Simultaneous supply / discharge type ventilation device

Abstract

A simultaneous supply / discharge type ventilation device (101) comprises: a supply air blower (3) that forms a supply air flow in a supply air passage; an exhaust air blower (2) that forms an exhaust air flow in an exhaust air passage; a first heat exchanger (4) that is installed within an outer shell casing (1), straddling the supply air passage and the exhaust air passage, and that performs heat exchange between the supply air flow and the exhaust air flow; a second heat exchanger (5) that is installed in the supply air passage and that is provided with a refrigerant circuit for heating or cooling air passing through the supply air passage; a refrigerant detecting sensor (6) that is installed in the supply air passage to detect refrigerant that has leaked from the refrigerant circuit into the supply air passage; an air passage switching damper unit (7) that discharges refrigerant that has leaked into the supply air passage to the outside; and a control unit (8) that controls the operation of the supply air blower and the exhaust air blower, and operates the air passage switching damper unit (7) if the refrigerant detecting sensor detects a refrigerant concentration equal to or greater than a preset reference value.

Description

Simultaneous supply / exhaust ventilation system

[0001] The present disclosure relates to a simultaneous supply and exhaust ventilation system equipped with a heat exchanger having a refrigerant circuit using a slightly flammable refrigerant or a flammable refrigerant.

[0002] A conventional ventilation air-conditioning system includes an air conditioner having a heat exchanger that generates conditioned air by heat exchange with a slightly flammable or flammable refrigerant, a refrigerant sensor for detecting refrigerant leaks in the air-conditioned space, a ventilation device that supplies air using a blower and exhausts air using a blower, and an auxiliary blower that is communicatively connected to the air conditioner and the ventilation device and that does not operate when the refrigerant sensor does not detect a refrigerant leak but operates when the refrigerant sensor detects a refrigerant leak. This ventilation air-conditioning system can increase the amount of air supplied to the living space, which is the air-conditioned space, by operating the auxiliary blower in addition to the ventilation device when the refrigerant sensor detects a refrigerant leak. This dilutes the leaked refrigerant and prevents the refrigerant from reaching a flammable concentration (see, for example, Patent Document 1).

[0003] Furthermore, conventional ventilation and air conditioning systems are equipped with a supply air duct formed through a supply air (SA) duct that supplies air indoors from an outdoor air (OA) duct that takes in air from outdoors, and an exhaust air duct formed through an exhaust air (EA) duct that exhausts air outdoors from a return air (RA) duct that draws air from indoors, and a first heat exchanger that exchanges heat between the airflows flowing through the supply air duct and the exhaust air duct, and further equipped with a second heat exchanger downstream of the first heat exchanger in the supply air duct that has a refrigerant circuit that heats or cools the airflow flowing through the supply air duct, thereby achieving both ventilation and air conditioning (see, for example, Patent Document 2).

[0004] The non-flammable refrigerant R410A is primarily used as a refrigerant in conventional air conditioners and air conditioning systems. However, due to the high global warming potential of R410A, the mildly flammable refrigerant R32 or the flammable refrigerant R290, which have low global warming potential, are increasingly being used instead of R410A. When using mildly flammable or flammable refrigerants, it is mandatory to install a gas sensor to monitor refrigerant leakage, and measures must be taken to prevent indoor refrigerant concentrations from exceeding standard values ​​in the event of a refrigerant leak.

[0005] JP 2020-183829 A Patent No. 5591329 A

[0006] In either of the conventional ventilation air conditioning systems or ventilation air conditioning devices described above, if refrigerant leaks from a heat exchanger having an internal refrigerant circuit, there is a problem in that the leaked refrigerant mixes with the intake air flow and is released into the space to be air-conditioned.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a simultaneous supply and exhaust type ventilation device that can discharge refrigerant leaking into the air-conditioned space to the outdoors without supplying it indoors, even if a slightly flammable or flammable refrigerant leaks from a heat exchanger having a refrigerant circuit.

[0008] In order to solve the above-mentioned problems and achieve the object, the simultaneous supply and exhaust ventilation device according to the present disclosure includes a casing provided with an air intake port that takes in outdoor air, an air intake outlet that supplies outdoor air indoors, an exhaust air intake port that draws in indoor air, an exhaust outlet that discharges indoor air to the outside, an air intake duct connecting the air intake port and the air intake outlet, and an exhaust duct connecting the exhaust air intake port and the exhaust outlet, an air intake fan installed in the air intake duct and forming an air intake flow in the air intake duct, an exhaust fan installed in the exhaust duct and forming an exhaust flow in the exhaust duct, and a casing provided with: an air intake duct; the first heat exchanger is installed in the casing across the intake air duct and exchanges heat between the intake air flow and the exhaust air flow; a second heat exchanger is installed in the intake air duct and has a refrigerant circuit that heats or cools the air passing through the intake air duct; a refrigerant detection sensor is installed in the intake air duct and detects refrigerant that has leaked from the refrigerant circuit into the intake air duct; leaked refrigerant discharge means that discharges refrigerant that has leaked into the intake air duct to the outdoors; and a control unit that controls the operation of the intake air blower and the exhaust air blower and operates the leaked refrigerant discharge means when the refrigerant detection sensor detects a refrigerant concentration that is equal to or higher than a predetermined reference value.

