Air conditioning system

Abstract

To recover heat.SOLUTION: An air conditioning system (1a) includes a first unit (10), a first duct (D1), a second duct (D2), a fan, and a heat transfer circuit (20). The first unit (10) has a first heat exchanger (11) that exchanges heat between water supplied from a heat source (2) and air to be sent to an indoor side. The air that has undergone heat exchange in the first heat exchanger (11) passes through the first duct (D1) and the second duct (D2). The heat transfer circuit (20) has a second heat exchanger (21) and a third heat exchanger (22), and has a heat transfer medium circulating therein. The second heat exchanger (21) exchanges heat between the water supplied from the heat source (2) and the heat transfer medium. The third heat exchanger (22) exchanges heat between the air passing through the second duct (D2) and the heat transfer medium. The air to be sent to the indoor side is heated in the third heat exchanger (22) when the air to be sent to the indoor side is cooled in the first heat exchanger (21). Alternatively, the air to be sent to the indoor side is cooled in the third heat exchanger (22) when the air to be sent to the indoor side is heated in the first heat exchanger (11).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] Regarding air conditioning systems. [Background technology]

[0002] Patent Document 1 (JP Patent Publication No. 5-33970) discloses an air conditioning system that includes an outdoor unit capable of simultaneously generating cold water and hot water, a main pipe through which the cold water circulates, a main pipe through which hot water circulates, and sub-pipes that supply cold water or hot water from each of the main pipes to an air handling unit or a fan coil unit depending on demand. Summary of the Invention [Problem to be solved by the invention]

[0003] However, in the air conditioning system of Patent Document 1 above, when cooling and heating are required simultaneously, heat recovery cannot be performed because the main pipe through which cold water circulates and the main pipe through which hot water circulates are independent. [Means for solving the problem]

[0004] The air conditioning system of a first aspect includes a first unit, a first duct, a second duct, a fan, and a heat transfer circuit. The first unit has a first heat exchanger. The first heat exchanger exchanges heat between water supplied from a heat source and air sent into a room. The first duct and the second duct are passed through by air that has undergone heat exchange in the first heat exchanger. The fan flows air from the first unit into the room. The heat transfer circuit has a second heat exchanger and a third heat exchanger. The second heat exchanger exchanges heat between the water supplied from the heat source and a heat transfer medium. The third heat exchanger exchanges heat between the air passing through the second duct and the heat transfer medium. The heat transfer circuit circulates the heat transfer medium. When the air to be sent into the room is cooled in the first heat exchanger, the air to be sent into the room is heated in the third heat exchanger, or when the air to be sent into the room is heated in the first heat exchanger, the air to be sent into the room is cooled in the third heat exchanger.

[0005] According to the air conditioning system of the first aspect, it is possible to supply air cooled or heated in the first heat exchanger to the room, and to supply air heated or cooled in the third heat exchanger to the room. Therefore, the air conditioning system is capable of mixed cooling and heating operation.

[0006] Furthermore, when air heated or cooled in the third heat exchanger is supplied indoors, the heat transfer medium is cooled or heated in the third heat exchanger, and water is cooled or heated in the second heat exchanger. Therefore, during mixed cooling and heating operation, water supplied from the heat source is heated or cooled in the first heat exchanger, and cooled or heated in the second heat exchanger, and then returned to the heat source. Therefore, the air conditioning system of the first aspect is capable of recovering heat from the water supplied from the heat source during mixed cooling and heating operation.

[0007] The air conditioning system of the second aspect is the air conditioning system of the first aspect, wherein at least a portion of the water that has passed through the first heat exchanger flows into the second heat exchanger, or at least a portion of the water that has passed through the second heat exchanger flows into the first heat exchanger.

[0008] In the air conditioning system of the second aspect, water supplied from a heat source exchanges heat with air or a heat transfer medium in the first heat exchanger or the second heat exchanger, and then further exchanges heat with a heat transfer medium or air in the second heat exchanger or the first heat exchanger, thereby enabling efficient heat recovery.

[0009] An air conditioning system according to a third aspect is the air conditioning system according to the first or second aspect, further comprising a first pipe, a second pipe, a third pipe, a fourth pipe, a first valve, a second valve, a third valve, and a fourth valve. The first pipe allows water to flow from the heat source to the first heat exchanger. The second pipe allows water to flow from the first heat exchanger to the heat source. The third pipe allows water to flow from the second pipe to the second heat exchanger. The fourth pipe allows water to flow from the second heat exchanger to a position in the second pipe between the third pipe and the heat source. The first valve is provided in the first pipe. The second valve is provided in the second pipe, between the fourth pipe and the third pipe. The third valve is provided in the third pipe. The fourth valve is provided in the fourth pipe.

[0010] In the air conditioning system of the third aspect, when the air to be sent into the room is heated in the third heat exchanger while the air to be sent into the room is cooled in the first heat exchanger, and when the air to be sent into the room is cooled in the third heat exchanger while the air to be sent into the room is heated in the first heat exchanger, the first valve can be opened to allow water supplied from the heat source to flow into the first heat exchanger via the first pipe. Then, by closing the second valve and opening the third valve, the water that has exchanged heat with the air in the first heat exchanger can be allowed to flow into the second heat exchanger via the second and third pipes. Then, by opening the fourth valve, the water that has exchanged heat with the heat carrier medium in the second heat exchanger can be returned to the heat source via the fourth and second pipes.

[0011] An air conditioning system of a fourth aspect is the air conditioning system of any one of the first aspect to the third aspect, further comprising a first pipe, a second pipe, a fifth pipe, a sixth pipe, a first valve, a second valve, a fifth valve, and a sixth valve. The first pipe allows water to flow from the heat source to the first heat exchanger. The second pipe allows water to flow from the first heat exchanger to the heat source. The fifth pipe allows water to flow from the first pipe to the second heat exchanger. The sixth pipe allows water to flow from the second heat exchanger to the first pipe. The first valve is provided in the first pipe, between the fifth pipe and the sixth pipe. The second valve is provided in the second pipe. The fifth valve is provided in the fifth pipe. The sixth valve is provided in the sixth pipe.

[0012] In the air conditioning system of the fourth aspect, when the air to be sent into the room is heated in the third heat exchanger while the air to be sent into the room is cooled in the first heat exchanger, and when the air to be sent into the room is cooled in the third heat exchanger while the air to be sent into the room is heated in the first heat exchanger, the first valve is closed and the fifth valve is opened, so that water supplied from the heat source can be made to flow into the second heat exchanger via the first and fifth pipes. Then, the sixth valve is opened, so that the water that has exchanged heat with the heat carrier medium in the second heat exchanger can be made to flow into the first heat exchanger via the sixth and first pipes. Then, the second valve is opened, so that the water that has exchanged heat with the air in the first heat exchanger can be returned to the heat source via the second pipe.

[0013] An air conditioning system according to a fifth aspect is the air conditioning system according to any one of the first aspect to the fourth aspect, further comprising a third duct. The third duct is connected to the first unit, the first duct, and the second duct. The third duct supplies air that has been heat exchanged in the first heat exchanger to the first duct and the second duct.

[0014] In the air conditioning system of the fifth aspect, it is possible to supply the air that has undergone heat exchange in the first heat exchanger to the room through the first duct and the third duct, and to supply the air to the room after exchanging heat with a heat carrying medium in the third heat exchanger through the second duct and the third duct. Therefore, it is possible to perform both cooling and heating operation with a single duct.

[0015] An air conditioning system according to a sixth aspect is the air conditioning system according to any one of the first aspect to the fifth aspect, in which the heat transfer medium is a refrigerant.

[0016] In the air conditioning system of the sixth aspect, since the refrigerant is used as the heat transport medium, the diameter of the pipes constituting the heat transport circuit can be made smaller than in the case where water is used as the heat transport medium.

