansion valve 42 is constituted by an electronic expansion valve whose opening degree is variable.

[0075] The indoor unit 40 has an indoor fan 43 that uses a fan. The indoor fan 43 is, for example, a silo fan or a turbo fan. The indoor fan 43 conveys indoor air. The indoor fan 43 sucks indoor air in the indoor space R into a casing (omitted from the drawing). The air is blown out from the casing to the indoor space after passing through the indoor heat exchanger 41.

[0076] Hereinafter, the indoor heat exchanger 41 of the first indoor unit 40A is sometimes referred to as "first indoor heat exchanger 41A", the indoor heat exchanger 41 of the second indoor unit 40B is sometimes referred to as "second indoor heat exchanger 41B", the indoor expansion valve 42 of the first indoor unit 40A is sometimes referred to as "first indoor expansion valve 42A", and the indoor expansion valve 42 of the second indoor unit 40B is sometimes referred to as "second indoor expansion valve 42B".

[0077] (2-3) Flow path switching unit

[0078] The flow path switching unit 50 is provided in order to be able to perform the simultaneous operation of cooling and heating of the air conditioning device 1. The flow path switching unit 50 is, for example, provided at the back of the ceiling in the indoor. The flow path switching unit 50 switches between a state in which the liquid connection pipe 2 is communicated with the liquid side end of the indoor circuit 6b while the low-pressure gas connection pipe 4 is communicated with the gas side end of the indoor circuit 6b, and a state in which the liquid connection pipe 2 is communicated with the liquid side end of the indoor circuit 6b while the low-pressure gas connection pipe 4 is communicated with the gas side end of the indoor circuit 6b.

[0079] The flow path switching unit 50 has a first relay pipe 51, a second relay pipe 52, and a third relay pipe 53. One end of the first relay pipe 51 is connected to the liquid connection pipe 2. The other end of the first relay pipe 51 is connected to the liquid side end of the indoor circuit 6b of the indoor unit 40. One end of the second relay pipe 52 is connected to the high-low pressure gas connection pipe 3. The other end of the second relay pipe 52 is connected to the gas side end of the indoor circuit 6b of the indoor unit 40. One end of the third relay pipe 53 is connected to the low-pressure gas connection pipe 4. The other end of the third relay pipe 53 is connected to the middle of the second relay pipe 52.

[0080] The first relay valve 54 is provided on the second relay pipe 52, and the second relay valve 55 is provided on the third relay pipe 53. The first relay valve 54 is provided between the connection portion of the high-low pressure gas connection pipe 3 and the connection portion of the third relay pipe 53 on the second relay pipe 52. The first relay valve 54 is, for example, a flow regulating valve whose opening degree is variable. The first relay valve 54 can also be an on-off valve. The second relay valve 55 is, for example, a flow regulating valve whose opening degree is variable. The second relay valve 55 can also be an on-off valve.

[0081] (2-4) Control unit

[0082] Control unit C controls the operation of air conditioning unit 1 and the actions of various devices. For example... Figure 2 As shown, the control unit C includes an outdoor control unit C1 serving as a heat source control unit, multiple indoor control units C2 serving as utilization control units, multiple relay control units C3, and a remote controller 60. The outdoor control unit C1, indoor control units C2, relay control units C3, and remote controller 60 each include an MCU (Micro Control Unit), electrical circuits, and electronic circuits. The MCU includes a CPU (Central Processing Unit), memory, and a communication interface. Various programs for execution by the CPU are stored in the memory. The outdoor control unit C1, indoor control units C2, relay control units C3, and remote controller 60 are connected to each other via a wireless or wired communication line W. Figure 2 In this example, the relay control unit C3 is connected to the indoor control unit C2, but it can also be connected to the outdoor control unit C1.

[0083] The outdoor control unit C1 is located in the outdoor unit 10. The outdoor control unit C1 controls the equipment of the outdoor unit 10. Specifically, the outdoor control unit C1 controls the compressor 11, the outdoor fan 18, the first outdoor expansion valve 23, the second outdoor expansion valve 24, the first four-way reversing valve 35, and the second four-way reversing valve 36.

[0084] Indoor control units C2 are respectively installed in the first indoor unit 40A and the second indoor unit 40B. Indoor control units C2 control the equipment in the indoor units 40. Specifically, indoor control units C2 control the operation of the indoor expansion valve 42 and the indoor fan 43.

[0085] The relay control unit C3 is installed in both the first flow path switching unit 50A and the second flow path switching unit 50B. The relay control unit C3 controls the first relay valve 54 and the second relay valve 55.

[0086] The remote control 60 is correspondingly installed with the indoor unit 40. The remote control 60 is positioned within the indoor space R in a location accessible to the user. The remote control 60 has a display unit 61 and an operation unit 62. The display unit 61 is, for example, an LCD screen, displaying specified information. This specified information includes information related to the operating status of the air conditioning unit 1, information for switching the operation of the air conditioning unit 1, and information related to set values ​​such as the set temperature. The operation unit 62 accepts input operations from the user for making various settings. The operation unit 62 is, for example, composed of multiple physical switches. By operating the operation unit 62 of the remote control 60, the user can change the operating mode and set temperature of the air conditioning unit 1.

[0087] (2-5) Sensors

[0088] likeFigure 2 As shown, the air conditioning unit 1 has multiple refrigerant sensors rs and multiple air sensors as.

[0089] The multiple refrigerant sensors rs include, for example: a high-pressure sensor for detecting the high-pressure pressure of the refrigerant circuit 6, a low-pressure sensor for detecting the low-pressure pressure of the refrigerant circuit 6, a first refrigerant temperature sensor for detecting the refrigerant temperature of the first heat exchange section 21, a second refrigerant temperature sensor for detecting the refrigerant temperature of the second heat exchange section 22, an indoor refrigerant temperature sensor for detecting the refrigerant temperature of the indoor heat exchanger 41, an outlet refrigerant temperature sensor for detecting the outlet refrigerant temperature of the compressor 11, and an intake refrigerant temperature sensor for detecting the intake refrigerant temperature of the compressor 11.