[0009] The simultaneous supply and exhaust ventilation system of the present disclosure has the advantage that even if a slightly flammable or flammable refrigerant leaks from a heat exchanger having a refrigerant circuit, the refrigerant that leaks into the air-conditioned space can be discharged outdoors without being supplied indoors.

[0010] Schematic diagram showing the damper position during normal operation of a simultaneous supply and exhaust ventilation system according to embodiment 1. Schematic diagram of a cross section of a simultaneous supply and exhaust ventilation system according to embodiment 1. Schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to embodiment 1. Schematic diagram showing the damper position during normal operation of a simultaneous supply and exhaust ventilation system according to a first modified example of embodiment 1. Schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to a first modified example of embodiment 1. Schematic diagram showing the damper position during normal operation of a simultaneous supply and exhaust ventilation system according to a second modified example of embodiment 1. Schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to a second modified example of embodiment 1. Schematic diagram showing the damper position during normal operation of a simultaneous supply and exhaust ventilation system according to embodiment 2. Schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to embodiment 2. Schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to a modified example of embodiment 2.

[0011] A simultaneous supply and exhaust ventilation system according to an embodiment will be described in detail below with reference to the drawings.

[0012] Embodiment 1. A simultaneous supply and exhaust ventilation system 101 according to Embodiment 1 will be described with reference to Figures 1, 2, and 3. Figure 1 is a schematic diagram showing the damper position during normal operation of the simultaneous supply and exhaust ventilation system according to Embodiment 1. Figure 1 shows the damper position during normal operation when no refrigerant leakage has been detected. Figure 2 is a schematic diagram of a cross section of the simultaneous supply and exhaust ventilation system according to Embodiment 1. Figure 3 is a schematic diagram showing the damper position when a refrigerant leakage is detected in the simultaneous supply and exhaust ventilation system according to Embodiment 1. The side of the outer casing 1 is provided with an air intake port 11 to which an external outside air duct 21 is connected, an air intake port 12 to which an external supply air duct 22 is connected, an exhaust air intake port 13 to which an external return air duct 23 is connected, and an exhaust air outlet 14 to which an external exhaust duct 24 is connected. The supply air blower 3 is operated to draw outdoor air from the supply air inlet 11 via the external outside air port 31 and the outside air duct 21, and the air passes through the first heat exchanger 4 and the second heat exchanger 5 having a refrigerant circuit, through the supply air outlet 12, the supply air duct 22, and is supplied indoors from the external supply air inlet 32. The air path from the supply air inlet 11 to the supply air outlet 12 is an air supply path formed inside the simultaneous supply and exhaust ventilation device 101. The exhaust air blower 2 is operated to draw indoor air from the exhaust inlet 13 via the external return air port 33 and the return air duct 23, and the air is then discharged outdoors through the first heat exchanger 4, the exhaust outlet 14, the exhaust duct 24, and the external exhaust port 34. The air path from the exhaust inlet 13 to the exhaust outlet 14 is an exhaust air path formed inside the simultaneous supply and exhaust ventilation device 101. In the first heat exchanger 4, heat is exchanged between the outdoor air drawn in by the intake fan 3 and passing through the intake air duct, and the indoor air drawn in by the exhaust fan 2 and passing through the exhaust air duct. Furthermore, since the second heat exchanger 5 is provided downstream of the intake fan 3, the outdoor air that has been drawn in exchanges heat with the refrigerant flowing through the refrigerant circuit as it passes through the second heat exchanger 5, and the air is conditioned by temperature control and supplied to the room.

[0013] In recent years, in response to greenhouse gas reduction efforts, the refrigerant circuit connected to the second heat exchanger 5 has been replaced by either the mildly flammable refrigerant R32 or the flammable refrigerant R290, both of which have low global warming potentials, instead of the non-flammable refrigerant R410A, which has a high global warming potential. Because the refrigerant is either mildly flammable or flammable, it is mandatory to install a refrigerant detection sensor 6 near the second heat exchanger 5. The refrigerant detection sensor 6 measures the refrigerant gas concentration in the supply air duct to detect whether the refrigerant used in the second heat exchanger 5 is leaking outside the second heat exchanger 5. The refrigerant detection sensor 6 is located in the supply air duct between the downstream side of the second heat exchanger 5 and the supply air outlet 12 so that refrigerant leakage can be detected even when the supply air blower 3 is operating. When the supply air blower 3 is stopped, the specific gravity of the refrigerant is high and any leaked refrigerant will accumulate below the second heat exchanger 5, so the refrigerant detection sensor 6 is positioned as low as possible in the supply air duct.

