Building air conditioning system

Abstract

To provide an air conditioning system for a building that can restrain condensation from forming on an air conveying member such as an air conditioning duct.SOLUTION: An air conditioning system 30 is applied to a building 10 comprising a plurality of rooms 14-17, and an underfloor space 22. The air conditioning system 30 comprises: an indoor unit 32 capable of performing at least cooling operation, and for generating conditioned air for cooling during the cooling operation; and a connection duct 51, a branch chamber 52, and air conditioning ducts 53-55 arranged in the underfloor space 22, and for conveying the conditioned air generated by the indoor unit 32, to the respective living rooms 14-16. The conditioned air conveyed to the respective living rooms 14-16 is returned to the indoor unit 32. The indoor unit 32 takes the returned air as return air RA, and generates the conditioned air by exchanging heat between the return air RA and a refrigerant. The indoor unit 32 is provided with a return air guide member 61 for guiding a portion of the return air RA taken into the indoor unit 32, to the underfloor space 22 without exchanging the heat.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a building air conditioning system.

Background Art

[0002] In buildings such as houses, there may be provided a whole-building air conditioner that collectively conditions a plurality of living spaces (for example, Patent Document 1). The whole-building air conditioner includes an indoor unit provided indoors and an outdoor unit provided outdoors. The indoor unit generates conditioned air (cooling and heating air), and supplies the generated conditioned air to each living space to be conditioned via an air conditioning duct. Thereby, each living space is air-conditioned (heated and cooled) by the supplied conditioned air.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a building, an air conditioning duct is disposed, for example, in a space under the floor. Since the space under the floor is a closed space, heat and moisture tend to accumulate in summer. Therefore, when the cooling operation of the air conditioner is performed, it is considered that the surface of the air conditioning duct becomes low temperature due to the cooling air flowing inside. In that case, there is a concern that condensation may occur on the surface of the air conditioning duct in the space under the floor.

[0005] The present invention has been made in view of the above circumstances, and a main object thereof is to provide a building air conditioning system capable of suppressing condensation from occurring on an air conveyance member such as an air conditioning duct.

Means for Solving the Problems

[0006] To solve the above problems, the air conditioning system for a building according to the first invention is applied to a building having a plurality of living spaces and a back space which is a space under the floor or in the attic of the living space, and is capable of at least cooling operation. During the cooling operation, an air conditioner generates air for air conditioning for cooling, and an air conveyance member disposed in the back space conveys the air for air conditioning generated by the air conditioner to each living space. The air for air conditioning conveyed to each living space is configured to flow back to the air conditioner. The air conditioner takes in the returned air as return air and generates air for air conditioning by exchanging heat between the return air and a refrigerant. The air conditioning system for a building is characterized by comprising return air guiding means for guiding a part of the return air taken into the air conditioner to the back space without performing the heat exchange.

[0007] In the air conditioning system of the present invention, the air for air conditioning for cooling generated by the cooling operation of the air conditioner is conveyed to each living space by the air conveyance member. The conveyed air for air conditioning then flows back to the air conditioner. And the air conditioner takes in the returned air as return air and generates air for air conditioning. Here, it is considered that the air used for air conditioning (cooling) of the living space and then flowing back to the air conditioner, that is, the return air, is relatively high-temperature and dry air. Therefore, in the first invention, paying attention to such a point, a part of the return air taken into the air conditioner is guided to the back space by the return air guiding means without performing heat exchange. Thereby, relatively high-temperature and dry air can be sent to the back space, so that condensation on the air conveyance member disposed in the back space can be suppressed.

[0008] The air conditioning system for a building according to the second invention is, in the first invention, characterized in that the air conditioner has an air passage for sending the return air taken into the air conditioner to a heat exchange section that performs the heat exchange, and a blowing means for generating a flow of air toward the heat exchange section in the air passage, and the return air guiding means guides a part of the return air from a position downstream of the blowing means and upstream of the heat exchange section in the air passage to the back space.

[0009] According to the second invention, by utilizing the air flow by the air blowing means generally provided in the air conditioner, a part of the return air can be guided to the back space. As a result, since dry air can be actively guided to the back space, it is possible to further suppress the occurrence of condensation on the air conveyance member.

[0010] The air conditioning system of the building of the third invention is, in the first or second invention, as the air conveyance member, having a branch chamber connected to the air conditioner and a plurality of air conditioning ducts connected to the branch chamber, and the conditioned air generated by the air conditioner is conveyed to each living space through the branch chamber and each air conditioning duct, and the return air guiding means is a tubular return air guiding member that extends from the air conditioner to the back space and guides a part of the return air to the back space through the inside, and the return air guiding member is characterized in that it guides a part of the return air around the branch chamber.

[0011] In the branch chamber to which a plurality of air conditioning ducts are connected, since the conditioned air flowing through each air conditioning duct flows respectively, the outer surface is likely to become low in temperature and condensation is likely to occur. Therefore, in the third invention, the return air is guided around the branch chamber through the return air guiding member. Thereby, it is possible to preferably suppress the occurrence of condensation in the branch chamber.

[0012] The air conditioning system of the building of the fourth invention is, in the third invention, in the back space, a duct parallel arrangement portion is provided in which a plurality of the air conditioning ducts extend in the same direction at positions close to each other, and the return air guiding member is characterized in that it guides a part of the return air to the duct parallel arrangement portion.

[0013] In a portion where a plurality of air conditioning ducts are close to each other and extend in the same direction, the surrounding air is likely to be cooled, and therefore condensation is likely to occur. Therefore, in the fourth invention, the return air is guided around the duct parallel arrangement portion through the return air guiding member. Thereby, it is possible to preferably suppress the occurrence of condensation in the duct parallel arrangement portion.

[0014] The air conditioning system for a building according to the fifth invention is characterized in that, in any one of the first to fourth inventions, the air conditioning apparatus has adjustment means for adjusting the amount of return air guided from the air conditioning apparatus to the back space by the return air guiding means.

[0015] If the amount of return air led to the back space is large, there may be insufficient return air for generating conditioned air, and there is a risk that the living space cannot be sufficiently air-conditioned. On the other hand, if the amount of return air led to the back space is small, there is a risk that condensation cannot be suppressed in the back space. Therefore, in the fifth invention, in view of these points, the amount of return air led to the back space can be adjusted. Thereby, it becomes possible to adjust the amount of return air led to the back space to an appropriate amount according to the temperature situation of the living space and the condensation situation in the back space.

[0016] The air conditioning system for a building according to the sixth invention is characterized in that, in the fifth invention, it includes temperature detection means for detecting the temperature of the living space and control means for controlling the adjustment means, and the control means controls the adjustment means based on the temperature of the living space detected by the temperature detection means.

[0017] According to the sixth invention, the amount of return air led to the back space is adjusted based on the temperature of the living space. Therefore, for example, when the temperature of the living space becomes high in summer, the generation of conditioned air can be promoted by reducing the amount of return air led to the back space. Thereby, the living space can be quickly cooled.