[0090] Multiple air sensors include an outdoor air temperature sensor that detects the temperature of outdoor air and an indoor air temperature sensor that detects the temperature of indoor air. Strictly speaking, the indoor air temperature sensor is an intake air temperature sensor that detects the temperature of the intake air drawn into the housing of the indoor unit.

[0091] (3) Details of the outdoor unit

[0092] For outdoor unit 10, refer to Figure 3 and Figure 4 This section mainly describes the details of the outdoor heat exchanger 20 and the outdoor fan 18.

[0093] The outdoor unit 10 has an outdoor casing 10a. The outdoor casing 10a is installed, for example, on the roof of a building. The outdoor casing 10a is formed as a box with a relatively long longitudinal length. The outdoor heat exchanger 20 and the outdoor fan 18 are housed inside the outdoor casing 10a.

[0094] An outdoor heat exchanger 20 is disposed at the bottom of an outdoor housing 10a. An opening o is formed on the side of the outdoor housing 10a to expose the first heat exchange section 21 and the second heat exchange section 22 of the outdoor heat exchanger 20. The outdoor heat exchanger 20 is, for example, a three-sided heat exchanger with three sides, or a four-sided heat exchanger with four sides.

[0095] like Figure 4 As shown, the outdoor heat exchanger 20 has a first main manifold 71 and a second main manifold 72. It should be noted that... Figure 4 For ease of explanation, the multiple sides of the outdoor heat exchanger 20 are schematically represented as one side. The first main manifold 71 and the second main manifold 72 are formed as long cylindrical sections with closed upper and lower ends. The heights of the first main manifold 71 and the second main manifold are equal.

[0096] A first partition plate 73 is provided inside the first header 71. The first partition plate 73 is arranged at a lower portion of the first header 71. The first partition plate 73 divides an internal space of the first header 71 into a first upper flow path 71a and a first lower flow path 71b. The first upper flow path 71a is located at an upper side of the first partition plate 73, and the first lower flow path 71b is located at a lower side of the first partition plate 73. A first upper pipe 75a that communicates with the first upper flow path 71a and a first lower pipe 75b that communicates with the first lower flow path 71b are connected to the first header 71.

[0097] A second partition plate 74 is provided inside the second header 72. The second partition plate 74 is arranged at a lower portion of the second header 72. The second partition plate 74 is positioned at the same height position as the first partition plate 73. The second partition plate 74 divides an internal space of the second header 72 into a second upper flow path 72a and a second lower flow path 72b. The second upper flow path 72a is located at an upper side of the second partition plate 74, and the second lower flow path 72b is located at a lower side of the second partition plate 74. A second upper pipe 76a that communicates with the second upper flow path 72a and a second lower pipe 76b that communicates with the second lower flow path 72b are connected to the second header 72.

[0098] The first heat exchange portion 21 and the second heat exchange portion 22 are provided between the first header 71 and the second header 72. Specifically, in the outdoor heat exchanger 20, the first heat exchange portion 21 is formed between the first upper flow path 71a and the second upper flow path 72a. The first heat exchange portion 21 has a plurality of first heat transfer pipes 77 arranged in an up-down direction. The plurality of first heat transfer pipes 77 extend in a horizontal direction in a state of being parallel to each other. One end of the first heat transfer pipe 77 is connected to the first header 71. The one end of the first heat transfer pipe 77 communicates with the first upper flow path 71a. The other end of the first heat transfer pipe 77 is connected to the second header 72. The other end of the first heat transfer pipe 77 communicates with the second upper flow path 72a.

[0099] In the outdoor heat exchanger 20, the second heat exchange portion 22 is formed between the first lower flow path 71b and the second lower flow path 72b. The second heat exchange portion 22 has a plurality of second heat transfer pipes 78 arranged in an up-down direction. The plurality of second heat transfer pipes 78 extend in a horizontal direction in a state of being parallel to each other. One end of the second heat transfer pipe 78 is connected to the first header 71. The one end of the second heat transfer pipe 78 communicates with the first lower flow path 71b. The other end of the second heat transfer pipe 78 is connected to the second header 72. The other end of the second heat transfer pipe 78 communicates with the second lower flow path 72b.

[0100] As Figure 3As schematically shown in FIG. 1, the outdoor heat exchanger 20 has a plurality of fins 79. The fins 79 are formed in a rectangular plate shape with a longitudinal length. The fins 79 are arranged in a direction in which the first heat transfer tubes 77 and the second heat transfer tubes 78 extend. The fins 79 of the present example extend from the upper end to the lower end of the outdoor heat exchanger 20. The fins 79 serve both the first heat exchange portion 21 and the second heat exchange portion 22. In other words, the fins 79 are in contact with both the plurality of first heat transfer tubes 77 and the plurality of second heat transfer tubes 78.

[0101] The outdoor fan 18 is disposed on the upper side of the outdoor heat exchanger 20. In the outdoor unit 10 of the present example, the second heat exchange portion 22 is located on the lower side of the first heat exchange portion 21, and the outdoor fan 18 is located on the upper side of the first heat exchange portion 21.

[0102] The first heat exchange portion 21 is larger than the second heat exchange portion 22. To be precise, the outer dimensions of the first heat exchange portion 21 as a whole are larger than the outer dimensions of the second heat exchange portion 22 as a whole. The ratio S2 / S1 of the size S2 of the second heat exchange portion 22 to the size S1 of the first heat exchange portion 21 is preferably 1 / 10 or more and 1 / 5 or less.

[0103] The total heat transfer area of the first heat exchange portion 21 is larger than the total heat transfer area of the second heat exchange portion 22. The number of the first heat transfer tubes 77 of the first heat exchange portion 21 is larger than the number of the second heat transfer tubes 78 of the second heat exchange portion 22. In the present example, the diameters and lengths of the first heat transfer tubes 77 and the second heat transfer tubes 78 are equal to each other. The area of the region through which air can pass in the first heat exchange portion 21 is larger than the area of the region through which air can pass in the second heat exchange portion 22.