[0017] An air conditioning system according to a seventh aspect is the air conditioning system according to any one of the first aspect to the sixth aspect, further comprising a control unit. The control unit controls the operation of the heat transport circuit. The control unit executes a first mode in which the heat transport circuit is used and a second mode in which the heat transport circuit is not used.

[0018] In the air conditioning system of the seventh aspect, a mixed cooling and heating operation can be easily realized by the control unit executing the first mode. Also, for example, an all-cooling operation or an all-heating operation can be realized by the control unit executing the second mode.

[0019] An air conditioning system of an eighth aspect is the air conditioning system of any one of the first aspect to the seventh aspect, further comprising a second unit. The second unit has a third heat exchanger. The second unit further has a fan and a switching member. The fan flows air into the room. The switching member switches between a mode in which air that has been heat exchanged in the first heat exchanger flows through the third heat exchanger via the second duct, and a mode in which return air from the room flows through the third heat exchanger without passing through the second duct.

[0020] In the air conditioning system of the eighth aspect, the fan and the switching member allow the air that has undergone heat exchange in the first heat exchanger or the return air from the room to flow to the third heat exchanger. This allows the air that has undergone heat exchange in the first heat exchanger or the return air to exchange heat with the heat medium in the third heat exchanger. Therefore, the air that has undergone heat exchange in the first heat exchanger or the return air can be selected according to the requirements in the room, thereby improving the thermal efficiency. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic configuration diagram of an air conditioning system according to an embodiment of the present disclosure. [Diagram 2] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a second modified example. [Diagram 3] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a second modified example. [Figure 4] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a third modified example. [Diagram 5] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a third modified example. [Figure 6] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a third modified example. [Figure 7] FIG. 11 is a schematic configuration diagram of a heat source, a first heat exchanger, and a second heat exchanger in an air conditioning system of a third modified example. [Figure 8] 13(A) and 13(B) are schematic configuration diagrams of the vicinity of the second unit in an air conditioning system of Modification 2. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An air conditioning system according to an embodiment of the present disclosure will be described with reference to the drawings.

[0023] (1) Overall structure An air conditioning system 1 according to an embodiment of the present disclosure is an apparatus used for cooling and heating a plurality of rooms in a building, etc., as shown in Fig. 1. The air conditioning system 1 is capable of both cooling and heating operation.

[0024] The air conditioning system 1a mainly comprises a heat source 2, a control unit 3, a first unit 10, a second unit 40, a third unit 30, a heat transfer circuit 20, a first pipe P1, a second pipe P2, a fourth pipe P4, a fifth pipe P5, a first duct D1, a second duct D2, a third duct D3, the first pipe P1, the second pipe P2, the fourth pipe P4, and the fifth pipe P5.

[0025] (2) Detailed configuration (2-1) Heat source The heat source 2 generates at least one of water having heat (hot water) and water having cold heat (cold water). In this embodiment, the heat source generates cold water. The heat source 2 is disposed outside the room.

[0026] (2-2) Unit 1 The first unit 10 takes in air to be sent indoors, heats or cools the taken-in air with water supplied from the heat source 2, and sends the air indoors. In this embodiment, return air RA in the indoor space is cooled with cold water supplied from the heat source 2 and sent indoors. Note that outdoor air may be taken in instead of or in addition to the return air RA.

[0027] The first unit 10 is, for example, an air handling unit. The first unit 10 includes a first heat exchanger 11 and a first fan 12.

[0028] The first heat exchanger 11 exchanges heat between the water supplied from the heat source 2 and the air sent into the room. In this embodiment, the first heat exchanger 11 cools the return air RA with cold water supplied from the heat source. Here, the first heat exchanger 11 is a cold water coil.

[0029] The first fan 12 flows air from the first unit 10 into the room. Here, the first fan 12 flows the air that has undergone heat exchange in the first heat exchanger 11 to the third unit 30 via the third duct D3 and the first duct D1, and also flows the air to the second unit 40 via the third duct D3 and the second duct D2. The first fan 12 adjusts the amount of air supplied into the room.

[0030] (2-3) 1st, 2nd, 4th and 5th pipes The first pipe P1 and the second pipe P2 connect the heat source 2 and the first unit 10. The first pipe P1 allows water to flow from the heat source 2 to the first heat exchanger 11. The second pipe P2 allows water to flow from the first heat exchanger 11 to the heat source 2.

[0031] The fourth pipe P4 allows water to flow from a second heat exchanger 21 (described later) to the second pipe P2. The fifth pipe P5 allows water to flow from the first pipe P1 to the second heat exchanger 21.

[0032] (2-4) Heat transfer circuit A heat transfer medium circulates in the heat transfer circuit 20. The heat transfer medium is not particularly limited and may be a heat medium such as water or brine, but in this embodiment, it is a refrigerant. Here, the heat transfer circuit 20 is a vapor compression type refrigerant circuit.

[0033] The heat transfer circuit 20 has a second heat exchanger 21, a third heat exchanger 22, a compressor 23, and an expansion mechanism 24. In this embodiment, the compressor 23, the third heat exchanger 22, the expansion mechanism 24, and the second heat exchanger 21 are connected in this order by piping.

[0034] The second heat exchanger 21 exchanges heat between the water supplied from the heat source 2 and the heat transfer medium. In this embodiment, the second heat exchanger 21 heats the heat transfer medium with cold water supplied from the heat source 2. Here, the second heat exchanger 21 is a direct expansion coil.

[0035] The third heat exchanger 22 exchanges heat between the air that has been heat exchanged in the first heat exchanger 11 and the heat transfer medium. In FIG. 1, the third heat exchanger 22 exchanges heat between the air passing through a third duct D3 and a second duct D2, which will be described later, and the heat transfer medium. In this embodiment, the third heat exchanger 22 heats the air that has been cooled in the first heat exchanger 11 by using a refrigerant. Here, the third heat exchanger 22 is a direct expansion coil. When the air to be sent into the room is cooled in the first heat exchanger 11, the air to be sent into the room is heated in the third heat exchanger 22.

[0036] The compressor 23 is a device for compressing the refrigerant. The expansion mechanism 24 is a mechanism for reducing the pressure of the high-pressure liquid refrigerant that has dissipated heat in the third heat exchanger 22 before being sent to the second heat exchanger 21.

[0037] (2-5) Ducts 1 to 3 The air that has undergone heat exchange in the first heat exchanger 11 passes through the first duct D1, the second duct D2, and the third duct D3.

[0038] The third duct D3 connects the first unit 10 to the first duct D1 and the second duct D2. Therefore, the air that has undergone heat exchange in the first heat exchanger 11 flows from the third duct D3 to the first duct D1 and the second duct D2. In other words, the third duct D3 supplies the air that has undergone heat exchange in the first heat exchanger 11 to the first duct D1 and the second duct D2.

[0039] The first duct D1 connects the third duct D3 and the third unit 30. The air passing through the third duct D3 flows from the first duct D1 to the third unit 30. In other words, the first duct D1 supplies the air that has been heat exchanged in the first heat exchanger 11 to the third unit 30 via the third duct D3. In further other words, the air that has been heat exchanged in the first heat exchanger 11 is supplied to the room by a single duct consisting of the first duct D1 and the third duct D3.

[0040] The second duct D2 connects the third duct D3 and the second unit 40. The air passing through the third duct D3 flows from the second duct D2 to the second unit 40. In other words, the second duct D2 supplies the air that has been heat exchanged in the first heat exchanger 11 to the second unit 40 via the third duct D3. In further other words, the air that has been heat exchanged in the first heat exchanger 11 is supplied to the room by a single duct consisting of the second duct D2 and the third duct D3.