[0018] The air conditioning system for a building according to the seventh invention is characterized in that, in the sixth invention, it includes condensation detection means for detecting that condensation has occurred in the back space, and when the condensation detection means detects the occurrence of condensation, the control means controls the adjustment means so that the amount of return air led to the back space increases.

[0019] According to the seventh invention, when condensation occurs in the back space, the amount of return air led to the back space increases, so the occurrence of condensation can be preferably suppressed.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0021] Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings.

[0022] (First Embodiment) As shown in FIG. 1, a building 10 such as a house is provided above the foundation 11. The foundation 11 is composed of a mat foundation made of reinforced concrete and is provided over the entire outer peripheral portion of the building 10.

[0023] The building 10 is a two-story building, and a plurality of rooms 14 to 17 are provided in the first floor portion 12 thereof. Among these rooms 14 to 17, the rooms 14 to 16 are composed of, for example, a living room, a dining room, a Japanese-style room, a bedroom, etc., and hereinafter may be referred to as living rooms 14 to 16. Further, the room 17 is a machine room in which the indoor unit 32 of the air conditioning system 30 described later is installed, and hereinafter may be referred to as the machine room 17. The rooms 14 to 17 are partitioned from each other by partition walls 18. Through ventilation openings 19 provided in the partition walls 18 and door undercuts, etc., adjacent rooms 14 to 17 can be constantly ventilated with each other.

[0024] A floor portion 21 is provided in the first floor portion 12, and the floor surfaces of the rooms 14 to 17 are formed by this floor portion 21. Note that the floor portion 21 is configured to have a floor surface material and floor beams that support the floor surface material.

[0025] Below the bed section 21, a space 22 under the floor is provided. The space 22 under the floor is vertically partitioned from the rooms 14 to 17 by the bed section 21. Also, the space 22 under the floor is surrounded by the foundation 11 on its periphery. Note that the space 22 under the floor corresponds to the back space.

[0026] The building 10 is provided with a full-building air conditioning system 30. Below, the configuration of the air conditioning system 30 will be described.

[0027] The air conditioning system 30 performs air conditioning on each of the living rooms 14 to 16 on the first floor portion 12 of the building 10 as the air conditioning target. The air conditioning system 30 is a heat pump type air conditioning system and includes an indoor unit 32 provided indoors and an outdoor unit 33 provided outdoors. The indoor unit 32 and the outdoor unit 33 are connected via a refrigerant pipe 34. In FIG. 1, for the sake of convenience, the refrigerant pipe 34 is shown by a dotted line. Note that the indoor unit 32 corresponds to the air conditioning device. Also, each of the living rooms 14 to 16 corresponds to the "living space".

[0028] The indoor unit 32 is installed in the machine room 17 as described above and is vertically placed on the floor surface of the machine room 17. The indoor unit 32 is capable of performing at least cooling operation and heating operation. The indoor unit 32 takes in the air in the machine room 17 as return air RA and generates conditioned air (cooling air and heating air) by adjusting the temperature of the air. That is, during the cooling operation, the indoor unit 32 generates cooling air by cooling the air taken in from the machine room 17, and during the heating operation, the indoor unit 32 generates heating air by heating the air taken in from the machine room 17.

[0029] As shown in FIG. 2, the indoor unit 32 has an air passage 35 through which air flows inside. On the side plate portion of the indoor unit 32, at its upper part, a return air intake 38 for taking in the return air RA in the machine room 17 into the air passage 35 is formed. A filter 38a is attached to the return air intake 38. Thereby, it is possible to prevent foreign matters such as dust from entering the inside of the indoor unit 32.

[0030] The indoor unit 32 is provided with a heat exchanger 41 and a fan 42. The heat exchanger 41 is provided in the middle of the air passage 35 that extends from the return air intake 38 in the indoor unit 32. The heat exchanger 41 is connected to the refrigerant pipe 34 and causes heat exchange between the refrigerant flowing through the refrigerant pipe 34 and the return air RA flowing through the air passage 35. The return air RA in the air passage 35 is cooled or heated by the heat exchange of the heat exchanger 41 and thereby becomes cooling air or heating air (air for air conditioning).

[0031] The fan 42 is provided in the air passage 35 of the indoor unit 32 on the downstream side of the return air intake 38 and on the upstream side of the heat exchanger 41. The fan 42 causes an air flow from the return air intake 38 toward the heat exchanger 41 (and thus the downstream side) in the air passage 35. Note that the heat exchanger 41 corresponds to the heat exchange section and the fan 42 corresponds to the air blowing means.

[0032] A duct connection port 45 to which the connection duct 51 is connected is formed on the bottom surface portion of the indoor unit 32. The duct connection port 45 is formed on the downstream side of the heat exchanger 41 in the air passage 35 and is located at the downstream end of the air passage 35. The air for air conditioning generated by the heat exchange of the heat exchanger 41 is sent to the duct connection port 45.

[0033] The connection duct 51 is connected to the duct connection port 45 of the indoor unit 32. The connection duct 51 penetrates the floor portion 21 of the machine room 17 and extends to the underfloor space 22 (see FIG. 1). A branch chamber 52 is provided in the underfloor space 22 (specifically, directly below the indoor unit 32). The branch chamber 52 is connected to the indoor unit 32 via the connection duct 51.

[0034] In the branch chamber 52, in addition to the connection duct 51, a plurality of air-conditioning ducts 53 to 55 are also connected. These air-conditioning ducts 53 to 55 are provided in the under-floor space 22, similar to the branch chamber 52. Specifically, the air-conditioning duct 53 extends toward the living room 14, the air-conditioning duct 54 extends toward the living room 15, and the air-conditioning duct 55 extends toward the living room 16. Among the air-conditioning ducts 53 to 55, the two air-conditioning ducts 54 and 55 extending toward the living rooms 15 and 16 extend in the same direction from the branch chamber 52. In FIG. 1, for the sake of convenience, it is shown as if the air-conditioning duct 54 exists above the air-conditioning duct 55, but actually, the air-conditioning ducts 53 to 55 are all laid on the bottom surface of the under-floor space 22. Also, the connection duct 51, the branch chamber 52, and each of the air-conditioning ducts 53 to 55 all correspond to air conveyance members.

[0035] To each of the air-conditioning ducts 53 to 55, an air supply outlet 58 provided in the floor portion 21 of each of the living rooms 14 to 16 is connected. The air-conditioning air generated by the indoor unit 32 is supplied to the air supply outlets 58 of each of the living rooms 14 to 16 via the connection duct 51, the branch chamber 52, and the air-conditioning ducts 53 to 55, and the supplied air-conditioning air is blown out as the air supply SA into each of the living rooms 14 to 16 from each of the air supply outlets 58. Thereby, air-conditioning (heating and cooling) of each of the living rooms 14 to 16 is performed.

[0036] Also, in the building 10, as described above, the living rooms 14 to 16 and the machine room 17 can be constantly ventilated through the ventilation openings 19 provided in the partition wall 18, the door undercuts, and the like. The air-conditioning air (air supply SA) supplied to each of the living rooms 14 to 16 flows from each of the living rooms 14 to 16 as the return air RA through the ventilation openings 19 and the like into the machine room 17 and returns (flows back) to the indoor unit 32. The indoor unit 32 regenerates the air-conditioning air based on the returned return air RA. In this way, the present air-conditioning system 30 is an air-circulation type air-conditioning system.