[0104] (4) Operation of the air conditioning device

[0105] The air conditioning device 1 performs a cooling operation, a heating operation, a simultaneous cooling and heating operation, and a defrosting operation. The cooling operation is an operation in which one indoor unit 40 in an operating state or all of the plurality of indoor units 40 in operating states perform a cooling action. The heating operation is an operation in which one indoor unit 40 in an operating state or all of the plurality of indoor units 40 in operating states perform a heating action. The simultaneous cooling and heating operation is an operation in which a part of the plurality of indoor units 40 in operating states perform a cooling action and the remaining part perform a heating action. The defrosting operation is an operation in which frost adhering to the surface of the first heat exchange portion 21 is melted in winter or the like. Hereinafter, the first indoor unit 40A and the second indoor unit 40B will be described as the indoor unit 40 in an operating state, and each operation will be described. Note that, in the drawings showing each operation, the heat exchanger functioning as a radiator is hatched with diagonal lines, and the heat exchanger functioning as an evaporator is hatched with dots.

[0106] (4-1) Cooling operation

[0107] Figure 5 The air conditioning device 1 shown in the course of the cooling operation performs a cooling cycle in which the first heat exchanging portion 21 functions as a radiator, and the second heat exchanging portion 22, the first indoor heat exchanger 41A, and the second indoor heat exchanger 41B function as evaporators.

[0108] In the cooling operation, the control portion C brings the first four-way reversing valve 35 to the second state, brings the second four-way reversing valve 36 to the third state, and adjusts the opening degrees of the second outdoor expansion valve 24, the first indoor expansion valve 42A, and the second indoor expansion valve 42B so that the refrigerant is depressurized in these valves. The control portion C opens the first outdoor expansion valve 23, the first relay valves 54, and the second relay valves 55. The control portion C operates the compressor 11, the outdoor fan 18, and the indoor fans 43.

[0109] The refrigerant that has been compressed by the compressor 11 flows into the first flow passage 26 after passing through the second four-way reversing valve 36. The refrigerant in the first flow passage 26 flows through the first heat exchanging portion 21. In the first heat exchanging portion 21, the refrigerant releases heat to the outdoor air and condenses. A part of the refrigerant that has released heat in the first heat exchanging portion 21 flows into the liquid pipe 28, and the remaining part of the refrigerant flows into the second flow passage 27.

[0110] The refrigerant in the liquid pipe 28 flows through the liquid reservoir 25 and the liquid connection pipe 2, and is divided into the first flow passage switching unit 50A and the second flow passage switching unit 50B.

[0111] The refrigerant that has flowed through the first relay pipe 51 of the first flow passage switching unit 50A is depressurized in the first indoor expansion valve 42A of the first indoor unit 40A, and flows through the first indoor heat exchanger 41A. In the first indoor heat exchanger 41A, the refrigerant absorbs heat from the indoor air and evaporates. The air that has been cooled in the first indoor heat exchanger 41A is supplied to the indoor space R. A part of the refrigerant that has evaporated in the first indoor heat exchanger 41A flows into the high-low pressure gas connection pipe 3 after passing through the second relay pipe 52 of the first flow passage switching unit 50A. The remaining part of the refrigerant that has evaporated in the first indoor heat exchanger 41A flows into the low pressure gas connection pipe 4 after passing through the third relay pipe 53 of the first flow passage switching unit 50A.

[0112] The refrigerant that has flowed through the first relay pipe 51 of the second flow path switching unit 50B is depressurized in the second indoor expansion valve 42B of the second indoor unit 40B, and then flows through the second indoor heat exchanger 41B. In the second indoor heat exchanger 41B, the refrigerant absorbs heat from indoor air and evaporates. The air that has been cooled in the second indoor heat exchanger 41B is supplied to the indoor space R. A part of the refrigerant that has evaporated in the second indoor heat exchanger 41B flows into the high-low pressure gas connection pipe 3 after passing through the second relay pipe 52 of the second flow path switching unit 50B. The refrigerant in the high-low pressure gas connection pipe 3 passes through the gas relay pipe 16 and the first four-way valve 35 in this order. The remaining part of the refrigerant that has evaporated in the second indoor heat exchanger 41B flows into the low pressure gas connection pipe 4 after passing through the third relay pipe 53 of the second flow path switching unit 50B.

[0113] As described above, the refrigerant that flows into the second flow path 27 is depressurized in the second outdoor expansion valve 24, and then flows through the second heat exchange portion 22. In the second heat exchange portion 22, the refrigerant absorbs heat from outdoor air and evaporates. The refrigerant that has evaporated in the second heat exchange portion 22 passes through the second four-way valve 36.

[0114] The refrigerant that has passed through the first four-way valve 35 and the refrigerant that has passed through the second four-way valve 36 flow through the suction branch pipe 17. The refrigerant in the low pressure gas connection pipe 4 and the refrigerant in the suction branch pipe 17 flow through the suction pipe 13. The refrigerant in the suction pipe 13 is sucked into the compressor 11 again after passing through the accumulator 14.

[0115] (4-2) Heating operation

[0116] Figure 6 The air conditioning device 1 shown in the heating operation performs a refrigeration cycle in which the second heat exchange portion 22, the first indoor heat exchanger 41A, and the second indoor heat exchanger 41B function as radiators, and the first heat exchange portion 21 functions as an evaporator.

[0117] In the heating operation, the control portion C causes the first four-way valve 35 to be in the first state, causes the second four-way valve 36 to be in the fourth state, and adjusts the opening degree of the first outdoor expansion valve 23 so that the refrigerant is depressurized therein. The control portion C opens the second outdoor expansion valve 24, the first relay valves 54, the first indoor expansion valve 42A, and the second indoor expansion valve 42B. The control portion C closes the second relay valves 55. The control portion C causes the compressor 11, the outdoor fan 18, and the indoor fans 43 to operate.

[0118] A portion of the refrigerant compressed by the compressor 11 flows through the injection branch pipe 15, and the remaining portion flows into the second flow path 27 after passing through the second four-way valve 36. The refrigerant in the injection branch pipe 15 flows through the first four-way valve 35, the gas relay pipe 16, and the high / low pressure gas connection pipe 3, and is divided into the first flow path switching unit 50A and the second flow path switching unit 50B.