[0041] (2-6) Third Unit The third unit 30 supplies the air that has been heat exchanged in the first heat exchanger 11 to the room. In this embodiment, the third unit 30 supplies the air that has been cooled in the first heat exchanger 11 to the room via the third duct D3 and the first duct D1. Although two third units 30 are provided in FIG. 1, three or more third units 30 may be provided, or only one third unit may be provided.

[0042] The third unit 30 has a third fan 31. The third fan 31 flows the supply air SA, which is the air that has undergone heat exchange in the first heat exchanger 11, into the room. In FIG. 1, the third fan 31 adjusts the amount of air supplied into the room.

[0043] (2-7) Control section The control unit 3 controls the devices that make up the air conditioning system 1. The control unit 3 is realized by a computer. The control unit 3 includes a control arithmetic device and a storage device. A processor such as a CPU or a GPU can be used for the control arithmetic device. The control arithmetic device reads out a program stored in the storage device, and performs predetermined image processing and arithmetic processing according to the program. Furthermore, the control arithmetic device can write the results of the calculations to the storage device and read out information stored in the storage device according to the program.

[0044] The control unit 3 of this embodiment controls the operation of the heat transport circuit 20. The control unit 3 executes a first mode in which the heat transport circuit 20 is used and a second mode in which the heat transport circuit 20 is not used. For example, the control unit 3 executes the first mode when performing a mixed cooling and heating operation, and executes the second mode when performing a full cooling operation.

[0045] Moreover, the control unit 3 in this embodiment controls the compressor 23, the first fan 12, the second fan 41, the third fan 31, and the like.

[0046] (2-8) Unit 2 The second unit 40 supplies the air that has undergone heat exchange in the first heat exchanger 11 to the room via the third heat exchanger 22. The second unit 40 has the third heat exchanger 22 and a second fan 41. Although one second unit 40 is provided in FIG. 1, two or more second units 40 may be provided.

[0047] As described above, the third heat exchanger 22 constitutes the heat transfer circuit 20. When the control unit 3 executes the first mode in which a heat transfer medium is used, the third heat exchanger 22 exchanges heat between the air from the second duct D2 and the heat transfer medium. When the control unit 3 executes the second mode in which a heat transfer medium is not used, the third heat exchanger 22 passes the air from the second duct D2 without exchanging heat with the heat transfer medium.

[0048] The second fan 41 flows the air that has passed through the third heat exchanger 22 into the room. Specifically, the second fan 41 flows the supply air SA, which is the air that has passed through the second duct D2 and the third heat exchanger 22, into the room. The second fan 41 adjusts the amount of air supplied into the room. In FIG. 1, the second fan 41 is disposed upstream of the third heat exchanger 22 in the flow of air that has undergone heat exchange in the first heat exchanger 11.

[0049] (3) Driving behavior Next, the operation of the air conditioning system 1 of this embodiment will be described. The air conditioning system 1 of this embodiment has a full cooling operation and a mixed cooling and heating operation. The operation of the air conditioning system 1 described below is performed by the control unit 3.

[0050] (3-1) Mixed cooling and heating operation A combined cooling and heating operation in which the supply air SA supplied by the third unit 30 is used to perform a cooling operation for the room, and the supply air SA supplied by the second unit 40 is used to perform a heating operation for the room will be described below.

[0051] The control unit 3 executes the first mode using the heat transport circuit 20. The control unit 3 also starts the compressor 23 to circulate the heat transport medium sealed in the heat transport circuit 20 through the third heat exchanger 22, the expansion mechanism 24, and the second heat exchanger 21 in this order.

[0052] Water having cold energy generated by the heat source 2 is supplied to the first heat exchanger 11 through the first piping P1. In the first heat exchanger 11, heat is exchanged between the water supplied from the heat source and the taken-in return air RA. The water heated in the first heat exchanger 11 returns to the heat source 2 through the second piping P2. The air cooled by the water in the first heat exchanger 11 is supplied by the first fan 12 through the third duct D3 and the first duct D1 to the third unit 30, and is also supplied through the third duct D3 and the second duct D2 to the second unit 40. In the second unit 40, this air flows to the third heat exchanger 22.

[0053] In the third unit 30, the air cooled in the first heat exchanger 11 is supplied to the room as the supply air SA by the third fan 31. This makes it possible to cool the room.

[0054] Furthermore, water having cold energy generated by the heat source 2 is supplied to the second heat exchanger 21 through the first pipe P1 and the fifth pipe P5. In the second heat exchanger 21, heat exchange is performed between the water supplied from the heat source 2 and the heat transfer medium. The water cooled in the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4 and the second pipe P2. The heat transfer medium heated in the second heat exchanger 21 flows into the compressor 23. The heat transfer medium is heated by the compressor 23 and flows into the third heat exchanger 22.

[0055] In the third heat exchanger 22, heat is exchanged between the air cooled in the first heat exchanger 11 and the heat transfer medium. The air heated by the heat transfer medium in the third heat exchanger 22 is supplied to the room as supply air SA by the second fan 41. This makes it possible to heat the room. The heat transfer medium cooled in the third heat exchanger 22 flows into the expansion mechanism 24, where it is decompressed, and flows into the second heat exchanger 21.

[0056] In this manner, in the combined cooling and heating operation of this embodiment, while the air to be sent into the room is cooled in the first heat exchanger 11, the air to be sent into the room is heated in the third heat exchanger 22.

[0057] (3-2) Full cooling operation A cooling only operation in which the supply air SA supplied by the second unit 40 and the third unit 30 is used to cool the room will be described.

[0058] The control unit 3 executes the second mode which does not use the heat transfer circuit 20. For this reason, the control unit 3 does not start the compressor 23, and does not circulate the heat medium.

[0059] In this case, in the second unit 40, the air that has been cooled by exchanging heat with water in the first heat exchanger 11 passes through the third heat exchanger 22 without exchanging heat with the heat transfer medium, and is supplied to the room as supply air SA.

[0060] In the third unit 30, similarly to the heating and cooling mixed operation, the air cooled in the first heat exchanger 11 is supplied by the third fan 31 into the room as the supply air SA.

[0061] (4) Features (4-1) The air conditioning system 1 of this embodiment includes a first unit 10, a first duct D1, a second duct D2, fans (the first fan 12, and at least one of the second fan 41 and the third fan 31), and a heat transfer circuit 20. The first unit 10 has a first heat exchanger 11. The first heat exchanger 11 exchanges heat between water supplied from a heat source 2 and air sent into a room. The first duct D1 and the second duct D2 pass air that has been heat exchanged in the first heat exchanger 11. The fan flows air from the first unit 10 into the room. The heat transfer circuit 20 has a second heat exchanger 21 and a third heat exchanger 22. The second heat exchanger 21 exchanges heat between the water supplied from the heat source 2 and a heat transfer medium. The third heat exchanger 22 exchanges heat between the air passing through the second duct D2 and the heat transfer medium. A heat transfer medium circulates through the heat transfer circuit 20. When the air to be sent into the room is cooled in the first heat exchanger 11, the air to be sent into the room is heated in the third heat exchanger 22.

[0062] According to the air conditioning system 1 of this embodiment, it is possible to supply the air cooled in the first heat exchanger 11 to the room, and to supply the air heated in the third heat exchanger 22 to the room. Therefore, the air conditioning system 1 is capable of mixed cooling and heating operation.

[0063] Furthermore, when air heated in the third heat exchanger 22 is supplied indoors, the heat transfer medium is cooled in the third heat exchanger 22, and therefore the water is cooled in the second heat exchanger 21. For this reason, during mixed cooling and heating operation, water supplied from the heat source 2 is heated in the first heat exchanger 11 and cooled in the second heat exchanger 21, and returned to the heat source 2. Therefore, the air conditioning system 1 of this embodiment is capable of recovering heat from the water supplied from the heat source 2 during mixed cooling and heating operation.