[0014] The refrigerant detection sensor 6 is a semiconductor sensor that utilizes the properties of a metal oxide semiconductor, and when the refrigerant to be measured comes into contact with the metal oxide semiconductor, oxygen in the metal oxide bonds with a component of the refrigerant, changing the resistance of the metal oxide to measure the concentration. Note that the refrigerant detection sensor 6 is not limited to a semiconductor sensor as long as it can detect the refrigerant, and may be, for example, an infrared sensor that uses non-dispersive infrared absorption (NDIR).

[0015] The control unit 8 issues instructions to stop or start the supply air blower 3 and change its air speed, to stop or start the exhaust air blower 2 and change its air speed, and to operate the exhaust air-channel switching damper 9. Furthermore, when the refrigerant detection sensor 6 detects that refrigerant is leaking from the second heat exchanger 5, the control unit 8 operates the leaked refrigerant discharge means to discharge the leaked refrigerant outdoors without supplying it indoors. In the simultaneous supply and exhaust type ventilation device 101 according to the first embodiment, the leaked refrigerant discharge means is the air-channel switching damper 7.

[0016] The air-path switching damper unit 7 is composed of a first damper 71, a second damper 72, and damper drivers 74 and 75. The first damper 71 is an air-path communication damper that is attached to the damper driver 74 and rotates to open the air-path communication passage 10 connecting the supply air path and the exhaust air path of the simultaneous supply and exhaust ventilation device 101 and close the exhaust air inlet 13. The damper driver 74 operates in response to instructions from the control unit 8. The second damper 72 is an air-supply shutoff damper that is attached to the damper driver 75 and rotates to close the supply air outlet 12. The damper driver 75, like the damper driver 74, operates in response to instructions from the control unit 8. The damper drivers 74 and 75 each have an independent motor and are controlled by the control unit 8 so that the first damper 71 and the second damper 72 rotate simultaneously.

[0017] Next, the operation when a refrigerant leak is detected will be described. When the simultaneous supply and exhaust ventilation system 101 is started, the control unit 8 operates the simultaneous supply and exhaust ventilation system 101 in normal operation. During normal operation, the exhaust fan 2 and the supply fan 3 are operated to perform ventilation, the air path switching damper unit 7 is not operated, the first damper 71 operates with the air path communication passage 10 closed and the exhaust intake port 13 open, and the second damper 72 operates with the supply air outlet 12 open.

[0018] The refrigerant concentration in the supply air duct is periodically measured by the refrigerant detection sensor 6, and if the measured refrigerant concentration is equal to or less than a preset reference value, the control unit 8 determines that refrigerant is not leaking into the supply air duct and maintains a normal operating state without operating the air duct switching damper unit 7. That is, the first damper 71 keeps the air duct communication passage 10 closed and the exhaust air inlet 13 open, and the second damper 72 keeps the supply air outlet 12 open.

[0019] On the other hand, if the refrigerant detection sensor 6 detects a refrigerant concentration equal to or greater than a predetermined reference value, the control unit 8 determines that a refrigerant leak has occurred and issues an operation command to the air-path switching damper unit 7. Upon receiving the operation command, the air-path switching damper unit 7 operates the damper drivers 74 and 75. The damper driver 74 rotates the first damper 71 attached to the damper driver 74 to open the air-path communication passage 10 and connect the supply air path and the exhaust air path. At this time, the first damper 71 is moved by the damper driver 74 to a position that closes the exhaust air inlet 13. This operation prevents refrigerant from leaking into the room through the exhaust air inlet 13, which is connected to the room via the return air duct 23. The damper driver 75 operates simultaneously with the damper driver 74 to move the second damper 72 attached to the damper driver 75 to a position that closes the supply air outlet 12. This operation prevents refrigerant from leaking into the room from the supply air outlet 12, which is connected to the room by the supply air duct 22. The positions of the first damper 71 and the second damper 72 when refrigerant is leaking are shown in Figure 3. By changing the positions of the first damper 71 and the second damper 72 as shown in Figure 3, the supply air duct and the exhaust air duct are connected, and both the supply air outlet 12 and the exhaust air inlet 13, which are connected to the room by ducts, are closed, thereby isolating the supply air duct and the exhaust air duct from the room.

[0020] Furthermore, when the control unit 8 operates the air path switching damper unit 7, it also operates the exhaust air path switching damper 9 provided in the simultaneous supply and exhaust type ventilation device 101, switching from heat exchange ventilation in which the airflow in the exhaust air path passes through the first heat exchanger 4 as shown by the arrow Fea in Fig. 1 during normal operation to bypass ventilation in which the airflow in the exhaust air path does not pass through the first heat exchanger 4 as shown by the arrow Fea in Fig. 3, so that the exhausted refrigerant does not pass through the first heat exchanger 4. This prevents the supply air flow containing leaked refrigerant from returning to the supply air path when it passes through the first heat exchanger 4.