[0119] The refrigerant flowing through the second relay pipe 52 of the first flow path switching unit 50A flows through the first indoor heat exchanger 41A of the first indoor unit 40A. In the first indoor heat exchanger 41A, the refrigerant releases heat to the indoor air and condenses. The air that has been heated in the first indoor heat exchanger 41A is supplied to the indoor space R. The refrigerant that has released heat in the first indoor heat exchanger 41A flows into the liquid connection pipe 2 after passing through the first relay pipe 51 of the first flow path switching unit 50A.

[0120] The refrigerant flowing through the second relay pipe 52 of the second flow path switching unit 50B flows through the second indoor heat exchanger 41B of the second indoor unit 40B. In the second indoor heat exchanger 41B, the refrigerant releases heat to the indoor air and condenses. The air that has been heated in the second indoor heat exchanger 41B is supplied to the indoor space R. The refrigerant that has released heat in the second indoor heat exchanger 41B flows into the liquid connection pipe 2 after passing through the first relay pipe 51 of the second flow path switching unit 50B.

[0121] The refrigerant in the liquid connection pipe 2 flows into the liquid pipe 28 and then passes through the accumulator 25. On the other hand, the refrigerant flowing into the second flow path 27 as described above flows through the second heat exchange portion 22. In the second heat exchange portion 22, the refrigerant releases heat to the outdoor air and condenses.

[0122] The refrigerant that has passed through the accumulator 25 and the refrigerant that has released heat in the second heat exchange portion 22 flows through the first flow path 26. The refrigerant in the first flow path 26 is depressurized by the first outdoor expansion valve 23 and then flows through the first heat exchange portion 21. In the first heat exchange portion 21, the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant that has evaporated in the first heat exchange portion 21 flows through the suction pipe 13 after passing through the second four-way valve 36 and the suction branch pipe 17. The refrigerant in the suction pipe 13 is sucked into the compressor 11 after passing through the accumulator 14 and is compressed again.

[0123] (4-3) Cooling and heating simultaneous operation

[0124] Hereinafter, an example of the cooling and heating simultaneous operation in which the first indoor unit 40A performs a cooling operation and the second indoor unit 40B performs a heating operation will be described. Figure 7The illustrated air conditioning device 1 in the simultaneous cooling and heating operation performs a cooling cycle in which the second heat exchange portion 22 and the second indoor heat exchanger 41B function as radiators, and the first heat exchange portion 21 and the first indoor heat exchanger 41A function as evaporators.

[0125] In the simultaneous cooling and heating operation, the control portion C causes the first four-way valve 35 to be in the first state, causes the second four-way valve 36 to be in the fourth state, and adjusts the opening degrees of the first outdoor expansion valve 23 and the first indoor expansion valve 42A so that the refrigerant is depressurized in the first outdoor expansion valve 23 and the first indoor expansion valve 42A. The control portion C opens the second outdoor expansion valve 24, the second relay valve 55 of the first flow switching unit 50A, the first relay valve 54 of the second flow switching unit 50B, and the second indoor expansion valve 42B. The control portion C closes the first relay valve 54 of the first flow switching unit 50A and the second relay valve 55 of the second flow switching unit 50B. The control portion C causes the compressor 11, the outdoor fan 18, and each indoor fan 43 to operate.

[0126] A portion of the refrigerant that has been compressed by the compressor 11 flows through the injection branch pipe 15, and the remaining portion flows into the second flow passage 27 after passing through the second four-way valve 36. The refrigerant in the injection branch pipe 15 flows through the first four-way valve 35, the gas relay pipe 16, and the high-low pressure gas connection pipe 3, and then flows through the second flow switching unit 50B.

[0127] The refrigerant that has flowed through the second relay pipe 52 of the second flow switching unit 50B flows through the second indoor heat exchanger 41B of the second indoor unit 40B. In the second indoor heat exchanger 41B, the refrigerant releases heat to the indoor air and condenses. The air that has been heated in the second indoor heat exchanger 41B is supplied to the indoor space R. The refrigerant that has released heat in the second indoor heat exchanger 41B flows into the liquid connection pipe 2 after passing through the first relay pipe 51 of the second flow switching unit 50B.

[0128] A portion of the refrigerant in the liquid connection pipe 2 flows into the first flow switching unit 50A. The refrigerant that has flowed through the first relay pipe 51 of the first flow switching unit 50A is depressurized in the first indoor expansion valve 42A of the first indoor unit 40A, and then flows through the first indoor heat exchanger 41A. In the first indoor heat exchanger 41A, the refrigerant absorbs heat from the indoor air and evaporates. The air that has been cooled in the first indoor heat exchanger 41A is supplied to the indoor space R. The refrigerant that has evaporated in the first indoor heat exchanger 41A flows into the low-pressure gas connection pipe 4 after passing through the third relay pipe 53 of the first flow switching unit 50A.

[0129] The remaining portion of the refrigerant in the liquid connection pipe 2 flows into the liquid pipe 28, and then passes through the reservoir 25. On the other hand, the refrigerant flowing into the second flow path 27 as described above passes through the second heat exchanging portion 22. In the second heat exchanging portion 22, the refrigerant releases heat to the outdoor air and condenses. The refrigerant passing through the reservoir 25 and the refrigerant releasing heat in the second heat exchanging portion 22 pass through the first flow path 26. The refrigerant in the first flow path 26 passes through the first heat exchanging portion 21 after being decompressed by the first outdoor expansion valve 23. In the first heat exchanging portion 21, the refrigerant absorbs heat from the outdoor air and evaporates. The refrigerant evaporated in the first heat exchanging portion 21 passes through the second four-way valve 36 and the suction branch pipe 17.

[0130] The refrigerant in the low-pressure gas connection pipe 4 and the refrigerant in the suction branch pipe 17 pass through the suction pipe 13. The refrigerant in the suction pipe 13 passes through the reservoir 14, and is then sucked into the compressor 11 to be compressed again.