[0064] (4-2) The air conditioning system 1 of the present embodiment preferably further includes a third duct D3. The third duct D3 is connected to the first unit 10, the first duct D1, and the second duct D2. The third duct D3 supplies air that has been heat exchanged in the first heat exchanger 11 to the first duct D1 and the second duct D2.

[0065] Here, it is possible to supply the air that has undergone heat exchange in the first heat exchanger 11 to the room through the first duct D1 and the third duct D3, and to supply the air to the room through the second duct D2 and the third duct D3 after exchanging heat with a heat transfer medium in the third heat exchanger 22. Therefore, it is possible to perform both cooling and heating operation with a single duct.

[0066] (4-3) In the air conditioning system 1 of the present embodiment, the heat transfer medium is preferably a refrigerant.

[0067] In this case, since a refrigerant is used as the heat transfer medium, the diameter of the piping constituting the heat transfer circuit 20 can be made smaller than when water is used as the heat transfer medium. In addition, since water is not used as the heat transfer medium, water does not flow inside the room.

[0068] (5) Variations (5-1) Variation 1 (5-1-1) Configuration In the above embodiment, the first heat exchanger 11 is used as an example to explain how the air sent into the room is cooled by water from the heat source 2. However, in the first heat exchanger of the air conditioning system disclosed herein, the air sent into the room is at least cooled and heated by water from the heat source 2.

[0069] In this modification, the air to be sent into the room is heated by water from the heat source 2 in the first heat exchanger 11. The first heat exchanger 11 is a hot water coil.

[0070] (5-1-2) Driving behavior A description will be given of the mixed heating and cooling operation of the air conditioning system of this modified example. Note that, although the description will be made below with reference to Fig. 1, the flow of the refrigerant in the heat transport circuit 20 of this modified example is in the opposite direction to the flow of the refrigerant in the heat transport circuit 20 shown in Fig. 1.

[0071] In the first heat exchanger 11, the air to be sent into the room is heated by water having heat from the heat source 2. Then, the air heated in the first heat exchanger 11 is supplied into the room through the third duct D3, the first duct D1, and the third unit 30. This makes it possible to heat the room.

[0072] In addition, the air heated in the first heat exchanger 11 flows to the third heat exchanger 22 of the second unit 40 through the third duct D3 and the second duct D2.

[0073] The heat transfer circuit 20 is connected in the order of the compressor 23, the second heat exchanger 21, the expansion mechanism 24, and the third heat exchanger 22. The heat transfer medium discharged from the compressor 23 is cooled in the second heat exchanger 21 by heat exchange with water having warm heat from the heat source 2. The heat transfer medium is depressurized in the expansion mechanism 24 and flows to the third heat exchanger 22. In the third heat exchanger 22, the air heated in the first heat exchanger 11 is cooled by heat exchange with the heat transfer medium. This allows the room to be cooled.

[0074] (5-1-3) Features The air conditioning system of this modified example includes a first unit 10, a first duct D1, a second duct D2, fans (the first fan 12, and at least one of the second fan 41 and the third fan 31), and a heat transfer circuit 20. The first unit 10 has a first heat exchanger 11. The first heat exchanger 11 exchanges heat between water supplied from a heat source 2 and air sent into a room. The first duct D1 and the second duct D2 are passed by air that has been heat exchanged in the first heat exchanger 11. The fan flows air from the first unit 10 into the room. The heat transfer circuit 20 has a second heat exchanger 21 and a third heat exchanger 22. The second heat exchanger 21 exchanges heat between the water supplied from the heat source 2 and a heat transfer medium. The third heat exchanger 22 exchanges heat between the air passing through the second duct D2 and the heat transfer medium. A heat transfer medium circulates through the heat transfer circuit 20. When the air to be sent into the room is heated in the first heat exchanger 11, the air to be sent into the room is cooled in the third heat exchanger 22.

[0075] According to the air conditioning system 1 of this embodiment, it is possible to supply air heated in the first heat exchanger 11 to the room, and to supply air cooled in the third heat exchanger 22 to the room. Therefore, the air conditioning system of this modified example is capable of mixed cooling and heating operation.

[0076] Furthermore, when air cooled in the third heat exchanger 22 is supplied indoors, the heat transfer medium is heated in the third heat exchanger 22, and therefore the water is heated in the second heat exchanger 21. For this reason, during mixed cooling and heating operation, the water supplied from the heat source 2 is cooled in the first heat exchanger 11 and heated in the second heat exchanger 21, and then returned to the heat source 2. Therefore, the air conditioning system of this modified example is capable of recovering heat from the water supplied from the heat source 2 during mixed cooling and heating operation.

[0077] (5-2) Variation 2 (5-2-1) Configuration In the above embodiment, the first heat exchanger 11 is a cold water coil, and in the first modification, the first heat exchanger 11 is a hot water coil, but the present invention is not limited thereto. As shown in Figs. 2 and 3, the first heat exchanger 11 in this modification is a cold / hot water coil that serves as a cold water coil and a hot water coil. In addition, in this modification, a mixed cooling and heating operation is possible in which the air to be sent into the room is heated in the third heat exchanger 22 when the air to be sent into the room is cooled in the first heat exchanger 11, and a mixed cooling and heating operation is possible in which the air to be sent into the room is cooled in the third heat exchanger 22 when the air to be sent into the room is heated in the first heat exchanger 11.

[0078] In addition, the air conditioning system 1b of this modified example further includes a third pipe P3, a sixth pipe P6, a first valve V1, a second valve V2, a third valve V3, a fourth valve V4, a fifth valve V5, and a sixth valve V6.

[0079] The third pipe P3 allows water to flow from the second pipe P2 to the second heat exchanger 21. The fourth pipe P4 of this modification allows water to flow from the second heat exchanger 21 to a portion of the second pipe P2 between the third pipe P3 and the heat source 2. The sixth pipe P6 allows water to flow from the second heat exchanger 21 to the first pipe P1.

[0080] The first valve V1 is provided in the first pipe P1. Here, the first valve V1 is provided in the first pipe P1 between the fifth pipe P5 and the sixth pipe P6. The second valve V2 is provided in the second pipe P2 between the fourth pipe P4 and the third pipe P3. The third valve V3 is provided in the third pipe P3. The fourth valve V4 is provided in the fourth pipe P4. The fifth valve V5 is provided in the fifth pipe P5. The sixth valve V6 is provided in the sixth pipe P6.

[0081] In addition, the heat transfer circuit 20 further has a switching mechanism (not shown) that switches between circulating the heat transfer medium through the compressor 23, the third heat exchanger 22, the expansion mechanism 24, and the second heat exchanger 21 in that order, and circulating the heat transfer medium through the compressor 23, the second heat exchanger 21, the expansion mechanism 24, and the third heat exchanger 22 in that order.

[0082] The control unit 3 of this modified example further controls the opening degrees of the first valve V1 to the sixth valve V6, the switching mechanism of the heat transport circuit 20, and the like.

[0083] (5-2-2) Driving behavior Hereinafter, the mixed cooling and heating operation of the air conditioning system 1b of this modified example will be described. Note that the air conditioning system 1b is also capable of full cooling operation and full heating operation.

[0084] (5-2-2-1) 1st Cooling and Heating Mixed Operation The first mixed cooling and heating operation in which the first heat exchanger 11 is used as a chilled water coil will be described with reference to Fig. 2. In the first mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform indoor cooling operation, and the second unit 40 supplies the supply air SA to perform indoor heating operation.

[0085] The control unit 3 performs control so as to open the first valve V1, the third valve V3, and the fourth valve V4, and close the second valve V2, the fifth valve V5, and the sixth valve V6.