[0021] The simultaneous supply and exhaust ventilation system 101 according to the first embodiment includes a second heat exchanger 5 that uses a mildly flammable refrigerant or a flammable refrigerant, and when the refrigerant detection sensor 6 detects a refrigerant concentration equal to or higher than a preset reference value, the air path switching damper 7 is operated to connect the supply air path and the exhaust air path, thereby discharging the mildly flammable refrigerant or flammable refrigerant that has leaked into the supply air path to the outdoors. This prevents the accumulation or high concentration of mildly flammable refrigerant inside the simultaneous supply and exhaust ventilation system 101 and the room, and further reduces the risk of fire due to high concentrations.

[0022] Modification of Embodiment 1 Although the air-path switching damper unit 7 according to Embodiment 1 is configured to close the exhaust air intake port 13 when the first damper 71 opens the air-path communication passage 10, a third damper (not shown) that opens and closes the exhaust air intake port 13 may be provided separately from the first damper 71. The third damper opens the exhaust air intake port 13 when the air-path switching damper unit 7 is not operated, and closes the exhaust air intake port 13 when the air-path switching damper unit 7 is operated, thereby preventing leaked refrigerant from flowing back into the room through the return air port 33.

[0023] In addition, in FIG. 1, the air duct communication passage 10, which is opened and closed by the first damper 71, and the air intake outlet 12, which is opened and closed by the second damper 72, are positioned apart, so the first damper 71 and the second damper 72 are provided separately, but the air intake duct may be changed to a structure that can block the air intake outlet 12 when the air duct communication passage 10 is open, and the first damper 71 and the second damper 72 may be integrated.

[0024] Furthermore, in the simultaneous supply and exhaust ventilation system 101 according to the first embodiment, the air path switching damper unit 7 only needs to operate the damper drive units 74, 75 simultaneously. Therefore, a motor may be provided on one of the damper drive units 74, 75 and a pulley may be provided on the other. The damper drive units 74, 75 may be connected by an interlocking belt 73 to transmit the power of the motor, thereby interlocking the first damper 71 and the second damper 72. The interlocking belt 73 is preferably made of a non-slip material, such as rubber, to reliably transmit the power of the motor provided on one of the damper drive units 74, 75. Alternatively, a gear may be attached to the rotating shaft of the motor, and the interlocking belt 73 that contacts the gear may be a toothed belt whose inner surface is wavy to match the gear.

[0025] 4 and 5 are schematic diagrams illustrating the configuration of a simultaneous supply and exhaust ventilation system according to a first modification of the first embodiment. FIG. 4 illustrates the position of the air-path switching damper unit 7 during normal operation, and FIG. 5 illustrates the position of the air-path switching damper unit 7 when a refrigerant leak is detected. As shown in FIGS. 1 and 3 , the air-path switching damper unit 7 according to the first embodiment rotates both the first damper 71 and the second damper 72 to change the refrigerant discharge path. However, as shown in FIGS. 4 and 5 , the second damper 72 may be slid to close the supply and exhaust outlet 12. Possible methods for sliding the second damper 72 with the damper drive unit 75 include providing a non-slip roller on the rotating shaft of the damper drive unit 75 to prevent freewheeling and contacting the surface of the second damper 72 to slide the second damper 72, or providing a gear-shaped rotating shaft of the damper drive unit 75 and fixing a waveform-shaped part that matches the gear of the rotating shaft of the damper drive unit 75 to the surface of the second damper 72 to slide the second damper 72.

[0026] The simultaneous supply and exhaust ventilation device 101 equipped with the air path switching damper section 7 configured in this manner also has the effect of allowing the second damper 72 to close the air supply and exhaust outlet 12 in the event of a refrigerant leak, thereby discharging the leaked refrigerant outdoors without supplying it indoors.

[0027] In particular, even if there is not enough space for the second damper 72 to rotate, if the second damper 72 is designed to slide, it is possible to close the supply / discharge port 12 and discharge leaked refrigerant to the outdoors without supplying it indoors. Furthermore, since no operating space is required for the second damper 72, space can be saved and the simultaneous supply / discharge type ventilation device 101 can be made smaller.