[0037] In each of the air-conditioning ducts 54 and 55, a predetermined length portion (hereinafter referred to as predetermined length portions 54a and 55a) extending from the branch chamber 52 extends in the same direction at positions close to each other. In this case, a duct juxtaposition portion 57 is formed by these predetermined length portions 54a and 55a. Specifically, each of the predetermined length portions 54a and 55a constituting the duct juxtaposition portion 57 extends in a substantially straight line and parallel to each other.

[0038] Incidentally, the outer surface temperature of the air conveyance member is affected by the temperature of the air-conditioning air flowing inside the air conveyance member. And the air around the air conveyance member may be cooled or heated by the air conveyance member. For this reason, for example, when the air-conditioning system 30 is performing a cooling operation, the air around the air conveyance member may be cooled through the air conveyance member by the cooling air flowing through the air conveyance member. When the air-conditioning system 30 is performing a heating operation, the air around the air conveyance member may be heated through the air conveyance member by the heating air flowing through the air conveyance member. And such a phenomenon is considered to occur remarkably around the connection duct 51 and the branch chamber 52 through which a large amount of air-conditioning air flows, and around the duct juxtaposition portion 57 where a plurality of ducts are juxtaposed.

[0039] For this reason, for example, in summer, when the air in the underfloor space 22 is in a high temperature and high humidity state, when the cooling operation of the indoor unit 32 (and thus the air-conditioning system 30) is performed, there is a concern about the occurrence of dew condensation around the connection duct 51, the branch chamber 52, and the duct juxtaposition portion 57 in the underfloor space 22.

[0040] Therefore, in view of the above points, the air-conditioning system 30 of the present embodiment includes a return air guiding member 61 that guides a part of the return air RA taken into the indoor unit 32 to the underfloor space 22 during the cooling operation. Hereinafter, the configuration regarding this return air guiding member 61 will be described.

[0041] The return air guiding member 61 is composed of, for example, a hollow square duct. One end portion of the return air guiding member 61 serves as a connection portion 62 connected to the indoor unit 32, and the other end portion (open end portion) serves as a return air outlet 63 that blows out the return air RA.

[0042] On the side surface of the indoor unit 32, a connection port 65 to which the connection portion 62 of the return air guiding member 61 is connected is formed (see Fig. 2). The connection port 65 communicates with the air passage 35 of the indoor unit 32. Specifically, it communicates with the air passage 35 on the downstream side of the fan 42 and on the upstream side of the heat exchanger 41. Thereby, a part of the return air RA taken into the air passage 35 is guided from the downstream side of the fan 42 and the upstream side of the heat exchanger 41 in the air passage 35 into the interior of the return air guiding member 61 through the connection port 65. Therefore, in this case, a part of the return air RA taken into the air passage 35 can be guided to the underfloor space 22 without being guided to the heat exchanger 41, that is, without performing heat exchange by the heat exchanger 41.

[0043] The connection portion 62 of the return air guiding member 61 is connected to the connection port 65. The return air guiding member 61 extends downward from the connection portion 62 and penetrates the floor portion 21 of the machine room 17. A bending portion 64 is provided in the portion of the return air guiding member 61 located in the underfloor space 22. Due to this bending portion 64, the return air outlet 63 faces the connection duct 51, the branch chamber 52, and the duct parallel arrangement portion 57 (see Fig. 1).

[0044] When a part of the return air RA is guided from the air passage 35 of the indoor unit 32 to the return air guiding member 61, the return air RA flows through the interior of the return air guiding member 61 toward the underfloor space 22 side and is discharged from the return air outlet 63 toward the connection duct 51, the branch chamber 52, and the duct parallel arrangement portion 57. Thereby, the return air guiding member 61 guides the return air RA around the connection duct 51, the branch chamber 52, and the duct parallel arrangement portion 57.

[0045] When the air conditioner system 30 is operating in cooling mode during summer, the return air RA is hotter and drier compared to the air surrounding the connection duct 51, the branch chamber 52, and the duct parallel arrangement section 57. Therefore, when the return air RA is introduced, the air surrounding the connection duct 51, the branch chamber 52, and the duct parallel arrangement section 57 becomes warmer and drier. This can suppress the occurrence of condensation in the connection duct 51, the duct parallel arrangement section 57, and the branch chamber 52.

[0046] Incidentally, the air conditioner system 30 performs air conditioning management for each of the rooms 14 - 16 by circulating and temperature - adjusting the internal air of each room 14 - 17. Therefore, if too much return air RA is released into the under - floor space 22, there is a concern that the air volume of the supply air SA will be insufficient, causing problems in the air conditioning management of each of the rooms 14 - 16.

[0047] Therefore, the air conditioner system 30 of this embodiment has, as operation modes, a "return - air guiding mode" in which the return air RA is guided to the under - floor space 22 by the return - air guiding member 61, and a "return - air guiding stop mode" in which the return - air guiding member 61 does not guide the return air RA to the under - floor space 22. Further, in the return - air guiding mode, there are a "first return - air guiding mode" in which the return air RA is guided to the under - floor space 22 to the maximum extent, and a "second return - air guiding mode" in which the amount of the return air RA guided to the under - floor space 22 is restricted more than in the first return - air guiding mode. The air conditioner system 30 automatically switches among the first return - air guiding mode, the second return - air guiding mode, and the return - air guiding prohibition mode according to the situation in the building 10.

[0048] The indoor unit 32 has a shutter 66 that can open and close the connection port 65. The shutter 66 has a rectangular plate shape and is provided in the air passage 35. Specifically, the shutter 66 is connected to the side plate portion of the indoor unit 32 via a rotation shaft 67 at its lower end portion, and the shutter 66 is opened and closed by rotating around the rotation shaft 67. The rotation shaft 67 is connected to a drive unit 68 composed of an electric motor. The shutter 66 is opened and closed by the drive unit 68.

[0049] In addition, the shutter 66 has a variable opening degree in steps. Specifically, by its rotation, the shutter 66 can be switched to a "fully open position" where the shutter 66 is in a fully open state, a "half open position" where the shutter 66 is in a half open state, and a "closed position" where the shutter 66 is in a fully closed state.

[0050] When the shutter 66 is in the fully open position or the half open position, its upper surface is provided so as to block a part of the flow of the return air RA. Thereby, a part of the return air RA flowing through the air passage 35 of the indoor unit 32 can be guided to the return air guiding member 61 along the shutter 66. Also, the angle formed by the plate surface (upper surface) of the shutter 66 and the plate surface of the side plate portion of the indoor unit 32 is about 90° when the shutter 66 is in the fully open position, and about 45° when the shutter 66 is in the half open position. For this reason, in the case of the fully open position, the flow of the return air RA toward the heat exchanger 41 is blocked more greatly than in the case of the half open position. Therefore, when the shutter 66 is in the fully open position, more return air RA can be guided to the return air guiding member 61 than when it is in the half open position. On the other hand, when the shutter 66 is in the closed position, since the connection port 65 is closed, all of the return air RA flows to the heat exchanger 41.