[0086] Cold water from the heat source 2 flows through the first pipe P1 to the first heat exchanger 11. The water that has exchanged heat with the air to be sent into the room in the first heat exchanger 11 flows through the second pipe P2, the third pipe P3, and the fifth pipe P5 to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4 and the second pipe P2.

[0087] In the first cooling / heating mixed operation, water that has been heated by heat exchange with air in the first heat exchanger 11 is caused to flow into the second heat exchanger 21, where the heat transfer medium is heated.

[0088] (5-2-2-2) Second cooling and heating mixed operation In the first cooling / heating mixed operation, when the amount of water flowing into the second heat exchanger 21 is insufficient, the control unit 3 slightly opens the fifth valve V5. As a result, in addition to the water that has passed through the first heat exchanger 11, the water from the heat source 2 before flowing into the first heat exchanger 11 flows into the second heat exchanger 21 through the fifth pipe P5.

[0089] (5-2-2-3) 3rd Heating and Cooling Mixed Operation The third mixed cooling and heating operation in which the first heat exchanger 11 is used as a chilled water coil will be described with reference to Fig. 3. In the third mixed cooling and heating operation, the supply air SA supplied by the third unit 43 is used for cooling the room, and the supply air SA supplied by the second unit 40 is used for heating the room.

[0090] The control unit 3 performs control so as to open the second valve V2, the fifth valve V5, and the sixth valve V6, and close the first valve V1, the third valve V3, and the fourth valve V4.

[0091] The medium-temperature water from the heat source 2 flows through the first pipe P1 and the fifth pipe P5 to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 flows through the fourth pipe P4, the sixth pipe P6, and the first pipe P1 to the first heat exchanger 11. The water that has exchanged heat with the air in the first heat exchanger 11 returns to the heat source 2 through the second pipe P2.

[0092] In the third combined cooling and heating operation, the water cooled by heat exchange with the heat transfer medium in the second heat exchanger 21 is caused to flow through the first heat exchanger 11, where the air is cooled.

[0093] (5-2-2-4) 4th Cooling and Heating Mixed Operation In the third mixed cooling and heating operation, when the amount of water flowing into the first heat exchanger 11 is large, the control unit 3 slightly opens the fourth valve V4. As a result, a part of the water that has passed through the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4 and the second pipe P2 without flowing into the first heat exchanger 11.

[0094] (5-2-2-5) 5th Cooling and Heating Mixed Operation 2, a fifth mixed cooling and heating operation in which the first heat exchanger 11 is used as a hot water coil will be described. In the fifth mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform a heating operation in the room, and the second unit 40 supplies the supply air SA to perform a cooling operation in the room.

[0095] The control unit 3 performs control so as to open the first valve V1, the third valve V3, and the fourth valve V4, and close the second valve V2, the fifth valve V5, and the sixth valve V6.

[0096] Hot water from the heat source 2 flows through the first pipe P1 to the first heat exchanger 11. The water that has exchanged heat with the air to be sent into the room in the first heat exchanger 11 flows through the second pipe P2, the third pipe P3, and the fifth pipe P5 to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4 and the second pipe P2.

[0097] In the fifth mixed cooling / heating operation, the water cooled by heat exchange with the air in the first heat exchanger 11 is caused to flow into the second heat exchanger 21, where the heat transfer medium is cooled.

[0098] (5-2-2-6) 6th Cooling and Heating Mixed Operation In the fifth cooling / heating mixed operation, when the amount of water flowing into the second heat exchanger 21 is insufficient, the control unit 3 slightly opens the fifth valve V5. As a result, in addition to the water that has passed through the first heat exchanger 11, the water from the heat source 2 before flowing into the first heat exchanger 11 flows into the second heat exchanger 21 through the fifth pipe P5.

[0099] (5-2-2-7) 7th cooling and heating mixed operation A seventh mixed cooling and heating operation in which the first heat exchanger 11 is used as a hot water coil will be described with reference to Fig. 3. In the seventh mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform a heating operation in the room, and the second unit 40 supplies the supply air SA to perform a cooling operation in the room.

[0100] The control unit 3 performs control so as to open the second valve V2, the fifth valve V5, and the sixth valve V6, and close the first valve V1, the third valve V3, and the fourth valve V4.

[0101] The medium-temperature water from the heat source 2 flows through the first pipe P1 and the fifth pipe P5 to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 flows through the fourth pipe P4, the sixth pipe P6, and the first pipe P1 to the first heat exchanger 11. The water that has exchanged heat with the air in the first heat exchanger 11 returns to the heat source 2 through the second pipe P2.

[0102] In the seventh cooling / heating mixed operation, the water heated by heat exchange with the heat transfer medium in the second heat exchanger 21 is caused to flow into the first heat exchanger 11, where the air is heated.

[0103] (5-2-2-8) 8th Cooling and Heating Mixed Operation In the seventh cooling / heating mixed operation, when the amount of water flowing into the first heat exchanger 11 is large, the control unit 3 slightly opens the fourth valve V4. As a result, a part of the water that has passed through the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4 and the second pipe P2 without flowing into the first heat exchanger 11.

[0104] (5-2-3) Features (5-2-3-1) In the air conditioning system 1b of this modified example, at least a portion of the water that has passed through the first heat exchanger 11 flows into the second heat exchanger 21, or at least a portion of the water that has passed through the second heat exchanger 21 flows into the first heat exchanger 11.

[0105] Here, water supplied from the heat source 2 exchanges heat with air or a heat transfer medium in the first heat exchanger 11 or the second heat exchanger 21, and then further exchanges heat with a heat transfer medium or air in the second heat exchanger 21 or the first heat exchanger 11. This allows for efficient heat recovery.

[0106] (5-2-3-2) The air conditioning system 1b of this modified example shown in FIG. 2 further includes a first pipe P1, a second pipe P2, a third pipe P3, a fourth pipe P4, a first valve V1, a second valve V2, a third valve V3, and a fourth valve V4. The first pipe P1 allows water to flow from the heat source 2 to the first heat exchanger 11. The second pipe P2 allows water to flow from the first heat exchanger 11 to the heat source 2. The third pipe P3 allows water to flow from the second pipe P2 to the second heat exchanger 21. The fourth pipe P4 allows water to flow from the second heat exchanger 21 to between the third pipe P3 and the heat source 2 in the second pipe P2. The first valve V1 is provided in the first pipe P1. The second valve V2 is provided in the second pipe P2 between the fourth pipe P4 and the third pipe P3. The third valve V3 is provided in the third pipe P3. The fourth valve V4 is provided in the fourth pipe P4.

[0107] Here, when the air to be sent into the room is heated in the third heat exchanger 22 while the air to be sent into the room is cooled in the first heat exchanger 11, and when the air to be sent into the room is cooled in the third heat exchanger 22 while the air to be sent into the room is heated in the first heat exchanger 11, the first valve V1 can be opened to allow water supplied from the heat source 2 to flow into the first heat exchanger 11 through the first pipe P1. Then, by closing the second valve V2 and opening the third valve V3, the water that has exchanged heat with the air in the first heat exchanger 11 can be allowed to flow into the second heat exchanger 21 through the second pipe P2 and the third pipe P3. Then, by opening the fourth valve V4, the water that has exchanged heat with the heat carrier medium in the second heat exchanger 21 can be returned to the heat source 2 through the fourth pipe P4 and the second pipe P2.

[0108] In addition, since the water flow is the same during the first and second mixed cooling and heating operations when the first heat exchanger 11 cools the air to be sent into the room, and during the fifth and sixth mixed cooling and heating operations when the first heat exchanger 11 heats the air to be sent into the room, the number of valves can be reduced.