[0028] Furthermore, the simultaneous supply and exhaust ventilation system 101 may be configured to open and close the air-path communication passage 10, the air supply outlet 12, and the exhaust inlet 13 with an integrally configured air-path switching damper unit 7. Figures 6 and 7 are diagrams showing the configuration of a simultaneous supply and exhaust ventilation system according to a second modification of Embodiment 1. Figure 6 shows the position of the air-path switching damper unit 7 during normal operation, and Figure 7 shows the position of the air-path switching damper unit 7 when a refrigerant leak is detected. In simultaneous supply and exhaust ventilation device 101 according to a variation of Embodiment 1, air-path switching damper unit 7, which is a leaking refrigerant discharge means, includes first slider unit 81 that moves between an intermediate portion between supply air outlet 12 and exhaust air inlet 13 and a first position directly facing supply air outlet 12, first plate unit 82 connected to first slider unit 81, second slider unit 84 that moves between the intermediate portion and a second position directly facing exhaust air inlet 13, and second plate units 83 connected to first plate unit 82 and second slider unit 84. First slider unit 81 and first plate unit 82 are rotatably connected by first hinge unit 85. First plate unit 82 and second plate unit 83 are rotatably connected by second hinge unit 86. The second plate portion 83 and the second slider portion 84 are rotatably connected by a third hinge portion 87 .

[0029] During normal ventilation, the air-path switching damper 7 is bent so that the first slider 81 and the second slider 84 are located in the middle and the first plate 82 and the second plate 83 overlap each other. As a result, the air-path communication passage 10 is blocked by the first plate 82 and the second plate 83, and the supply air path and the exhaust air path are separated.

[0030] When a refrigerant leak is detected, first slider 81 moves to the first position, and second slider 84 moves to the second position. This causes first slider 81, first plate 82, second plate 83, and second slider 84 to expand into flat plates, blocking supply air outlet 12 and exhaust air inlet 13, while opening air path communication passage 10 to connect the supply air path and the exhaust air path. As a result, any slightly flammable or flammable refrigerant leaking into the supply air path is exhausted to the outdoors via the exhaust air path.

[0031] As described above, even if refrigerant leaks from the second heat exchanger 5 in the intake air duct, the leaked refrigerant can be reliably discharged by the exhaust fan 2 provided in the outer casing 1. Furthermore, when the air path switching damper unit 7 operates, the intake air duct and the exhaust air duct are connected to each other, and at the same time, the connection ports of the intake air duct and the return air duct that communicate with the indoor side are blocked, thereby reliably preventing the leaked refrigerant from flowing into the room.

[0032] In addition, in the first embodiment, an example has been shown in which the refrigerant circuit provided in the second heat exchanger 5 uses either the slightly flammable refrigerant R32 or the flammable refrigerant R290, but the type of refrigerant is not limited to these.

[0033] In the first embodiment, the air-path switching damper unit 7, which is the leaking refrigerant discharge means, is composed of a first damper 71, a second damper 72, and damper drive units 74 and 75. When the air-path switching damper unit 7 is in operation, the first damper 71 attached to the damper drive unit 74 is rotated to open the air-path communication passage 10, thereby connecting the supply air path and the exhaust air path, and close the exhaust air inlet 13. The second damper 72 attached to the damper drive unit 75 closes the supply air outlet 12. However, a configuration has been shown in which the leaked refrigerant discharge means is provided with only the first damper 71 and the damper drive unit 74, and the first damper 71 is rotated when the leaked refrigerant discharge means is operating to open at least the air path connecting passage 10 to communicate between the supply air path and the exhaust air path. In this case, although it is not possible to completely isolate the supply air path from the room, a simple configuration can be used to discharge most of the refrigerant that has leaked into the supply air path to the outdoors.

[0034] Furthermore, in embodiment 1, when the air path switching damper unit 7, which is the leaked refrigerant discharge means, operates, the exhaust air path switching damper 9 is operated to switch to bypass ventilation in which the airflow in the exhaust air path does not pass through the first heat exchanger 4, so that the discharged refrigerant does not pass through the first heat exchanger 4. However, if the pressure loss in the air path of the bypass ventilation is smaller than the pressure loss in the heat exchange ventilation that passes through the first heat exchanger 4, and if there is no risk of gas components transferring in the first heat exchanger 4 from the exhaust air path mixed with the leaked refrigerant to the supply air path, it is possible to remain in heat exchange ventilation without switching to bypass ventilation.

[0035] Embodiment 2. Figure 8 is a schematic diagram showing the damper position during normal operation of a simultaneous supply and exhaust ventilation system according to embodiment 2. Figure 9 is a schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to embodiment 2. A simultaneous supply and exhaust ventilation system 102 according to embodiment 2 is provided with an auxiliary fan 201 as a leaked refrigerant discharge means in an outside air duct 21 that draws in outdoor air. In the simultaneous supply and exhaust ventilation system 102 according to embodiment 2, instead of the air path switching damper unit 7 of the simultaneous supply and exhaust ventilation system 101 according to embodiment 1, an auxiliary fan 201 is provided in the outside air duct 21 connecting the outdoors to the supply and exhaust inlet 11. By providing the auxiliary fan 201, which is a separate device, outside the simultaneous supply and exhaust ventilation system 102 according to embodiment 2, a simultaneous supply and exhaust ventilation system is formed in which the auxiliary fan 201 is controlled by the control unit 8 of the simultaneous supply and exhaust ventilation system 102. In FIG. 8, the air flow during normal operation is indicated by the arrows Fea and Fsa, and in FIG. 9, the air flow when a refrigerant leak is detected is indicated by the arrows Fea and Fsa.