[0051] The shutter 66 is positioned in the fully open position when the air conditioning system 30 is in the first return air guiding mode, in the half open position when in the second return air guiding mode, and in the closed position when in the return air guiding stop mode. Thereby, by switching the operation mode of the air conditioning system 30, it is possible to adjust the amount of the return air RA guided to the underfloor space 22. Note that the shutter 66 corresponds to an adjustment means.

[0052] In each of the rooms 14 to 16, a room temperature sensor 75 (corresponding to a temperature detection means) for detecting the room temperature of each of the rooms 14 to 16 is provided. Thereby, the room temperature in each of the rooms 14 to 16 is sequentially detected.

[0053] In the space 22 under the bed, a dew condensation detection sensor 76 (corresponding to dew condensation detection means) for detecting the occurrence of dew condensation water is provided. Specifically, the dew condensation detection sensor 76 is provided in the duct juxtaposition part 57 where dew condensation water is likely to occur. Thereby, the occurrence state of dew condensation water in the duct juxtaposition part 57 is sequentially detected.

[0054] The air conditioning system 30 includes a controller 70 as control means. The controller 70 is a well-known microcomputer having a CPU and various memories, and has a storage unit 70a in which various information is stored. The controller 70 is built in a remote controller 71 provided on the wall surface of the living room 15. Further, the remote controller 71 has an operation unit 72 operated by the occupant.

[0055] A room temperature sensor 75 and a dew condensation detection sensor 76 are connected to the controller 70. The detection result by the room temperature sensor 75 and the detection result by the dew condensation detection sensor 76 are sequentially input to the controller 70. The controller 70 sequentially stores the above detection results in the storage unit 70a.

[0056] A drive unit 68 is connected to the controller 70. The controller 70 executes drive control of the drive unit 68 (that is, opening / closing control of the shutter 66) based on the detection result by the room temperature sensor 75.

[0057] An operation unit 72 is connected to the controller 70. The controller 70 controls the indoor unit 32 based on the operation of the operation unit 72 by the occupant.

[0058] Subsequently, the operation mode switching process executed by the controller 70 will be described with reference to FIG. 3. Note that this process is repeatedly executed at a predetermined cycle during the operation of the indoor unit 32 (and thus the air conditioning system 30).

[0059] In step S11, it is determined whether the indoor unit 32 is in the cooling operation. If it is in the cooling operation, a YES determination is made and the process proceeds to step S12. If it is not in the cooling operation, a NO determination is made and this process ends.

[0060] In step S12, it is determined whether the operation mode of the air conditioning system 30 is the first return air guiding mode. If it is the first return air guiding mode, a YES determination is made and the process proceeds to step S13. If it is the second return air guiding mode or the return air guiding stop mode, a NO determination is made and the process proceeds to step S21.

[0061] In step S13, it is determined whether all of the room temperatures of each of the rooms 14 to 16 acquired by the room temperature sensor 75 are equal to or lower than a predetermined temperature T1. The predetermined temperature T1 is the air conditioning set temperature set by the occupant and is set to, for example, 27°C. In the case of a YES determination, this process ends. In the case of a NO determination, that is, when at least any one of the room temperatures of the rooms 14 to 16 is higher than the predetermined temperature T1, the process proceeds to step S14. Note that the predetermined temperature T1 is stored in the storage unit 70a in advance.

[0062] In step S14, the operation mode of the air conditioning system 30 is switched from the first return air guiding mode to the second return air guiding mode. In other words, the shutter 66 is displaced from the fully open position to the half-open position to limit the amount of the return air RA guided to the underfloor space 22. Then, this process ends.

[0063] In step S21, it is determined whether the operation mode of the air conditioning system 30 is the second return air guiding mode. If it is the second return air guiding mode, a YES determination is made and the process proceeds to step S21. If it is the return air guiding stop mode, a NO determination is made and the process proceeds to step S31.

[0064] In step S22, it is determined whether all of the room temperatures of each of the rooms 14 to 16 acquired by the room temperature sensor 75 are equal to or lower than a predetermined temperature T1. In the case of a YES determination, the process proceeds to step S23. In the case of a NO determination, the process proceeds to step S25.

[0065] In step S23, the operation mode of the air conditioning system 30 is switched from the second return air guiding mode to the first return air guiding mode. In other words, the shutter 66 is displaced from the half-open position to the fully open position so that more return air RA flows through the underfloor space 22. Then, this process ends.

[0066] In step S25, it is determined whether all of the room temperatures of each of the rooms 14 to 16 acquired by the room temperature sensor 75 are equal to or lower than a predetermined temperature T2. The predetermined temperature T2 is set higher than the predetermined temperature T1 and is stored in the storage unit 70a in advance. Also, the predetermined temperature T2 is set to a temperature at which the occupants in the rooms 14 to 16 do not feel uncomfortably hot. For example, when the predetermined temperature T1 is 27°C, the predetermined temperature T2 is set to 29°C. If all of the room temperatures of each of the rooms 14 to 16 are equal to or lower than the predetermined temperature T2, a YES determination is made and this process ends. If at least any one of the room temperatures of each of the rooms 14 to 16 exceeds the predetermined temperature T2, a NO determination is made and the process proceeds to step S26. Note that the predetermined temperature T2 may be set by the occupants themselves, or may be automatically determined according to the set value of the predetermined temperature T1, such as "the predetermined temperature T2 is the temperature obtained by adding 2°C to the predetermined temperature T1".

[0067] In step S26, the operation mode of the air conditioning system 30 is switched from the second return air guiding mode to the return air guiding stop mode. In other words, the shutter 66 is displaced from the half-open position to the closed position so that the return air RA is not guided to the underfloor space 22. Then, this process ends.

[0068] In step S31, it is determined whether all of the room temperatures of each of the rooms 14 to 16 acquired by the room temperature sensor 75 are equal to or lower than the predetermined temperature T2. If the determination is YES, the process proceeds to step S32. If the determination is NO, the process proceeds to step S33.

[0069] In step S32, the operation mode of the air conditioning system 30 is switched from the return air guiding stop mode to the second return air guiding mode. In other words, the shutter 66 is displaced from the closed position to the semi-open position to start guiding the return air RA to the underfloor space 22. However, since it is also necessary to cool the living rooms 14 to 16, the amount of the return air RA guided to the underfloor space 22 is limited. Then, this process ends.

[0070] In step S33, it is determined whether the dew condensation detection sensor 76 has detected the generation of dew condensation water. If the determination is YES, the process proceeds to step S34. If the determination is NO, this process ends.

[0071] In step S34, similar to step S32, the operation mode of the air conditioning system 30 is switched from the return air guiding stop mode to the second return air guiding mode. Then, this process ends.