[0109] (5-2-3-3) The air conditioning system 1b shown in FIG. 3 of this modified example further includes a first pipe P1, a second pipe P2, a fifth pipe P5, a sixth pipe P6, a first valve V1, a second valve V2, a fifth valve V5, and a sixth valve V6. The first pipe P1 allows water to flow from the heat source 2 to the first heat exchanger 11. The second pipe P2 allows water to flow from the first heat exchanger 11 to the heat source. The fifth pipe P5 allows water to flow from the first pipe P1 to the second heat exchanger 21. The sixth pipe P6 allows water to flow from the second heat exchanger 21 to the first pipe P1. The first valve V1 is provided in the first pipe P1 between the fifth pipe P5 and the sixth pipe P6. The second valve V2 is provided in the second pipe P2. The fifth valve V5 is provided in the fifth pipe P5. The sixth valve V6 is provided in the sixth pipe P6.

[0110] Here, when the air to be sent into the room is heated in the third heat exchanger 22 while the air to be sent into the room is cooled in the first heat exchanger 11, and when the air to be sent into the room is cooled in the third heat exchanger 22 while the air to be sent into the room is heated in the first heat exchanger 11, the first valve V1 is closed and the fifth valve V5 is opened, so that the water supplied from the heat source 2 can be made to flow into the second heat exchanger 21 through the first pipe P1 and the fifth pipe P5. Then, by opening the sixth valve V6, the water that has exchanged heat with the heat carrier medium in the second heat exchanger 21 can be made to flow into the first heat exchanger 11 through the sixth pipe P6 and the first pipe P1. Then, by opening the second valve V2, the water that has exchanged heat with the air in the first heat exchanger 11 can be returned to the heat source through the second pipe P2.

[0111] In addition, since the water flow is the same during the third and fourth mixed cooling / heating operations when the first heat exchanger 11 cools the air to be sent into the room, and during the seventh and eighth mixed cooling / heating operations when the first heat exchanger 11 heats the air to be sent into the room, the number of valves can be reduced.

[0112] (5-3) Variation 3 (5-3-1) Configuration In the above embodiment, the first heat exchanger 11 is a cold water coil, and in the first modification, the first heat exchanger 11 is a hot water coil, but the present invention is not limited thereto. In this modification, the first heat exchanger 11 has a cold water coil and a hot water coil, as shown in Figs. 4 to 7. In addition, in this modification, a mixed cooling and heating operation is possible in which the air to be sent into the room is heated in the third heat exchanger 22 when the air to be sent into the room is cooled in the first heat exchanger 11, and a mixed cooling and heating operation is possible in which the air to be sent into the room is cooled in the third heat exchanger 22 when the air to be sent into the room is heated in the first heat exchanger 11.

[0113] The air conditioning system 1c of this modification further includes the third pipe P3, the sixth pipe P6, the first valve V1, the second valve V2, the third valve V3, the fourth valve V4, the fifth valve V5, and the sixth valve V6, as in the modification 2. As in the modification 2, the heat transfer circuit 20 further includes a switching mechanism for switching between circulating the heat transfer medium through the compressor 23, the third heat exchanger 22, the expansion mechanism 24, and the second heat exchanger 21 in that order, and circulating the heat transfer medium through the compressor 23, the second heat exchanger 21, the expansion mechanism 24, and the third heat exchanger 22 in that order. As in the modification 2, the control unit 3 further controls the opening degrees of the first valve V1 to the sixth valve V6, the switching mechanism of the heat transfer circuit 20, and the like.

[0114] The air conditioning system 1c of this modified example is a four-pipe system in which four pipes (first pipes P1a, P1b, and second pipes P2a, P2b, which will be described later) are connected to the heat source 2.

[0115] Specifically, the heat source 2 of this modified example has a first heat source 2a that supplies water having cold heat (cold water) and a second heat source 2b that supplies water having hot heat (hot water).

[0116] The first heat exchanger 11 has a cold water coil 11a and a hot water coil 11b. The cold water coil 11a cools the air to be sent into the room with water supplied from the first heat source 2a. The hot water coil 11b heats the air to be sent into the room with water supplied from the second heat source 2b.

[0117] The first pipe P1 has a first pipe P1a that allows water to flow from the first heat source 2a to the cold water coil 11a, and a first pipe P1b that allows water to flow from the second heat source 2b to the hot water coil 11b.

[0118] The second piping P2 includes a second piping P2a for allowing water to flow from the cold water coil 11a to the first heat source 2a, and a second piping P2b for allowing water to flow from the hot water coil 11b to the second heat source 2b.

[0119] The third pipe P3 has a third pipe P3a that allows water to flow from the second pipe P2a to the second heat exchanger 21, and a third pipe P3b that allows water to flow from the second pipe P2b to the second heat exchanger 21.

[0120] The fourth piping P4 has a fourth piping P4a that flows water from the second heat exchanger 21 between the third piping P3a in the second piping P2a and the first heat source 2a, and a fourth piping P4b that flows water from the second heat exchanger 21 between the third piping P3b in the second piping P2b and the second heat source 2b.

[0121] The fifth pipe P5 has a fifth pipe P5a that allows water to flow from the first pipe P1a to the second heat exchanger 21, and a fifth pipe P5b that allows water to flow from the first pipe P1b to the second heat exchanger 21.

[0122] The sixth pipe P6 has a sixth pipe P6a that allows water to flow from the second heat exchanger 21 to the first pipe P1a, and a sixth pipe P6b that allows water to flow from the second heat exchanger 21 to the first pipe P1b.

[0123] The first valve V1 includes a first valve V1a provided in the first pipe P1a and a first valve V1b provided in the first pipe P1b. Here, the first valve V1a is provided in the first pipe P1a between the fifth pipe P5a and the sixth pipe P6a. The first valve V1b is provided in the first pipe P1b between the fifth pipe P5b and the sixth pipe P6b.

[0124] The second valve V2 includes a second valve V2a provided in the second pipe P2a between the fourth pipe P4a and the third pipe P3a, and a second valve V2b provided between the fourth pipe P4b and the third pipe P3b.

[0125] The third valve V3 includes a third valve V3a provided in the third pipe P3a and a third valve V3b provided in the third pipe P3b.

[0126] The fourth valve V4 has a fourth valve V4a provided in the fourth pipe P4a and a fourth valve V4b provided in the fourth pipe P4b.

[0127] The fifth valve V5 includes a fifth valve V5a provided in the fifth pipe P5a and a fifth valve V5b provided in the fifth pipe P5b.

[0128] The sixth valve V6 has a sixth valve V6a provided in the sixth pipe P6a and a sixth valve V6b provided in the sixth pipe P6b.

[0129] (5-3-2) Driving behavior Hereinafter, a description will be given of the mixed cooling and heating operation of the air conditioning system 1c of this modified example. Note that the air conditioning system 1c is also capable of full cooling operation and full heating operation.

[0130] (5-3-2-1) 1st Cooling and Heating Mixed Operation 4, the first mixed cooling and heating operation in which the cold water coil 11a is used as the first heat exchanger 11 will be described. In the first mixed cooling and heating operation, the hot water coil 11b is not used. In the first mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform a cooling operation in the room, and the second unit 40 supplies the supply air SA to perform a heating operation in the room.

[0131] The control unit 3 controls the first valve V1a, the third valve V3a, and the fourth valve V4a to be open, and the first valve V1b, the second valves V2a and V2b, the third valve V3b, the fourth valve V4b, the fifth valves V5a and V5b, and the sixth valves V6a and V6b to be closed.

[0132] The cold water from the first heat source 2a flows through the first pipe P1a to the cold water coil 11a of the first heat exchanger 11. The water that has exchanged heat with the air to be sent into the room in the cold water coil 11a flows through the second pipe P2a, the third pipe P3a, and the fifth pipe P5a to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 returns to the first heat source 2a through the fourth pipe P4a and the second pipe P2a.

