JP5109590B2 - Humidity control device - Google Patents

Description

  The present invention passes through the adsorption heat exchanger while switching the operating state of the two adsorption heat exchangers as an evaporator and a condenser by alternately switching the refrigerant circulation direction by means of a four-way switching valve. The present invention relates to a humidity control apparatus that adjusts the humidity of air to be supplied and supplies the air indoors.

  2. Description of the Related Art Conventionally, a humidity control apparatus that supplies dehumidified or humidified air to a room is known (for example, see Patent Document 1). The humidity control apparatus of this patent document is configured to adjust the humidity of air by performing an adsorption operation for adsorbing moisture in the air to the adsorbent and a regeneration operation for desorbing moisture from the adsorbent.

Such a humidity control apparatus includes a refrigerant circuit in which a compressor, an expander, two adsorption heat exchangers, and a four-way switching valve are connected. One of the adsorption heat exchangers functions as an evaporator for adsorption. While the operation is performed, the other adsorption heat exchanger is caused to function as a condenser to perform the regeneration operation. Then, the humidity control apparatus switches the refrigerant circulation direction by a four-way switching valve, thereby switching between the adsorption operation and the regeneration operation of the two adsorption heat exchangers, thereby performing adsorption heat exchange in which moisture is adsorbed in the operation before switching. While the regenerator performs the regeneration operation, the adsorption operation is performed by the adsorption heat exchanger from which moisture has been desorbed in the operation before switching. Thus, the humidity control apparatus is configured to perform semi-permanent dehumidification and humidification on the air by alternately switching between the adsorption operation and the regeneration operation of the two adsorption heat exchangers.
JP 2006-349304 A

  However, in the configuration in which the four-way switching valve is frequently switched as in the humidity control device described above, the valve body of the four-way switching valve is worn and the deterioration of the four-way switching valve is accelerated. When the four-way switching valve deteriorates, refrigerant leaks between the ports to be blocked.

  Normally, refrigerants with different temperatures and pressures flow between one set of ports and the other set of ports communicated by the four-way switching valve. It leaks to the side, and the humidity control device cannot exhibit the desired performance.

  Therefore, in the humidity control apparatus, the durability required for the four-way switching valve is increased as compared with the air conditioner, and the necessity for detecting the leakage of the four-way switching valve is increased.

  This invention is made | formed in view of this point, The place made into the objective is to determine easily the leakage state of a four-way switching valve in a humidity control apparatus.

The first invention includes two adsorption heat exchangers (51, 52) in which at least one performs an adsorption operation for adsorbing moisture and the other performs a regeneration operation for desorption of moisture, and a four-way switching valve for switching the refrigerant circulation direction (55) is connected to the refrigerant circuit (50) and a control unit (110) for controlling the four-way switching valve (55), and the control unit (110) circulates the refrigerant by the four-way switching valve (55). By switching the direction alternately, the humidity of the air passing through the adsorption heat exchanger (51, 52) is adjusted to the room while switching the adsorption operation and the regeneration operation of the two adsorption heat exchangers (51, 52). The humidity control device to be supplied is the target. For the refrigerant passing through the four-way switching valve (55), the temperature of the refrigerant before passing through the four-way switching valve (55) and the temperature of the refrigerant after passing through the four-way switching valve (55) are detected. Leakage of the four-way switching valve (55) based on the temperature of the refrigerant before and after passing through the four-way switching valve (55) detected by the temperature detection means (94,95) and the temperature detection means (94,95) And a leak determination means (120) for determining the state , wherein the temperature detection means (94, 95) connects the four-way switching valve (55) and one of the adsorption heat exchangers (51). Refrigerant flowing through the suction side connecting pipe (57) connecting the upstream side temperature detecting means (95) for detecting the temperature of the refrigerant flowing through the connecting pipe (58) and the four-way switching valve (55) and the suction side of the compressor. And a downstream temperature detecting means (94) for detecting the temperature of the control unit (1). 10) when the four-way switching valve (55) is controlled to connect the suction side connecting pipe (57) and the heat exchanger connecting pipe (58), the downstream side temperature detecting means (94 ) And the detection result of the upstream temperature detection means (95), the leakage state of the four-way switching valve (55) is determined .

  In the case of the above configuration, the temperature of the refrigerant before and after passing through the four-way switching valve (55) is obtained by the temperature detecting means (94, 95).

  Here, when the four-way switching valve (55) is normal, the temperature of the refrigerant hardly changes before and after passing through the four-way switching valve (55). However, when wear occurs in the four-way switching valve (55) and leakage occurs inside, the refrigerants that are blocked from each other inside the four-way switching valve (55) and flow between different ports are mixed with each other. Therefore, the temperature of the refrigerant greatly changes before and after passing through the four-way selector valve (55).

Therefore, the leakage determination means (120) monitors the refrigerant temperature before and after passing through the four-way switching valve (55) obtained from the detection result of the temperature detection means (94, 95), thereby providing a four-way switching valve (55). ) Leakage state can be easily determined .