[0036] In the simultaneous supply and exhaust ventilation system 101 according to the first embodiment, the air path switching damper unit 7, which serves as a leaked refrigerant discharge means, includes a first damper 71, a second damper 72, and damper drivers 74 and 75, and is configured to operate the air path switching damper unit 7 to connect the supply air path and the exhaust air path, and to discharge refrigerant leaked into the supply air path from the exhaust outlet 14 to the outdoors via the exhaust duct 24. On the other hand, in the simultaneous supply and exhaust ventilation system 102 according to the second embodiment, the auxiliary blower 201 provided in the supply air path serves as a leaked refrigerant discharge means, and is configured to operate the auxiliary blower 201 to discharge refrigerant leaked into the supply air path from the supply air inlet 11 to the outdoors via the outside air duct 21.

[0037] 8 and 9, the same or equivalent components as those of the simultaneous supply and exhaust ventilation device 101 according to the first embodiment are designated by the same reference numerals, and the description thereof will be omitted here.

[0038] The auxiliary fan 201 is provided in the supply air duct of the simultaneous supply and exhaust ventilation system 102, between the supply air inlet 11 and the first heat exchanger 4. When the auxiliary fan 201 is operated, it draws in air from the supply air duct of the simultaneous supply and exhaust ventilation system 102, blows it out through the supply air inlet 11, and generates an airflow that is exhausted to the outdoors via the external fresh air duct 21 connected to the supply air inlet. When the refrigerant detection sensor 6 detects a refrigerant concentration equal to or higher than a predetermined reference value, the control unit 8 operates the auxiliary fan 201, which serves as a leaked refrigerant discharge means. The auxiliary fan 201 may be provided in the supply air duct of the simultaneous supply and exhaust ventilation system 102, between the supply air inlet 11 and the second heat exchanger 5.

[0039] Next, the operation of the simultaneous supply and exhaust ventilation system 102 according to the second embodiment will be described. In the simultaneous supply and exhaust ventilation system 102 according to the second embodiment, during normal operation, the auxiliary fan 201, which serves as a leaked refrigerant discharge means, is not operated. Therefore, the auxiliary fan 201 installed in the supply air duct is kept stopped, while the supply air blower 3 and the exhaust air blower 2 are operated. During normal operation, air flows in the directions indicated by arrows Fea and Fsa in FIG. 8 . Arrow Fsa in the figure indicates the flow of supply air, and arrow Fea indicates the flow of exhaust air. When the refrigerant detection sensor 6 detects a refrigerant concentration equal to or greater than a predetermined reference value, the control unit 8 operates the auxiliary fan 201, which serves as a leaked refrigerant discharge means, and stops the supply air blower 3. As a result, the air duct used as the supply air duct during normal operation is converted into an air duct for discharging leaked refrigerant. Therefore, the flow of supply air indicated by arrow Fsa in FIG. 8 changes direction to that indicated by arrow Fsa in FIG. 9, and the leaked refrigerant is discharged outdoors without being supplied indoors.

[0040] Modification of Embodiment 2. Figure 10 is a schematic diagram showing the damper position when a refrigerant leak is detected in a simultaneous supply and exhaust ventilation system according to a modification of Embodiment 2. The simultaneous supply and exhaust ventilation system 102 according to a modification of Embodiment 2 includes an auxiliary fan 201 and a branching section 301 in the supply air duct as a leaked refrigerant discharge means. As with Figure 9, the direction of arrow Fsa in Figure 10 indicates the air flow when a refrigerant leak is detected.

[0041] In the second embodiment, auxiliary fan 201 is provided in the air supply duct, and therefore auxiliary fan 201 may provide resistance when air supply fan 3 is operated to draw in outdoor air during normal operation, potentially reducing the amount of air supplied. In a variation of the second embodiment, branch section 301 is provided near the outdoor end of the air supply duct, and first air passage 51 is provided, one end of which communicates with outside air port 31 in the outdoor wall surface and the other end of which communicates with branch section 301, and refrigerant discharge air passage 52 is provided, one end of which communicates with second exhaust port 35 in the outdoor wall surface and the other end of which communicates with branch section 301. Auxiliary fan 201 is provided in refrigerant discharge air passage 52.

[0042] In FIG. 10, the same or equivalent components as those of the simultaneous supply and exhaust ventilation systems 101 and 102 described in the first and second embodiments are designated by the same reference numerals, and the description thereof will be omitted here.