[0133] In the first cooling / heating mixed operation, water that has been heated by heat exchange with air in the cold water coil 11a is caused to flow through the second heat exchanger 21, where the heat transfer medium is heated.

[0134] (5-3-2-2) Second cooling and heating mixed operation In the first cooling / heating mixed operation, when the amount of water flowing into the second heat exchanger 21 is insufficient, the control unit 3 slightly opens the fifth valve V5. As a result, in addition to the water that has passed through the chilled water coil 11a, the water from the first heat source 2a before flowing into the chilled water coil 11a flows into the second heat exchanger 21 through the fifth pipe P5.

[0135] (5-3-2-3) 3rd Heating and Cooling Mixed Operation 5, the third mixed cooling and heating operation in which the cold water coil 11a is used as the first heat exchanger 11 will be described. In the third mixed cooling and heating operation, the hot water coil 11b is not used. In the third mixed cooling and heating operation, the supply air SA supplied by the third unit 30 is used to perform indoor cooling operation, and the supply air SA supplied by the second unit 40 is used to perform indoor heating operation.

[0136] The control unit 3 controls the second valve V2a, the fifth valve V5a, and the sixth valve V6a to be opened, and the first valves V1a, V1b, the second valve V2b, the third valves V3a, V3b, the fourth valves V4a, V4b, the fifth valve V5b, and the sixth valve V6b to be closed.

[0137] The medium-temperature water from the first heat source 2a flows through the first pipe P1a and the fifth pipe P5a to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 flows through the fourth pipe P4a, the sixth pipe P6a, and the first pipe P1a to the cold water coil 11a. The water that has exchanged heat with the air in the cold water coil 11a returns to the first heat source 2a through the second pipe P2a.

[0138] In the third combined cooling and heating operation, the water cooled by heat exchange with the heat transfer medium in the second heat exchanger 21 is caused to flow through the chilled water coil 11a, and the air is cooled by the chilled water coil 11a.

[0139] (5-3-2-4) 4th Cooling and Heating Mixed Operation In the third cooling / heating mixed operation, when the amount of water flowing into the chilled water coil 11a is large, the control unit 3 slightly opens the fourth valve V4a. As a result, a part of the water that has passed through the second heat exchanger 21 returns to the heat source 2 through the fourth pipe P4a and the second pipe P2a without flowing into the chilled water coil 11a.

[0140] (5-3-2-5) 5th Cooling and Heating Mixed Operation 6, a fifth mixed cooling and heating operation in which the hot water coil 11b is used as the first heat exchanger 11 will be described. In the fifth mixed cooling and heating operation, the cold water coil 11a is not used. In the fifth mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform a heating operation of the room, and the second unit 40 supplies the supply air SA to perform a cooling operation of the room.

[0141] The control unit 3 controls the first valve V1b, the third valve V3b, and the fourth valve V4b to be opened, and the first valve V1a, the second valves V2a, V2b, the third valve V3a, the fourth valve V4a, the fifth valves V5a, V5b, and the sixth valves V6a, V6b to be closed.

[0142] Hot water from the second heat source 2b flows to the hot water coil 11b through the first pipe P1b. The water that has exchanged heat with the air to be sent into the room in the hot water coil 11b flows to the second heat exchanger 21 through the second pipe P2b, the third pipe P3b, and the fifth pipe P5b. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 returns to the second heat source 2b through the fourth pipe P4b and the second pipe P2b.

[0143] In the fifth cooling / heating mixed operation, the water cooled by heat exchange with the air in the hot water coil 11b is caused to flow through the second heat exchanger 21, where the heat transfer medium is cooled.

[0144] (5-3-2-6) 6th Cooling and Heating Mixed Operation In the fifth cooling / heating mixed operation, when the amount of water flowing into the second heat exchanger 21 is insufficient, the control unit 3 slightly opens the fifth valve V5b. As a result, in addition to the water that has passed through the hot water coil 11b, the water from the second heat source 2b before flowing into the hot water coil 11b flows into the second heat exchanger 21 through the fifth pipe P5b.

[0145] (5-3-2-7) 7th Cooling and Heating Mixed Operation 7, a seventh mixed cooling and heating operation in which the hot water coil 11b is used as the first heat exchanger 11 will be described. In the seventh mixed cooling and heating operation, the cold water coil 11a is not used. In the seventh mixed cooling and heating operation, the third unit 30 supplies the supply air SA to perform a heating operation of the room, and the second unit 40 supplies the supply air SA to perform a cooling operation of the room.

[0146] The control unit 3 controls the second valve V2b, the fifth valve V5b, and the sixth valve V6b to be opened, and the first valves V1a, V1b, the second valve V2a, the third valves V3a, V3b, the fourth valves V4a, V4b, the fifth valve V5a, and the sixth valve V6a to be closed.

[0147] The medium-temperature water from the second heat source 2b flows through the first pipe P1b and the fifth pipe P5b to the second heat exchanger 21. The water that has exchanged heat with the heat transfer medium in the second heat exchanger 21 flows through the fourth pipe P4b, the sixth pipe P6b, and the first pipe P1 to the hot water coil 11b. The water that has exchanged heat with the air in the hot water coil 11b returns to the second heat source 2b through the second pipe P2b.

[0148] In the seventh heating and cooling mixed operation, the water heated by heat exchange with the heat transfer medium in the second heat exchanger 21 is caused to flow through the hot water coil 11b, and the air is heated by the hot water coil 11b.

[0149] (5-3-2-8) 8th Cooling and Heating Mixed Operation In the seventh cooling / heating mixed operation, when the amount of water flowing into the hot water coil 11b is large, the control unit 3 slightly opens the fourth valve V4b. As a result, a part of the water that has passed through the second heat exchanger 21 returns to the second heat source 2b through the fourth pipe P4b and the second pipe P2b without flowing into the hot water coil 11b.

[0150] (5-3-3) Features Even if the air conditioning system 1c of this modified example is a four-pipe system, it has the same effects as the modified example 2 described above.

[0151] (5-4) Variation 4 (5-4-1) Configuration In the above embodiment, the third heat exchanger 22 passes air that has been heat exchanged with water in the first heat exchanger 11, but this is not limited to this. In this modification, the third heat exchanger 22 can pass air different from the air that has been heat exchanged with water in the first heat exchanger 11.

[0152] 8(A) and 8(B), the air conditioning system 1d further includes a fourth duct D4. The second unit 40 further includes a switching member .

[0153] The fourth duct D4 is connected to the third unit 30. The return air RA from the room passes through the fourth duct D4. Therefore, the return air RA flows from the fourth duct D4 to the second unit 40. Here, the return air RA flowing through the fourth duct D4 is air above the ceiling.

[0154] The switching member 42 switches between a mode in which the air that has been heat exchanged in the first heat exchanger 11 flows through the third heat exchanger 22 via the second duct D2, as shown in Figure 8(A), and a mode in which the return air RA from the room flows through the third heat exchanger 22 without passing through the second duct D2, as shown in Figure 8(B).

[0155] In the mode shown in Fig. 8(A), the switching member 42 communicates between the second duct D2 and the second unit 40, and blocks communication between the fourth duct D4, through which the return air RA passes, and the second unit 40. In the mode shown in Fig. 8(B), the switching member 42 communicates between the fourth duct D4 and the second unit 40, and blocks communication between the second duct D2 and the second unit 40. The switching member 42 has a structure that blocks communication between the second duct D2 and the fourth duct D4. Here, the switching member 42 is a slide-type damper.