[0072] As described above, in the operation mode switching process, based on the comparison between the room temperatures of the living rooms 14 to 16 and the predetermined temperatures T1 and T2, the amount of the return air RA guided from the indoor unit 32 to the underfloor space 22 is adjusted. When the room temperatures of the living rooms 14 to 16 are equal to or lower than the predetermined temperature T1, it means that the room temperatures of the living rooms 14 to 16 have already reached the air conditioning set temperature. In this case, the air conditioning system 30 can maintain the room temperatures of the living rooms 14 to 16 only by supplying a small amount of the supply air SA to the living rooms 14 to 16. Therefore, the air conditioning system 30 takes the first return air guiding mode and is configured to maximize the amount of the return air RA guided to the underfloor space 22.

[0073] In addition, when at least one of the room temperatures of the living rooms 14 to 16 is greater than a predetermined temperature T1 and all of the room temperatures of the living rooms 14 to 16 are equal to or less than a predetermined temperature T2, although the room temperatures of the living rooms 14 to 16 have not reached the air-conditioning set temperature, it can be considered that the temperatures in the living rooms 14 to 16 have reached a level where the occupants in the living rooms 14 to 16 do not feel uncomfortable. In this case, although the living rooms 14 to 16 should be further cooled, even if the cooling rate of the living rooms 14 to 16 slightly decreases, it is considered that the occupants can spend time in the living rooms 14 to 16 without experiencing such discomfort. Therefore, the air-conditioning system 30 enters the second return air guiding mode and guides the return air RA to the underfloor space 22 while restricting the guiding amount.

[0074] On the other hand, when at least one of the room temperatures of the living rooms 14 to 16 exceeds the predetermined temperature T2, the occupants in the living rooms 14 to 16 may feel uncomfortable and are considered to hope that the living rooms 14 to 16 are cooled more quickly. In this case, the air-conditioning system 30 enters the return air guiding stop mode, stops guiding the return air RA to the underfloor space 22, and maximizes the supply air SA amount to the living rooms 14 to 16.

[0075] However, when the dew condensation detection sensor 76 detects the generation of dew condensation water, even if at least one of the room temperatures of the living rooms 14 to 16 exceeds the predetermined temperature T2, the return air RA is guided to the underfloor space 22. In this case, since both the cooling of the living rooms 14 to 16 and the suppression of dew condensation in the underfloor space 22 are highly necessary, the air-conditioning system 30 is configured to enter the second return air guiding mode.

[0076] Although not shown in FIG. 3, when the power supply of the air-conditioning system 30 is turned off, the shutter 66 assumes the closed position. Also, the operation mode of the air-conditioning system 30 can be switched by the occupant operating the operation unit 72 of the remote controller 71.

[0077] According to the configuration of the first embodiment described in detail above, the following excellent effects can be obtained.

[0078] · In the above-described first embodiment, the air-conditioned air for cooling generated by the cooling operation of the indoor unit 32 is conveyed to the living rooms 14 to 16 through the connection duct 51, the branch chamber 52, and the respective air-conditioning ducts 53 to 55. The conveyed air-conditioned air then returns to the indoor unit 32. Then, the indoor unit 32 takes in the returned air as return air RA and generates air-conditioned air. Here, it is considered that the air used for cooling the living rooms 14 to 16 and then returning to the indoor unit 32, that is, the return air RA, is relatively warm and dry air. Here, in the above-described first embodiment, a part of the return air RA taken into the indoor unit 32 is guided to the underfloor space 22 by the return air guiding member 61 without heat exchange. Thereby, since relatively high-temperature and dry air can be sent to the underfloor space 22, it is possible to suppress the occurrence of dew condensation in the connection duct 51, the branch chamber 52, and the air-conditioning ducts 53 to 55 disposed in the underfloor space 22.

[0079] · In the above-described first embodiment, by utilizing the air flow by the fan 42, a part of the return air RA can be guided to the underfloor space 22. Thereby, since dry air can be actively guided to the underfloor space 22, it is possible to further suppress the occurrence of dew condensation in the connection duct 51, the branch chamber 52, and the air-conditioning ducts 53 to 55. Further, the fan 42 is a blowing means for generating an air flow toward the heat exchanger 41 inside the air passage 35. Such a blowing means is generally provided in an air conditioner. That is, while utilizing the general configuration of the air conditioner, the above-described effects are obtained.

[0080] · In the above-described first embodiment, the connection port 65 is provided on the downstream side of the fan 42 and on the upstream side of the heat exchanger 41 in the air passage 35. Further, when the shutter 66 is in the fully open position or the half-open position, its upper surface is configured to block a part of the flow of the return air RA. Thereby, a part of the return air RA taken into the indoor unit 32 can be smoothly guided to the return air guiding member 61.

[0081] · The return air RA led to the under-floor space 22 is only a part of the return air RA taken into the indoor unit 32, and the remaining return air RA becomes conditioned air. Therefore, while leading the return air RA to the under-floor space 22, the air conditioning of the living rooms 14 to 16 can be continued.

[0082] · The indoor unit 32 and the under-floor space 22 are connected via a return air guiding member 61. For this reason, when the indoor unit 32 stops the air conditioning operation, there is a concern that the air in the under-floor space 22 may flow backward toward the indoor unit 32, or insects or the like in the under-floor space 22 may enter the indoor unit 32. However, according to the first embodiment, when the indoor unit 32 stops the air conditioning operation, the shutter 66 is configured to take the closed position, so that such a problem can be suppressed.

[0083] · In the branch chamber 52 to which the plurality of air conditioning ducts 53 to 55 are connected, the conditioned air flowing through each of the air conditioning ducts 53 to 55 flows, so it is considered that the outer surface is likely to become low in temperature and condensation is likely to occur. Also, in the connection duct 51, it is similarly considered that condensation is likely to occur. Therefore, in the first embodiment, the return air RA is guided around the connection duct 51 and the branch chamber 52 through the return air guiding member 61. Thereby, it is possible to suitably suppress the occurrence of condensation in the connection duct 51 and the branch chamber 52.

[0084] · In a portion where the plurality of air conditioning ducts extend in the same direction in close proximity to each other, the surrounding air is likely to be cooled, and therefore it is considered that condensation is likely to occur. Therefore, in the first embodiment, the return air RA is guided around the duct parallel arrangement portion 57 through the return air guiding member 61. Thereby, it is possible to suitably suppress the occurrence of condensation in the duct parallel arrangement portion 57.

[0085] · When it is desired to rapidly advance the air conditioning of each of the rooms 14 to 16, it is conceivable to increase the amount of conditioned air (supply air SA) supplied to each of the rooms 14 to 16. However, if the amount of return air RA led to the underfloor space 22 is large, there is a risk that the return air RA for generating the conditioned air will be insufficient, and the rooms 14 to 16 may not be sufficiently air-conditioned. On the other hand, if the amount of return air RA led to the underfloor space 22 is small, there is a risk that condensation cannot be suppressed in the underfloor space 22. Therefore, according to the first embodiment, a shutter 66 is provided at the connection port 65 so as to be openable and closable, and by controlling the opening and closing of the shutter 66, the amount of return air RA led to the underfloor space 22 can be adjusted. Thereby, according to the temperature situation of the rooms 14 to 16 and the condensation situation of the underfloor space 22, the amount of return air RA led to the underfloor space 22 can be adjusted to an appropriate amount.