[0131] (4-4) Defrost operation

[0132] In the heating operation and the simultaneous cooling and heating operation, when a prescribed condition is satisfied, the control portion C causes the air conditioning device 1 to perform the defrost operation. The prescribed condition is a condition indicating that the first heat exchanging portion 21 has frost. The prescribed condition includes, for example, the operation time of the heating operation or the simultaneous cooling and heating operation exceeding a prescribed time, a condition indicating that the evaporation capacity of the first heat exchanging portion 21 is reduced, and the like.

[0133] Figure 8 The air conditioning device 1 in the defrost operation shown performs a refrigeration cycle in which the second heat exchanging portion 22 functions as a radiator and the first heat exchanging portion 21 functions as an evaporator. In the defrost operation of the present example, the control portion C stops the operation of all the indoor units 40. Specifically, the control portion C causes the first four-way valve 35 to be in the second state, causes the second four-way valve 36 to be in the third state, adjusts the opening degree of the second outdoor expansion valve 24 so that the refrigerant is decompressed therein, and opens the first outdoor expansion valve 23. The control portion C closes the first indoor expansion valve 42A, the second indoor expansion valve 42B, the first relay valves 54, and the second relay valves 55. The control portion C causes the compressor 11 and the outdoor fan 18 to operate, and stops the indoor fans 43. In the defrost operation, the control portion C can adjust the opening degree of the first outdoor expansion valve 23 so that the refrigerant is decompressed therein.

[0134] The refrigerant, compressed by compressor 11, flows through the second four-way reversing valve 36 and then into the first flow path 26. The refrigerant in the first flow path 26 flows through the first heat exchange section 21. In the first heat exchange section 21, the refrigerant releases heat, causing the frost on the surface of the first heat exchange section 21 to melt. The refrigerant that has released heat in the first heat exchange section 21 flows into the second flow path 27, and after being depressurized in the second outdoor expansion valve 24, it flows through the second heat exchange section 22. In the second heat exchange section 22, the refrigerant absorbs heat from the outdoor air and evaporates. Therefore, the heat from the outdoor air can be used for defrosting the first heat exchange section 21. The refrigerant evaporated in the second heat exchange section 22 flows through the second four-way reversing valve 36, the suction branch pipe 17, and the suction pipe 13, and is then drawn into the compressor 11 for recompression.

[0135] (5) Flow of refrigerant in the first and second heat exchange sections

[0136] In the simultaneous heating and cooling / heating operation described above, the first heat exchange section 21 functions as an evaporator. In winter and other conditions, when outdoor air is cooled by the first heat exchange section 21, which functions as an evaporator, condensation sometimes forms in the air. This condensation falls onto the lower end of the outdoor heat exchanger 20 or the drip tray at the bottom of the casing. When this condensation freezes, ice forms at the lower end of the outdoor heat exchanger 20. If this ice gradually grows upwards, the performance of the outdoor heat exchanger 20 will be impaired. In contrast, in the simultaneous heating and cooling / heating operation of this embodiment, since the second heat exchange section 22 below the first heat exchange section 21 acts as a radiator, this ice growth can be suppressed.

[0137] Specifically, for example, in the simultaneous operation of heating and cooling / heating, Figure 4 In the outdoor heat exchanger 20 shown, low-pressure gaseous refrigerant flows into, for example, the first upper pipe 75a. This refrigerant is branched from the first upper flow path 71a to multiple first heat transfer pipes 77 of the first heat exchange section 21. The refrigerant flowing through each of the first heat transfer pipes 77 absorbs heat from the outdoor air and evaporates. The refrigerant in the multiple first heat transfer pipes 77 flows through the second upper flow path 72a and then to the second upper pipe 76a. Condensation sometimes forms on the surface of the first heat transfer pipes 77. The condensed water flows along the fins 79 to the lower end of the second heat exchange section 22.

[0138] On the other hand, high-pressure gaseous refrigerant, for example, flows into the first lower-side pipe 75b. This refrigerant is branched from the first lower-side flow path 71b to the plurality of second heat transfer pipes 78 of the second heat exchange portion 22. The refrigerant flowing through the second heat transfer pipes 78 releases heat to the outdoor air. The refrigerant flowing through the plurality of second heat transfer pipes 78 flows in the second lower-side flow path 72b, and then flows to the second lower-side pipe 76b. Since the refrigerant in the second heat exchange portion 22 releases heat, it is possible to suppress the generation of ice on the lower portion of the outdoor heat exchanger 20 or the surface of the second heat exchange portion 22. In addition, when ice is stored in the water pan on the lower side of the outdoor heat exchanger 20, it is possible to melt the ice using the heat of the second heat exchange portion 22.

[0139] Note that, in this example, the flow direction of the refrigerant flowing through each of the first heat transfer pipes 77 of the first heat exchange portion 21 is the same as the flow direction of the refrigerant flowing through each of the second heat transfer pipes 78 of the second heat exchange portion 22. However, the flow direction of the refrigerant flowing through each of the first heat transfer pipes 77 of the first heat exchange portion 21 can be opposite to the flow direction of the refrigerant flowing through each of the second heat transfer pipes 78 of the second heat exchange portion 22.

[0140] (6) Control example at the time of simultaneous cooling and heating operation

[0141] In the above simultaneous cooling and heating operation, it is also possible to switch the state of the second four-way reversing valve 36 depending on the operation state of the air-conditioning apparatus 1. Specifically, in the case where the second four-way reversing valve 36 is in the fourth state in the above simultaneous cooling and heating operation, the control portion C switches the state of the second four-way reversing valve 36 to the third state when the first condition is satisfied. By this, the air-conditioning apparatus 1 executes the second operation of the simultaneous cooling and heating operation. Figure 7 In the above simultaneous cooling and heating operation, it is also possible to switch the state of the second four-way reversing valve 36 depending on the operation state of the air-conditioning apparatus 1. Specifically, in the case where the second four-way reversing valve 36 is in the fourth state in the above simultaneous cooling and heating operation, the control portion C switches the state of the second four-way reversing valve 36 to the third state when the first condition is satisfied. By this, the air-conditioning apparatus 1 executes the second operation of the simultaneous cooling and heating operation. Figure 9 In the above simultaneous cooling and heating operation, it is also possible to switch the state of the second four-way reversing valve 36 depending on the operation state of the air-conditioning apparatus 1. Specifically, in the case where the second four-way reversing valve 36 is in the fourth state in the above simultaneous cooling and heating operation, the control portion C switches the state of the second four-way reversing valve 36 to the third state when the first condition is satisfied. By this, the air-conditioning apparatus 1 executes the second operation of the simultaneous cooling and heating operation.