[0043] The side of the outer casing 1 of the simultaneous supply and exhaust ventilation device 102 is provided with an air supply inlet 11 that communicates with a first air duct 51, which is an air supply duct, and connects to an external fresh air duct 21, and a refrigerant discharge port 15 that communicates with a refrigerant discharge duct 52 and connects to an external second exhaust duct 55. One end of the external second exhaust duct 55 is connected to the refrigerant discharge port 15, and the other end communicates with a second exhaust port 35 on an outdoor wall. The branching section 301 is provided with an air duct switching shutter 302 that switches between the first air duct 51 and the refrigerant discharge duct 52. In the simultaneous supply and exhaust ventilation device 102 pertaining to the variation of the second embodiment, the leaked refrigerant discharge means is composed of an auxiliary fan 201 and an air duct switching shutter 302.

[0044] During normal operation, the leaked refrigerant discharge means is not operated, air path switching shutter 302 opens first air path 51, refrigerant discharge air path 52 is kept closed, auxiliary blower 201 is stopped, and supply air blower 3 and exhaust air blower 2 are operated. When refrigerant detection sensor 6 detects a refrigerant concentration equal to or higher than a preset reference value, control unit 8 operates the leaked refrigerant discharge means, air path switching shutter 302 closes first air path 51 and opens refrigerant discharge air path 52, operates auxiliary blower 201, and stops supply air blower 3. In other words, when the leaked refrigerant discharge means is not operating, the air path switching shutter 302 moves to a first position where outdoor air is drawn into the supply air duct from the outdoors via the outside air duct 21, and when the leaked refrigerant discharge means is operating, the shutter moves to a second position where the auxiliary blower 201 draws in refrigerant that has leaked into the supply air duct and discharges it to the outdoors from the second exhaust port 35 via the refrigerant discharge air duct 52. In Figure 10, the first position of the air path switching shutter 302 is indicated by a dotted line, and the second position is indicated by a solid line. The air path switching shutter 302 may be operated by either a wind pressure type or an electric motor.

[0045] By providing the branch section 301, in addition to the same effects as the simultaneous supply and exhaust ventilation device 102 of embodiment 2, since the auxiliary blower 201 is not in the supply air duct, the influence of the auxiliary blower 201 is not exerted when drawing in outdoor air during normal operation, and pressure loss is reduced, so the supply air volume does not decrease.

[0046] In the second embodiment, the simultaneous supply and exhaust ventilation device 102 is provided with the auxiliary fan 201, but the auxiliary fan 201 may be provided in the outside air duct 21 outside the simultaneous supply and exhaust ventilation device 102 to form a separate simultaneous supply and exhaust ventilation system. Similarly, in the modified example of the second embodiment, the simultaneous supply and exhaust ventilation device 102 is provided with the auxiliary fan 201, the branching unit 301, the air path switching shutter 302, the first air path 51, the refrigerant discharge air path 52, and the refrigerant discharge port 15 in the supply air path, but these may be provided outside the simultaneous supply and exhaust ventilation device 102 to form a simultaneous supply and exhaust ventilation system.

[0047] The configurations shown in the above embodiments are merely examples of the content, and may be combined with other known technologies, or parts of the configurations may be omitted or modified without departing from the spirit of the invention.

[0048] DESCRIPTION OF SYMBOLS 1 Outer casing, 2 Exhaust air blower, 3 Intake air blower, 4 First heat exchanger, 5 Second heat exchanger, 6 Refrigerant detection sensor, 7 Air path switching damper section, 71 First damper, 72 Second damper, 73 Interlocking belt, 74, 75 Damper drive section, 8 Control section, 9 Exhaust air path switching damper, 10 Air path communication passage, 11 Intake air inlet, 12 Intake air outlet, 13 Exhaust air inlet, 14 Exhaust air outlet, 15 Refrigerant discharge port, 21 Outside air duct, 22 Intake air duct, 23 Return air duct, 24 Exhaust duct, 31 Outside air port, 32 Intake air port, 33 Return air port, 34 Exhaust port, 35 Second exhaust port, 51 First air path, 52 Refrigerant discharge air path, 55 Second exhaust duct, 81 First slider section, 82 First plate portion, 83, second plate portion, 84, second slider portion, 85, first hinge portion, 86, second hinge portion, 87, third hinge portion, 101, 102, simultaneous supply and exhaust type ventilation device, 201, auxiliary blower, 301, branch portion, 302, air path switching shutter.

Claims

1. A casing provided with an air intake port that takes in outdoor air, an air intake port that supplies outdoor air indoors, an exhaust air intake port that draws in indoor air, an exhaust air outlet that discharges indoor air to the outside, an air intake duct connecting the air intake port and the air intake port, and an exhaust air duct connecting the exhaust air intake port and the exhaust air outlet, an air intake fan installed in the air intake duct and forming an air intake flow in the air intake duct, an exhaust fan installed in the exhaust duct and forming an exhaust flow in the exhaust duct, a first heat exchanger installed in the casing across the air intake duct and the exhaust duct and exchanging heat between the air intake flow and the exhaust flow, and a second heat exchanger installed in the air intake duct and having a refrigerant circuit that heats or cools air passing through the air intake duct, a refrigerant detection sensor installed in the supply air duct that detects refrigerant leaking from the refrigerant circuit into the supply air duct; leaked refrigerant discharge means that discharges the refrigerant leaked into the supply air duct to the outdoors; and a control unit that controls the operation of the supply air blower and the exhaust air blower, and that operates the leaked refrigerant discharge means when the refrigerant detection sensor detects a refrigerant concentration that is equal to or higher than a predetermined reference value.