[0086] · Also, in the first embodiment, the room temperature of each of the rooms 14 to 16 is acquired by the room temperature sensor 75. And based on the room temperature of each of the rooms 14 to 16, the opening and closing control of the shutter 66 is performed. Thereby, when the temperature of the rooms 14 to 16 becomes high in summer, the generation of the conditioned air can be promoted by reducing the amount of return air RA led to the underfloor space 22. Thereby, the rooms 14 to 16 can be quickly cooled.

[0087] Specifically, when at least any one of the room temperatures of the rooms 14 to 16 exceeds a predetermined temperature T2, that is, when the rooms 14 to 16 are hot and it is desired to quickly cool the rooms 14 to 16, the shutter 66 is set to the closed position to stop leading the return air RA to the underfloor space 22. Thereby, it is possible to suppress the insufficient amount of the supply air SA led, and the cooling of the rooms 14 to 16 can be advanced with all efforts.

[0088] When at least one of the room temperatures of each of the rooms 14 to 16 is higher than a predetermined temperature T1 and all of the room temperatures of each of the rooms 14 to 16 are equal to or lower than a predetermined temperature T2, that is, when the cooling of the rooms 14 to 16 has progressed to a certain extent, the shutter 66 is set to the semi-open position, and the introduction of the return air RA to the underfloor space 22 is started in the second return air guiding mode. In the second return air guiding mode, the amount of the return air RA guided to the underfloor space 22 is limited compared to the first return air guiding mode. Thereby, while advancing the cooling of the rooms 14 to 16, the suppression of condensation in the underfloor space 22 can also be advanced. Also, since the predetermined temperature T2 is set to a temperature at which the occupants in the rooms 14 to 16 do not feel uncomfortable, even if the progress of the air conditioning is slightly delayed, there is no problem up to that point.

[0089] When all of the room temperatures of each of the rooms 14 to 16 become equal to or lower than the predetermined temperature T1, that is, when the cooling of the rooms 14 to 16 is completed, the shutter 66 is set to the fully open position and switched to the first return air guiding mode. In the first return air guiding mode, the amount of the return air RA guided to the underfloor space 22 is maximized. At this stage, since it is only necessary to maintain the room temperatures of the rooms 14 to 16, the required amount of the supply air SA is relatively small. For this reason, the suppression of condensation in the underfloor space 22 is carried out with all efforts.

[0090] ·When condensation actually occurs in the underfloor space 22, it is desirable to quickly eliminate the condensation. Therefore, in the above-described first embodiment, the condensation detection sensor 76 is configured to detect whether condensation has occurred in the underfloor space 22 (specifically, the duct parallel arrangement portion 57). And when the occurrence of condensation is detected, even if all of the room temperatures of each of the rooms 14 to 16 are higher than the predetermined temperature T2, the introduction of the return air RA to the underfloor space 22 is executed. In this case, since it is highly necessary to carry out both the cooling of the rooms 14 to 16 and the suppression of condensation in the underfloor space 22, the air conditioning system 30 is configured to take the second return air guiding mode. Thereby, while advancing the cooling of the rooms 14 to 16, the elimination of the condensation generated in the underfloor space 22 can be achieved.

[0091] ·The operating mode of the air conditioning system 30 can also be switched by the occupant operating the operation unit 72 of the remote control 71. As a result, the occupant can select an appropriate operating mode based on their own judgment.

[0092] (Second Embodiment) Next, the second embodiment will be described with reference to FIG. 4. Hereinafter, the description will focus on the differences from the first embodiment.

[0093] In the second floor portion 81 of the building 10, a plurality of living rooms 82 to 84 are provided. The living rooms 82 to 84 are arranged in a row in the east-west direction, specifically, in the order of living room 82, living room 83, and living room 84 from the west side to the east side. The living rooms 82 to 84 are partitioned from each other by partition walls 85, but are always ventilable between adjacent living rooms through door undercuts 86 and the like. Further, the building 10 has a roof portion 92 above the second floor portion 81 and a veranda 93 outside the living room 82.

[0094] In the second floor portion 81, a ceiling portion 91 is provided, and the ceiling surfaces of the living rooms 82 to 84 are formed by this ceiling portion 91. Further, the ceiling portion 91 is configured to have a ceiling surface material. Above the ceiling portion 91, a soffit space 94 of the roof portion 92 is formed. Note that the soffit space 94 corresponds to the soffit space.

[0095] The building 10 is provided with an air conditioning system 100 that performs air conditioning on each of the living rooms 82 to 84 in the second floor portion 81 as air conditioning targets. Hereinafter, the configuration of this air conditioning system 100 will be described. Note that each of the living rooms 82 to 84 corresponds to a "living space" that is air-conditioned by the air conditioning system.

[0096] The air conditioning system 100 is a heat pump type air conditioning system, similar to the air conditioning system 30, and is capable of performing at least cooling operation and heating operation. The air conditioning system 100 has an indoor unit 102 installed indoors and an outdoor unit 103 installed on the veranda 93. Similar to the air conditioning system 30, the indoor unit 102 and the outdoor unit 103 are connected via a refrigerant pipe 104, which is shown as a dotted line in FIG. 4 for convenience.

[0097] The indoor unit 102 is installed in the crawl space 94. The indoor unit 102 is located directly above the partition wall 85 provided between the living rooms 82 and 83. A branch chamber 106 is attached to the side plate portion of the indoor unit 102, and the inside of the indoor unit 102 and the inside of the branch chamber 106 communicate with each other. A plurality of air conditioning ducts 111 to 113 are connected to the branch chamber 106. The air conditioning duct 111 extends toward the living room 82, the air conditioning duct 112 extends toward the living room 83, and the air conditioning duct 113 extends toward the living room 84. That is, the air conditioning ducts 112 and 113 extend in the same direction. In FIG. 4, for convenience, the air conditioning duct 113 is shown as if it exists above the air conditioning duct 112, but actually, the air conditioning ducts 111 to 113 are all laid on the bottom surface of the crawl space 94.

[0098] An air supply outlet 117 provided in the ceiling portion 91 of each of the living rooms 82 to 84 is connected to each of the air conditioning ducts 111 to 113. The conditioned air generated by the indoor unit 102 is blown out as supply air SA into each of the living rooms 82 to 84 from each air supply outlet 117. Thereby, air conditioning (heating and cooling) of each of the living rooms 82 to 84 is performed.

[0099] In the building 10, as described above, the living rooms 82 to 84 can be constantly ventilated through the door undercut 86. For this reason, the conditioned air (supply air SA) supplied to the living rooms 83 and 84 flows into the living room 82 through the door undercut 86.