[0156] The third heat exchanger 22 uses the switching member 42 to perform heat exchange between the air passing through the second duct D2 and a heat transfer medium, as shown in Figure 8(A), or to perform heat exchange between the return air RA from the room passing through the fourth duct D4 without passing through the second duct D2 and the heat transfer medium, as shown in Figure 8(B).

[0157] The second fan 41 circulates the supply air SA, which is the air that has passed through the second duct D2 and the third heat exchanger 22, into the room as shown in Fig. 8(A), or circulates the supply air SA, which is the air that has passed through the fourth duct D4 and the third heat exchanger 22, into the room as shown in Fig. 8(B). The second fan 41 adjusts the amount of air supplied into the room.

[0158] The control unit 3 of this modified example controls the operation of the switching member 42. Specifically, the control unit 3 moves the switching member 42 to the position shown in Fig. 8(A) so that the mode is such that the air that has been heat exchanged in the first heat exchanger 11 flows through the third heat exchanger 22 via the second duct D2. The control unit 3 also moves the switching member 42 to the position shown in Fig. 8(B) so that the mode is such that the return air RA from the room flows through the third heat exchanger 22 without passing through the second duct D2.

[0159] (5-4-2) Driving behavior 8(A) so that the control unit 3 sets the mode in which the air that has been heat exchanged in the first heat exchanger 11 flows through the third heat exchanger 22 via the second duct D2, the operation is the same as the mixed heating and cooling operation of the above embodiment. When the control unit 3 sets the mode in which the return air RA from the room flows through the third heat exchanger 22 via the fourth duct D4 so that the control unit 3 sets the mode in which the return air RA from the room flows through the third heat exchanger 22 via the fourth duct D4, the third heat exchanger 22 exchanges heat between the return air RA from the fourth duct D4 and the heat carrying medium.

[0160] (5-4-3) Features The air conditioning system 1d of this modified example further includes a second unit 40 having a third heat exchanger 22. The second unit 40 further includes a second fan 41 and a switching member 42. The second fan 41 flows air into the room. The switching member 42 switches between a mode in which the air that has been heat exchanged in the first heat exchanger 11 flows through the third heat exchanger 22 via the second duct D2, and a mode in which the return air RA from the room flows through the third heat exchanger 22 without passing through the second duct D2.

[0161] Here, the second fan 41 and the switching member 42 allow the air that has undergone heat exchange in the first heat exchanger 11 or the return air RA from the room to flow to the third heat exchanger 22. This allows the third heat exchanger 22 to exchange heat between the air that has undergone heat exchange in the first heat exchanger 11 or the return air and the heat medium. Therefore, the air that has undergone heat exchange in the first heat exchanger 11 or the return air can be selected according to the requirements in the room, thereby improving thermal efficiency.

[0162] (5-5) Variation 5 In the above embodiment, the first fan 12 of the first unit 10, the second fan 41 of the second unit 40, and the third fan 31 of the third unit 30 have been described as examples of fans that blow air from the first unit 10 into the room, but this is not limiting. The air conditioning system of the present disclosure includes a case where fan units are connected to the first duct D1 and the second duct D2, and a case where a variable air volume system (VAV) is connected. Specifically, the fans that blow air from the first unit 10 into the room may be only the first fan 12, or may be only the second fan 41 and the third fan 31.

[0163] In this modification, a variable air volume system (VAV) is provided in the first duct D1 and the second duct D2. The first unit 10 is provided with a first fan 12, similar to the above embodiment.

[0164] (5-6) Variation 6 In the above embodiment, the heat transport circuit 20 has the compressor 23, but is not limited to this. In this modification, water is circulated as the heat transport medium, and a pump is used instead of the compressor.

[0165] 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]

[0166] 1a, 1b, 1c, 1d: Air conditioning system 2,2a,2b :Heat source 3: Control section 10: First Unit 11: 1st heat exchanger 12: First Fan (Fan) 20: Heat transfer circuit 21:Second heat exchanger 22:Third heat exchanger 40: 2nd Unit 41: Second Fan (Fan) 42: Switching member D1: First duct D2: Second duct D3: Third duct D4: 4th duct P1, P1a, P1b: First piping P2, P2a, P2b: Second piping P3, P3a, P3b: Third piping P4, P4a, P4b: 4th pipe P5, P5a, P5b: 5th pipe P6, P6a, P6b: 6th pipe V1, V1a, V1b: First valve V2, V2a, V2b: Second valve V3, V3a, V3b: Third valve V4, V4a, V4b: 4th valve V5, V5a, V5b: 5th valve V6, V6a, V6b: 6th valve [Prior art documents] [Patent documents]

[0167] [Patent Document 1] Japanese Patent Application Publication No. 5-33970

Claims

1. a first unit (10) having a first heat exchanger (11) for exchanging heat between water supplied from a heat source (2) and air to be sent into a room; a first duct (D1) and a second duct (D2) through which air that has been heat exchanged in the first heat exchanger passes; a fan (12) for blowing air from the first unit into the room; a heat transfer circuit (20) including a second heat exchanger (21) for performing heat exchange between the water supplied from the heat source and a heat transfer medium, and a third heat exchanger (22) for performing heat exchange between the air passing through the second duct and the heat transfer medium, in which the heat transfer medium circulates; Equipped with An air conditioning system (1a), wherein the air to be sent into the room is heated in the third heat exchanger when the air to be sent into the room is cooled in the first heat exchanger, or the air to be sent into the room is cooled in the third heat exchanger when the air to be sent into the room is heated in the first heat exchanger.

2. At least a portion of the water that has passed through the first heat exchanger flows into the second heat exchanger, or at least a portion of the water that has passed through the second heat exchanger flows into the first heat exchanger. An air conditioning system (1b) according to claim 1.

3. A first pipe (P1) for flowing the water from the heat source to the first heat exchanger; A second pipe (P2) for flowing the water from the first heat exchanger to the heat source; A third pipe (P3) for flowing the water from the second pipe to the second heat exchanger; A fourth pipe (P4) for flowing the water from the second heat exchanger to between the third pipe and the heat source in the second pipe; A first valve (V1) provided in the first pipe; a second valve (V2) provided in the second pipe between the fourth pipe and the third pipe; A third valve (V3) provided in the third pipe; A fourth valve (V4) provided in the fourth pipe; Further comprising:

3. An air conditioning system according to claim 1 or 2.

4. A first pipe (P1) for flowing the water from the heat source to the first heat exchanger; A second pipe (P2) for flowing the water from the first heat exchanger to the heat source; A fifth pipe (P5) for flowing the water from the first pipe to the second heat exchanger; A sixth pipe (P6) for flowing the water from the second heat exchanger to the first pipe; A first valve (V1) provided in the first pipe between the fifth pipe and the sixth pipe; A second valve (V2) provided in the second pipe; A fifth valve (V5) provided in the fifth pipe; A sixth valve (V6) provided in the sixth pipe; Further comprising:

3. An air conditioning system according to claim 1 or 2.

5. Further comprising a third duct (D3) connected to the first unit, the first duct, and the second duct, The third duct supplies air that has been heat exchanged in the first heat exchanger to the first duct and the second duct.

3. An air conditioning system according to claim 1 or 2.

6. The heat transfer medium is a refrigerant.

3. An air conditioning system according to claim 1 or 2.

7. A control unit (3) for controlling the operation of the heat transport circuit, the control unit executes a first mode in which the heat transport circuit is used and a second mode in which the heat transport circuit is not used.

3. An air conditioning system according to claim 1 or 2.

8. A second unit (40) having the third heat exchanger, The second unit is A fan (41) for blowing the air inside the room; a switching member (42) that switches between a mode in which the air that has been heat exchanged in the first heat exchanger flows through the third heat exchanger via the second duct and a mode in which the return air from the room flows through the third heat exchanger without passing through the second duct; Further comprising 3. An air conditioning system according to claim 1 or 2.

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