2. A simultaneous supply and exhaust ventilation system as described in claim 1, comprising: an air duct communication passage that communicates the supply air duct and the exhaust air duct; and a first damper that opens and closes the air duct communication passage, wherein the leaked refrigerant discharge means is composed of the air duct communication passage and the first damper, and wherein during normal ventilation when the refrigerant detection sensor does not detect a refrigerant concentration equal to or greater than a preset reference value, the first damper is positioned to close the air duct communication passage, and during refrigerant leakage detection when the refrigerant detection sensor detects a refrigerant concentration equal to or greater than a preset reference value, the first damper is positioned to open the air duct communication passage.

3. A simultaneous supply and exhaust ventilation system as described in claim 2, characterized in that it comprises: a second damper installed in the supply air duct between the second heat exchanger and the supply air outlet and opening and closing the supply air duct; and a third damper installed in the exhaust air duct between the air duct connection passage and the exhaust air inlet and opening and closing the exhaust air duct, wherein the leaked refrigerant discharge means is composed of the air duct connection passage, the first damper, the second damper and the third damper, wherein during normal ventilation, the first damper is positioned to close the air duct connection passage, the second damper is positioned to open the supply air duct, and the third damper is positioned to open the exhaust air duct, and when refrigerant leakage is detected, the first damper is positioned to open the air duct connection passage, the second damper is positioned to close the supply air duct, and the third damper is positioned to close the exhaust air duct.

4. A simultaneous supply and exhaust ventilation system as described in claim 3, characterized in that the first damper and the second damper are integrally constructed.

5. A simultaneous supply and exhaust ventilation system as described in claim 3, characterized in that the first damper and the second damper are configured to be operated in conjunction with one driving unit.

6. An air duct communication passage is provided which communicates the intake air duct and the exhaust air duct, and the leaked refrigerant discharge means comprises a first slider portion which moves between an intermediate portion which is a portion between the intake air outlet and the exhaust air inlet and a first position which is a position directly facing the intake air outlet, a first plate portion which is rotatably connected to the first slider portion, a second slider portion which moves between the intermediate portion and a second position which is a position directly facing the exhaust air inlet, and a second plate portion which is rotatably connected to each of the first plate portion and the second slider portion, and during normal ventilation, the leaked refrigerant discharge means has each of the first slider portion and the second slider portion positioned at the intermediate portion, and the first plate portion and the second plate portion bent so as to overlap each other to close the air duct communication passage, 2. The simultaneous supply and exhaust ventilation device according to claim 1, wherein, when a refrigerant leak is detected, the leaked refrigerant discharge means positions the first slider portion at the first position and the second slider portion at the second position, and the first slider portion, the first plate portion, the second plate portion and the second slider portion spread out into flat plate shapes to block the supply air outlet and the exhaust air inlet.

7. A simultaneous supply and exhaust type ventilation system as described in claim 1, further comprising: an auxiliary fan that is provided midway along the intake air duct and forms an exhaust flow that blows the air in the intake air duct out of the intake air inlet; the auxiliary fan constitutes a leaked refrigerant discharge means; when the leaked refrigerant discharge means is not operating, the intake air blower is operated and the auxiliary fan is kept in an inoperable state; and when the leaked refrigerant discharge means is operating, the intake air blower is stopped and the auxiliary fan is operated.

8. A device comprising: a branch section provided in the air supply duct between the air supply inlet and the first heat exchanger; a refrigerant outlet provided separately from the air supply inlet; a refrigerant outlet duct having one end communicating with the refrigerant outlet and the other end communicating with the branch section; an air path switching shutter provided at the branch section for switching the air supply duct downstream of the branch section to communicate with either the air supply inlet or the refrigerant outlet; and an auxiliary fan provided midway along the refrigerant outlet duct for forming an exhaust flow that blows air in the air supply duct downstream of the branch section out of the refrigerant outlet, wherein the leaked refrigerant discharge means is composed of the air path switching shutter and the auxiliary fan, and when the leaked refrigerant discharge means is not operating, the air supply fan operates and the auxiliary fan is kept in an inoperable state, and the air path switching shutter communicates with the air supply inlet, 2. The simultaneous supply and exhaust ventilation system according to claim 1, wherein, when the leaked refrigerant exhaust means is operating, the supply air blower is stopped, the auxiliary blower is operated, and the air path switching shutter opens the refrigerant exhaust port.

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