[0100] In the ceiling portion 91 of the living room 82, an air return intake port 118 is provided. The air return intake port 118 is connected to the indoor unit 102 via the air return duct 119. Thereby, the indoor unit 102 can take in the air in the living room 82 as the air return RA into the indoor unit 102. That is, the supply air SA supplied to the living rooms 83 and 84 returns (flows back) to the indoor unit 102 as the air return RA together with the supply air SA supplied to the living room 82. The indoor unit 102 regenerates the conditioned air based on the returned air return RA. Thus, also for the air conditioning system 100, like the air conditioning system 30, it is a circulation type air conditioning system.

[0101] Note that the indoor unit 102 has a fan and a heat exchanger (not shown), similar to the indoor unit 32. The indoor unit 102 adjusts the temperature of the air return RA taken into it by the heat exchanger to generate conditioned air.

[0102] In each of the air conditioning ducts 112 and 113, a predetermined length portion (hereinafter referred to as the predetermined length portions 112a and 113a) extending from the branch chamber 106 extends in the same direction at positions close to each other. In this case, these predetermined length portions 112a and 113a constitute a duct parallel arrangement portion 115. Specifically, each of the predetermined length portions 112a and 113a constituting the duct parallel arrangement portion 115 extends in a substantially straight line and is parallel to each other.

[0103] Here, also in the attic space 94, similar to the case of the first embodiment, when the air conditioning system 100 is in cooling operation in summer, there is a concern that condensation may occur in the duct parallel arrangement portion 115 and the branch chamber 106. For this reason, the indoor unit 102 is provided with an air return guiding member 121 that guides a part of the air return RA taken into the indoor unit 102 into the attic space 94 during the air conditioning operation of the air conditioning system 100.

[0104] The air return guiding member 121 is composed of pipes 121a, 121b, 121c which are hollow pipes and a hollow T-shaped pipe 121d.

[0105] Specifically, the pipes 121a and 121b are straight tubular, and the pipe 121c is bent in an L shape. One end of the pipe 121a is connected to the side plate portion on the side of the branch chamber 106 of the indoor unit 102, and it extends straight along the air conditioning ducts 112 and 113. A T-shaped pipe 121d is attached to the other end of the pipe 121a. The T-shaped pipe 121d is located directly above the branch chamber 106, and in addition to the pipe 121a, the pipe 121b and the pipe 121c are connected to the T-shaped pipe 121d. The pipe 121b extends straight downward from the T-shaped pipe 121d. A return air outlet 122 for blowing out the return air RA is formed at the open end of the pipe 121b. Therefore, the return air guiding member 121 can blow the return air RA from above toward the branch chamber 106 from the return air outlet 122.

[0106] Also, the pipe 121c extends straight along the air conditioning ducts 112 and 113 from the T-shaped pipe 121d. A return air outlet 123 for blowing out the return air RA is formed at the open end of the pipe 121c. A bending portion 121e is provided at a portion of the pipe 121c located directly above the duct parallel arrangement portion 115. Due to this bending portion 121e, the return air outlet 123 is in a state facing the duct parallel arrangement portion 115 from the return air outlet 123. Therefore, the return air guiding member 121 can blow the return air RA from above toward the duct parallel arrangement portion 115 from the return air outlet 123.

[0107] That is, the return air guiding member 121 branches at its middle portion (specifically, the portion located directly above the branch chamber 106) and forms an F shape as a whole. The return air guiding member 121 has two return air outlets 122 and 123, and is configured to blow the return air RA from each of the return air outlets 122 and 123 toward the branch chamber 106 and the duct parallel arrangement portion 115, respectively.

[0108] Note that in the air conditioning system 100, components corresponding to the adjustment means, control means, temperature detection means, and dew condensation detection means are not provided, and the configuration is simpler than that of the air conditioning system 100. That is, the adjustment means, control means, temperature detection means, and dew condensation detection means are not essential components.

[0109] According to the configuration of the second embodiment described in detail above, the following excellent effects can be obtained.

[0110] · The air conditioning system 100 targets the second floor part 81 for air conditioning, and the indoor unit 102 is installed in the attic space 94. Further, the air conditioning ducts 111 to 113 are arranged in the attic space 94. The return air RA is considered to be drier than the air in the attic space 94 even before being temperature-adjusted by the indoor unit 102. Therefore, even in such a configuration, by guiding a part of the return air RA to the attic space 94 by the return air guiding member 121, it is possible to suppress the occurrence of dew condensation on the air conveyance members arranged in the attic space 94.

[0111] · The return air guiding member 121 has two return air outlets 122 and 123, and blows the return air RA against the duct parallel arrangement part 115 and the branch chamber 106, respectively. Thereby, it is possible to preferably suppress the occurrence of dew condensation in the duct parallel arrangement part 115 and the branch chamber 106.

[0112] The present invention is not limited to the above embodiments, and may be implemented, for example, as follows.

[0113] (a) In the above first and second embodiments, the elimination of problems in summer is exemplified. However, even in winter, in the back space of the building 10, there is a concern that problems related to the air environment may occur. For example, in the underfloor space 22 and the attic space 94, cold air tends to accumulate. And there is a concern that the living rooms 14 to 16 and 82 to 84 may be cooled through the floor part 21 and the ceiling part 91 by the cold air accumulated in the underfloor space 22 and the attic space 94.

[0114] However, in the above-described first and second embodiments, a part of the return air RA is introduced into the underfloor space 22 and the attic space 94 by the return air guiding members 61 and 121. The return air RA is considered to be at a higher temperature than the air in the underfloor space 22 and the attic space 94 during the heating operation of the air conditioning systems 30 and 100. Therefore, the air in the underfloor space 22 and the attic space 94 can be heated up.

[0115] Also, when the air conditioning system is in the heating operation, due to the influence of the high-temperature conditioned air flowing inside the air conveyance member, the air around the air conveyance member becomes relatively high-temperature. In particular, such a phenomenon becomes prominent around the portion where the air conditioning ducts are arranged side by side and around the branch chamber. Here, in the above-described first and second embodiments, the return air RA is blown onto the connection duct 51, the branch chambers 52 and 106, and the duct parallel arrangement portions 57 and 115 by the return air guiding members 61 and 121. As a result, the relatively high-temperature air existing around the connection duct 51, the branch chambers 52 and 106, and the duct parallel arrangement portions 57 and 115 can be diffused, so that the underfloor space 22 and the attic space 94 can be heated up as a whole. Therefore, the above-mentioned problems in winter can be suppressed.

[0116] (b) In the above-described first embodiment, the room temperature sensors 75 are provided in each of the rooms 14 to 16, and the shutters 66 are controlled based on the acquisition results of the room temperature sensors 75. However, the control method of the shutters 66 is not limited to this. For example, instead of the room temperature sensors 75 in the rooms 14 to 16, a temperature and humidity sensor may be provided in the underfloor space 22, and control may be performed based on the acquisition results of the temperature and humidity sensor. Specifically, in summer, it is considered that the higher the temperature and humidity of the air in the underfloor space 22, the more likely problems such as condensation occur in the underfloor space 22. Therefore, a predetermined threshold value is set for the temperature and humidity in the underfloor space 22, and when the temperature and humidity acquired by the temperature and humidity sensor exceed the predetermined threshold value, a configuration is conceivable in which the opening and closing control of the shutter 66 is performed so as to more actively guide the return air RA into the underfloor space 22. Thereby, it is possible to suppress the occurrence of condensation in the air conveyance member.