[0142] In the second operation of simultaneous cooling and heating, the air conditioning apparatus 1 performs a cooling cycle in which the first heat exchanger 21 and the second indoor heat exchanger 41B function as radiators, and the second heat exchanger 22 and the first indoor heat exchanger 41A function as evaporators. The control section C controls the second outdoor expansion valve 24 to decompress the refrigerant in the second outdoor expansion valve 24. The control section C opens the first outdoor expansion valve 23 and appropriately adjusts the opening degree thereof. The control of the second operation other than this is the same as the control of the first operation.

[0143] In the second operation of simultaneous cooling and heating, a part of the refrigerant compressed in the compressor 11 releases heat in the first heat exchanger 21. This refrigerant flows through the second flow path 27 together with the refrigerant flowing out from the liquid pipe 28, and evaporates in the second heat exchanger 22. As described above, the first heat exchanger 21 functioning as a radiator is larger than the second heat exchanger 22. Therefore, in the second operation, it is possible to increase the amount of heat release of the entire refrigerant circuit 6, and it is possible to suppress excess heat of the refrigerant.

[0144] On the other hand, in the second operation of simultaneous cooling and heating, when a second condition in which the heat of the refrigerant is insufficient is satisfied, the control section C switches the second four-way reversing valve 36 from the fourth state to the third state. As a result, the air conditioning apparatus 1 performs the first operation of cooling and heating operation. As a result, the first heat exchanger 21 functions as an evaporator, and thus it is possible to eliminate the insufficient heat of the refrigerant. Here, the second condition is, for example, that the pressure of the high-pressure refrigerant or the low-pressure refrigerant is lower than a predetermined value, that the dryness of the discharged refrigerant or the suction refrigerant is less than a predetermined value, that the heating load of the utilization unit 40 in the heating operation is large, and the like.

[0145] (7) Features

[0146] (7-1)

[0147] The outdoor unit 10 of the embodiment includes a liquid pipe 28 connected to the liquid side end of the first heat exchanger 21 and the liquid side end of the second heat exchanger 22, a first four-way reversing valve 35 that is switched between a first state in which the high-low pressure gas connection pipe 3 is communicated with the discharge side of the compressor 11 and a second state in which the high-low pressure gas connection pipe 3 is communicated with the suction side of the compressor 11, and a second four-way reversing valve 36 that is switched between a third state in which the discharge side of the compressor 11 is communicated with the gas side end of the first heat exchanger 21 and the suction side of the compressor 11 is communicated with the gas side end of the second heat exchanger 22 and a fourth state in which the discharge side of the compressor 11 is communicated with the gas side end of the second heat exchanger 22 and the suction side of the compressor 11 is communicated with the gas side end of the first heat exchanger 21.

[0148] The outdoor unit 10 of the existing example has three four-way reversing valves, whereas the outdoor unit 10 of the present embodiment enables the air conditioning apparatus 1 to perform the cooling operation, the heating operation, and the simultaneous cooling and heating operation by switching the states of the two four-way reversing valves 35, 36. Thus, the simplification and cost reduction of the structure of the outdoor unit 10 can be achieved.

[0149] Further, in this configuration, in any operation, one of the first heat exchange portion 21 and the second heat exchange portion 22 functions as a radiator, and the other functions as an evaporator. Here, in a case where the air conditioning load of the air conditioning apparatus 1 greatly varies, when both the first heat exchange portion 21 and the second heat exchange portion 22 function as radiators, or both function as evaporators, a large excess of heat of the refrigerant, or a large deficiency of heat of the refrigerant can sometimes occur in association with the variation of the air conditioning load. In this case, it takes time to eliminate such an operation state, and it can be impossible to sufficiently handle the air conditioning load. In contrast, in the present embodiment, one of the first heat exchange portion 21 and the second heat exchange portion 22 functions as a radiator, and the other functions as an evaporator, and thus a large excess of heat of the refrigerant, or a large deficiency of heat of the refrigerant due to the variation of the air conditioning load of the air conditioning apparatus 1 can be suppressed. Thus, the air conditioning apparatus 1 can perform stable operation.

[0150] (7-2)

[0151] The first heat exchange portion 21 is larger than the second heat exchange portion 22. Thus, in the cooling operation, the heat release amount of the refrigerant in the first heat exchange portion 21 can be increased, and thus the cooling capacity of the indoor unit 40 can be increased. In the heating operation, the heat absorption amount (evaporation amount) of the refrigerant in the first heat exchange portion 21 can be increased, and thus the heating capacity of the indoor unit 40 can be increased. In the first action of the simultaneous cooling and heating operation, the heat absorption amount (evaporation amount) of the refrigerant in the first heat exchange portion 21 can be increased, and thus the heating capacity of the indoor unit 40 in the heating action can be increased.

[0152] (7-3)

[0153] The ratio S2 / S1 of the size S2 of the second heat exchange portion 22 to the size S1 of the first heat exchange portion 21 is 1 / 10 or more and 1 / 5 or less.

[0154] If the ratio S2 / S1 is less than 1 / 10, the second heat exchange portion 22 is too small. As a result, as described above, at the time of variation of the air conditioning load, sometimes the amount of heat of the refrigerant is excessive, or the amount of heat of the refrigerant is insufficient. In contrast, if the ratio S2 / S1 is 1 / 10 or more, the amount of heat absorption and the amount of heat emission of the second heat exchange portion 22 can be ensured. As a result, the air conditioning device 1 can perform stable operation. Further, by making the ratio S2 / S1 1 / 10 or more, the amount of heat emission of the second heat exchange portion 22 increases in the heating operation and the simultaneous cooling and heating operation. As a result, the growth of ice at the lower portion of the outdoor heat exchanger 20 can be effectively suppressed.