[0117] (c) The shutter 66 may be manually openable and closable by the occupant. In this case, since the room temperature sensor 75 and the drive unit 68 can be omitted, the configuration can be simplified.

[0118] (d) The arrangement of each living space is not particularly limited. However, if a plurality of living spaces are arranged in the same direction as viewed from the indoor unit, an arrangement of air-conditioning ducts is likely to occur in which a plurality of air-conditioning ducts are close to each other and extend in the same direction. For this reason, problems such as condensation are likely to occur.

[0119] (e) The configuration of the indoor unit is not limited to the configurations of the first and second embodiments described above, and any configuration may be used as long as the return air RA before heat exchange can be appropriately introduced into the return air guiding means.

[0120] (f) The configuration of the return air guiding means is not limited to the configurations of the first and second embodiments described above. The shape of the return air guiding means and the number of return air outlets provided in the return air guiding means are not limited. Also, a plurality of return air guiding means may be provided.

[0121] (g) The guiding destination of the return air RA by the return air guiding members 61 and 121 is not limited to the connection duct 51, the branch chambers 52 and 106, and the duct juxtaposition portions 57 and 115. For example, it may be introduced into a location where no other air-conditioning duct is provided nearby, such as the air-conditioning ducts 53 and 111. Also, the return air guiding members 61 and 121 do not necessarily have to blow the return air RA aiming at a specific location, and if the return air RA can be introduced into the back space, the occurrence of condensation in the back space can be suppressed.

[0122] (h) It is not essential to provide a return air guiding member in the indoor unit. For example, when the configuration is such that at least a part of the indoor unit exists in the back space, an opening may be provided in the part of the housing of the indoor unit that is located inside the back space, and a configuration may be considered in which the return air RA inside the housing can be discharged to the outside of the housing through the opening. Even with such a configuration, the return air RA can be guided into the back space. In this case, the opening corresponds to the return air guiding means.

[0123] (i) The air conditioning system is not limited to one floor and may be for the entire building 10.

[0124] (j) Some air conditioning systems can perform dehumidification operation. In such an air conditioning system, when performing dehumidification operation, the indoor unit may generate cooling air. In that case, condensation may occur in the air conditioning duct or the like even during dehumidification operation. In that case, according to the above first and second embodiments using the return air guiding members 61 and 121, it is possible to suppress condensation from occurring in the air conveying member or the like even during dehumidification operation.

Explanation of reference numerals

[0125] 10…Building, 14 - 16…Bedrooms as living spaces, 22…Underfloor space as a back space, 30…Air conditioning system, 32…Indoor unit as an air conditioner, 35…Air passage, 41…Heat exchanger as a heat exchange section, 42…Fan as a blowing means, 51…Connection duct, 52…Branch chamber, 53 - 55…Air conditioning ducts, 57…Duct parallel arrangement section, 61…Return air guiding member as a return air guiding means, 66…Shutter as an adjustment means, 70…Controller as a control means, 75…Room temperature sensor as a temperature detection means, 76…Dew condensation sensor as a dew condensation detection means.

Claims

1. Applied to a building having a plurality of living spaces and a back space which is a space under the floor or in the attic of the living space, An air conditioner capable of at least cooling operation, and generating air-conditioned air for cooling during the cooling operation, An air conveyance member disposed in the back space and conveying the air-conditioned air generated by the air conditioner to each living space, The air-conditioned air conveyed to each living space is configured to return to the air conditioner, The air conditioner is an air conditioning system of a building that takes in the returned air as return air and generates air-conditioned air by exchanging heat between the return air and a refrigerant, The air conditioning system includes a return air guiding means for guiding a part of the return air taken into the air conditioner to the back space without performing the heat exchange, The air conditioner has an air passage for sending the return air taken into the air conditioner to a heat exchange section that performs the heat exchange, and a blowing means for generating a flow of air toward the heat exchange section in the air passage, The return air guiding means is characterized in that it guides a part of the return air from a position downstream of the blowing means and upstream of the heat exchange section in the air passage to the back space.

2. Applied to a building having a plurality of living spaces and a back space which is a space under the floor or in the attic of the living space, An air conditioner capable of at least cooling operation, and generating air-conditioned air for cooling during the cooling operation, An air conveyance member disposed in the back space and conveying the air-conditioned air generated by the air conditioner to each living space, The air-conditioned air conveyed to each living space is configured to return to the air conditioner, The air conditioner is an air conditioning system of a building that takes in the returned air as return air and generates air-conditioned air by exchanging heat between the return air and a refrigerant, The air conditioning system includes a return air guiding means for guiding a part of the return air taken into the air conditioner to the back space without performing the heat exchange, As the air conveyance member, it has a branch chamber connected to the air conditioner and a plurality of air ducts connected to the branch chamber, The air-conditioned air generated by the air conditioner is conveyed to each living space through the branch chamber and each air duct, The return air guiding means is a tubular return air guiding member that extends from the air conditioner to the back space and guides a part of the return air to the back space through its interior. The building air conditioning system is characterized in that the air return guiding member guides a part of the air return around the branch chamber.

3. In the back space, a duct parallel arrangement part is provided where a plurality of the air conditioning ducts extend in the same direction at positions close to each other. The building air conditioning system according to claim 2, wherein the air return guiding member guides a part of the air return to the duct parallel arrangement part.

4. Applied to a building having a plurality of living spaces and a back space which is a space under the floor or in the attic of the living space. An air conditioning apparatus capable of at least cooling operation, and generating air conditioning air for cooling during the cooling operation. An air conveyance member disposed in the back space and conveying the air conditioning air generated by the air conditioning apparatus to each living space. The air conditioning air conveyed to each living space is refluxed to the air conditioning apparatus. The air conditioning apparatus is a building air conditioning system that takes in the refluxed air as air return, and generates air conditioning air by exchanging heat between the air return and a refrigerant. It includes an air return guiding means for guiding a part of the air return taken into the air conditioning apparatus to the back space without performing the heat exchange. The air conditioning apparatus has an adjustment means for adjusting the amount of the air return guided from the air conditioning apparatus to the back space by the air return guiding means. Temperature detection means for detecting the temperature of the living space. Control means for controlling the adjustment means. The building air conditioning system is characterized in that the control means controls the adjustment means based on the temperature of the living space detected by the temperature detection means.

5. It includes dew condensation detection means for detecting that dew condensation has occurred in the back space. The building air conditioning system according to claim 4, wherein the control means controls the adjustment means so that the amount of the air return guided to the back space increases when the dew condensation detection means detects the occurrence of dew condensation.

6. The air conditioning apparatus has an air passage for sending the air return taken into the air conditioning apparatus to a heat exchange part that performs the heat exchange, and a blowing means for generating a flow of air toward the heat exchange part in the air passage. The building air conditioning system according to any one of claims 2 to 5, wherein the air return guiding means guides a part of the air return to the back space from a position downstream of the blowing means and upstream of the heat exchange part in the air passage.

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