[0155] If the ratio S2 / S1 is more than 1 / 5, the first heat exchange portion 21 is too small. As a result, the amount of heat emission of the refrigerant in the cooling operation is insufficient, or the amount of heat absorption of the refrigerant in the heating operation and the simultaneous cooling and heating operation is insufficient. In contrast, if the ratio S2 / S1 is 1 / 5 or less, the size of the first heat exchange portion 21 can be ensured. As a result, the amount of heat emission of the refrigerant in the cooling operation can be suppressed from being insufficient, and the cooling capacity can be ensured. The amount of heat absorption of the refrigerant in the heating operation and the simultaneous cooling and heating operation can be suppressed from being insufficient, and the heating capacity can be ensured.

[0156] (7-4)

[0157] The second heat exchange portion 22 is arranged at the lower side of the first heat exchange portion 21. Therefore, in the heating operation and the simultaneous cooling and heating operation, the second heat exchange portion 22, which functions as a radiator, can suppress the growth of ice. Further, the second heat exchange portion 22 can melt ice accumulated in the water pan.

[0158] (7-5)

[0159] The outdoor fan 18 is arranged at the upper side of the first heat exchange portion 21, and transports air upward. Therefore, in the outdoor heat exchanger 20, the flow rate of air flowing through the first heat exchange portion 21 is larger than the flow rate of air flowing through the second heat exchange portion 22. This is because the outdoor fan 18 is closer to the first heat exchange portion 21 than the second heat exchange portion 22. Therefore, the amount of heat emission or the amount of heat absorption of the first heat exchange portion 21, which is the main heat exchange portion, can be increased, and thus the cooling capacity and the heating capacity can be increased.

[0160] (7-6)

[0161] The outdoor unit 10 sets the second four-way reversing valve 36 to its third state, performing defrosting operation that causes the first heat exchange section 21 to function as a radiator and the second heat exchange section 22 to function as an evaporator. During this defrosting operation, the heat absorbed in the second heat exchange section 22 can be used for defrosting the first heat exchange section 21. Furthermore, the defrosting operation allows defrosting of the first heat exchange section 21 while the refrigerant circulates only within the outdoor unit 10. Therefore, the refrigerant flow path can be shortened, reducing pressure loss. Because the refrigerant does not evaporate in the indoor unit 40, the cooling of the indoor air can be prevented.

[0162] (8) Variations

[0163] In the above embodiments, the following modified structures can also be adopted. It should be noted that the differences from the embodiments are described below.

[0164] (8-1) Variation 1

[0165] The difference between the air conditioning unit 1 in Modified Example 1 and the embodiment lies in the structure of the outdoor heat exchanger 20. For example... Figure 10 As shown, in Modified Example 1, the second heat exchange section 22 of the outdoor heat exchanger 20 is arranged above the first heat exchange section 21. A first partition 73 is disposed above the first main manifold 71, and a second partition 74 is disposed above the second main manifold 72. One end of the plurality of second heat transfer pipes 78 of the second heat exchange section 22 is connected to the first upper pipe 75a via a first upper flow path 71a. The other end of the plurality of second heat transfer pipes 78 of the second heat exchange section 22 is connected to the second upper pipe 76a via a second upper flow path 72a. The other end of the plurality of first heat transfer pipes 77 of the first heat exchange section 21 is connected to the first lower pipe 75b via a first lower flow path 71b. The other end of the plurality of first heat transfer pipes 77 of the first heat exchange section 21 is connected to the second lower pipe 76b via a second lower flow path 72b.

[0166] In Modification 1, the outdoor fan 18 is positioned above the second heat exchange section 22, directing air upwards. Therefore, in the outdoor heat exchanger 20, the airflow through the second heat exchange section 22 is greater than the airflow through the first heat exchange section 21. This is because the outdoor fan 18 is closer to the second heat exchange section 22 than the first heat exchange section 21. The second heat exchange section 22 is smaller than the first heat exchange section 21. However, by increasing the airflow in the second heat exchange section 22, the heat release and absorption of the refrigerant in the second heat exchange section 22 can be ensured.

[0167] (8-2) Variation Example 2

[0168] In variation 2, the air conditioning unit 1 adds a bypass circuit 80 to the outdoor unit 10 of the embodiment. For example...Figure 11 As shown, one end of the bypass circuit 80 is connected to the discharge side of the compressor 11 (strictly speaking, the discharge pipe 12). The other end of the bypass circuit 80 is connected to a position of the liquid pipe 28 that is on the downstream side of the reservoir 25. The diameter of the pipe that constitutes the bypass circuit 80 is the same as or smaller than the diameter of the pipe that constitutes the first flow path 26 and the diameter of the pipe that constitutes the first flow path 26. In the bypass circuit 80, a pan heater 81 and a bypass valve 82 are provided in this order from the gas side end toward the liquid side end.

[0169] The pan heater 81 is arranged on the lower side of the outdoor heat exchanger 20. In the present example, the pan heater 81 is arranged on the lower side of the second heat exchange portion 22. The pan heater 81 is provided along the bottom of the pan. The bypass valve 82 is one example of an on-off valve that opens and closes the bypass circuit 80. The bypass valve 82 is constituted by an electronic expansion valve, but can also be an electromagnetic on-off valve.

[0170] In the modification example 2, the bypass valve 82 is appropriately opened in the heating operation and the simultaneous cooling and heating operation. Thereby, a part of the refrigerant discharged from the compressor 11 flows through the pan heater 81. In the pan heater 81, the refrigerant releases heat, and thereby the ice accumulated in the pan melts. The refrigerant that has released heat in the pan heater 81 is sent to the position of the liquid pipe 28 that is on the downstream side of the reservoir 25, through the bypass valve 82. The pressure on the downstream side of the liquid pipe 28 is lower than the pressure on the upstream side thereof. Therefore, a pressure difference for causing the refrigerant to flow into the bypass circuit 80 can be ensured.

[0171] (9) Other Embodiments

[0172] In the embodiment, the first heat exchange portion 21 and the second heat exchange portion 22 are assembled in one outdoor heat exchanger 20. However, the first heat exchange portion 21 and the second heat exchange portion 22 can also be each an integral heat exchanger. In this case, the first heat exchange portion 21 constitutes a first heat source heat exchanger (first outdoor heat exchanger), and the second heat exchange portion 22 constitutes a second heat source heat exchanger (second outdoor heat exchanger).

[0173] The flow path switching unit 50 of the embodiment can also function as a blocking device that blocks the indoor circuit 6b and the three connection pipes 2, 3, 4. In this case, a valve can also be provided on the first relay pipe 51 of the flow path switching unit 50. In the case where the refrigerant leaks from the indoor unit 40 to the outside, by closing each valve of the flow path switching unit 50, the indoor circuit 6b and the three connection pipes 2, 3, 4 can be blocked. In other words, the valve of the flow path switching unit 50 functions as a blocking valve.

[0174] The first reversing valve 35 can also be a three-way valve having a first valve port P1, a second valve port P2, and a third valve port P3. In this case, the first reversing valve 35 switches between a first state in which the first valve port P1 and the second valve port P2 are communicated and a second state in which the first valve port P1 and the third valve port P3 are communicated.

[0175] The indoor unit 40 can also not be a ceiling-mounted indoor unit, but a wall-mounted or floor-standing indoor unit.

[0176] The above-described embodiments and modifications are described, but it should be understood that various changes can be made to the form and details of the embodiments without departing from the spirit and scope of the claims. The above-described embodiments, modifications, other embodiments can also be appropriately combined and replaced as long as the functions of the objects of the present disclosure are not affected.

[0177] The words "first", "second", "third", and the like described above are used only to distinguish the statements containing the words and are not intended to limit the number or order of the statements.

[0178] - Industrial applicability -

[0179] As described above, the present disclosure is useful for a heat source unit and an air conditioning apparatus.

[0180] - Symbol explanation -

[0181] 1 Air conditioning apparatus

[0182] 2 Liquid connection pipe

[0183] 3 High and low pressure gas connection pipe

[0184] 4 Low pressure gas connection pipe

[0185] 10 Heat source unit

[0186] 11 Compressor

[0187] 18 Outdoor fan (fan)

[0188] 21 First heat exchange portion

[0189] 22 Second heat exchange portion

[0190] 28 Liquid pipe

[0191] 35 First four-way reversing valve (first reversing valve)

[0192] 36 Second four-way reversing valve (second reversing valve)

[0193] 40A First indoor unit (first utilization unit)

[0194] 40B Second indoor unit (second utilization unit)

[0195] 50A First flow path switching machine unit

[0196] 50B Second flow path switching machine unit

Claims

1. A heat source unit, which is connected to a first flow path switching unit (50A) and a second flow path switching unit (50B) via a liquid connection pipe (2), a high- and low-pressure gas connection pipe (3), and a low-pressure gas connection pipe (4), wherein the first flow path switching unit (50A) corresponds to a first utilization unit (40A), and the second flow path switching unit (50B) corresponds to a second utilization unit (40B), wherein the heat source unit is installed in an air conditioning unit (1), and the air conditioning unit (1) performs cooling operation, heating operation, and simultaneous cooling and heating operation, characterized in that: The heat source unit includes a compressor (11), a first heat exchange unit (21), a second heat exchange unit (22), a liquid pipeline (28), a first reversing valve (35), and a four-way reversing valve (36). The compressor (11) compresses the refrigerant. The first heat exchange section (21) allows the refrigerant to exchange heat with the air. The second heat exchange section (22) allows the refrigerant to exchange heat with the air. The liquid pipe (28) is connected to the liquid-side end of the first heat exchange section (21) and the liquid-side end of the second heat exchange section (22). The first reversing valve (35) switches between a first state and a second state. In the first state, the high-low pressure gas connecting pipe (3) is connected to the discharge side of the compressor (11). In the second state, the high-low pressure gas connecting pipe (3) is connected to the suction side of the compressor (11). The four-way reversing valve (36) switches only between a third state and a fourth state. In the third state, the discharge side of the compressor (11) is connected to the gas side of the first heat exchange section (21), and the suction side of the compressor (11) is connected to the gas side of the second heat exchange section (22). In the fourth state, the discharge side of the compressor (11) is connected to the gas side of the second heat exchange section (22), and the suction side of the compressor (11) is connected to the gas side of the first heat exchange section (21). The heat source unit is configured such that, during the refrigeration operation, the first reversing valve (35) changes to the second state and the four-way reversing valve (36) changes to the third state, thereby performing a refrigeration cycle in which the first heat exchange unit (21) functions as a radiator and the second heat exchange unit (22) functions as an evaporator.

2. The heat source unit according to claim 1, characterized in that: The size of the first heat exchange section (21) is larger than the size of the second heat exchange section (22).

3. The heat source unit according to claim 2, characterized in that: The ratio of the size S2 of the second heat exchange section (22) to the size S1 of the first heat exchange section (21), S2 / S1, is more than 1 / 10 and less than 1 / 5.

4. The heat source unit according to claim 2, characterized in that: The second heat exchange section (22) is arranged below the first heat exchange section (21).

5. The heat source unit according to claim 4, characterized in that: The heat source unit also includes a fan (18) arranged above the second heat exchange section (22) to deliver the air that has passed through the first heat exchange section (21) and the second heat exchange section (22) upward.

6. The heat source unit according to claim 2, characterized in that: The second heat exchange section (22) is arranged below the first heat exchange section (21). The heat source unit also includes a fan (18) arranged above the first heat exchange section (21) to deliver the air that has passed through the first heat exchange section (21) and the second heat exchange section (22) upward.

7. The heat source unit according to any one of claims 1 to 6, characterized in that: The heat source unit performs defrosting operation. Under the defrosting operation, the four-way reversing valve (36) is in the third state, so that the first heat exchange section (21) functions as a radiator and the second heat exchange section (22) functions as an evaporator.

8. An air conditioning device, characterized in that: The air conditioning unit includes the heat source unit (10) as described in any one of claims 1 to 7.

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