For pre Symbol configuration, among the piping that connects the four-way selector valve (55) and two of the adsorption heat exchangers and (51, 52), respectively, one of the pipes (i.e., the heat exchanger connection pipe (58) Only) is provided with upstream temperature detecting means (95). The leakage determination means (120) is configured such that when the heat exchanger connection pipe (58) and the suction side connection pipe (57) connected to the suction side of the compressor are connected by a four-way switching valve (55). That is, when it is assumed that low-pressure refrigerant is flowing from the heat exchanger connecting pipe (58) to the suction side connecting pipe (57) via the four-way switching valve (55), the heat exchanger connecting pipe (58 ) And the suction side connecting pipe (57) are compared to determine the leakage state of the four-way switching valve (55). In other words, when a leak occurs in the four-way selector valve (55), the high-pressure refrigerant leaks to the low-pressure side, so the low-pressure refrigerant is assumed to flow through the four-way selector valve (55). The leakage state of the four-way switching valve (55) can be easily determined by comparing the temperatures of the refrigerants.

  Further, the upstream side temperature detecting means (58) is connected only to the heat exchanger connecting pipe (58) that connects one of the adsorption heat exchangers (51, 52) to the four-way switching valve (55). 95), and when the pipe provided with the upstream temperature detecting means (95) and the pipe provided with the downstream temperature detecting means (94) are connected by a four-way selector valve (55) Even in the configuration that performs the operation, the humidity control device is operated while the four-way switching valve (55) is frequently switched. Can be reliably determined, and the number of parts such as temperature detecting means can be reduced.

According to a second invention, in the first or second invention, the leakage determination means (120) includes a refrigerant before passing through the four-way switching valve (55) and a refrigerant after passing through the four-way switching valve (55). It is determined that the four-way switching valve (55) is out of order when the temperature difference between the two becomes larger than a predetermined value.

  In the case of the above configuration, when the refrigerant temperature difference before and after passing through the four-way switching valve (55) is equal to or less than a predetermined value, the leakage determination means (120) indicates that the four-way switching valve (55) has failed. Do not judge. In this way, even if there is a detection error of the temperature detection means or an acceptable amount of leakage of the refrigerant, it will be a failure until the temperature difference of the refrigerant before and after passing through the four-way switching valve (55) becomes larger than a predetermined value. It can be tolerated without judging. As a result, it is possible to prevent erroneous determination that the four-way switching valve (55) is out of order even though the refrigerant temperature difference before and after passing through the four-way switching valve (55) is within an allowable range. .

  According to the present invention, the temperature detection means (94, 95) for detecting the temperature of the refrigerant before and after passing through the four-way switching valve (55) is provided, and the temperature detection means (94) is provided by the leak determination means (120). 95), the leakage state of the four-way switching valve (55) can be easily determined by monitoring the refrigerant temperature before and after passing through the four-way switching valve (55).

Further , when the four-way switching valve (55) is controlled so as to connect the suction side connecting pipe (57) and the heat exchanger connecting pipe (58), the detection by the downstream side temperature detecting means (94) is performed. By determining the leakage state of the four-way switching valve (55) based on the result and the detection result of the upstream temperature detection means (95), the four-way switching valve (55) and the two adsorption heat exchangers (51 , 52), the upstream side temperature detecting means (95) is provided only in one of the pipes connecting the pipes, that is, the heat exchanger connecting pipe (58). A leak condition can be determined. Here, the heat exchanger connecting pipe (58) provided with the upstream temperature detecting means (95) is not a pipe connected to the discharge side of the compressor by the four-way switching valve (55), but a suction side connecting pipe ( The leakage of the four-way switching valve (55) can be reliably determined by determining the leakage state when it is assumed that it is connected to 57).

  As described above, when the four-way switching valve (55) is controlled to connect the suction side connecting pipe (57) and the heat exchanger connecting pipe (58), the leakage state of the four-way switching valve (55) is determined. Even in such a configuration, the humidity control apparatus operates while switching the adsorption operation and the regeneration operation of the two adsorption heat exchangers (51, 52), that is, frequently switching the state of the four-way switching valve (55). Therefore, the opportunity to determine the leakage state frequently arrives, and the leakage of the four-way switching valve (55) can be reliably determined.

  Furthermore, the upstream side temperature detection means (95) is provided not only in both of the pipes connecting the four-way switching valve (55) and the two adsorption heat exchangers (51, 52), but only in one pipe. The number of parts can be reduced.

According to the second invention, the leak determination means (120) is configured such that the temperature difference between the refrigerant before passing through the four-way switching valve (55) and the refrigerant after passing through the four-way switching valve (55) is larger than a predetermined value. By determining that the four-way switching valve (55) is out of order, it is possible to prevent erroneous determination that the four-way switching valve (55) has failed due to a detection error of the temperature detection means. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The humidity control device (10) of the present embodiment performs indoor ventilation as well as indoor humidity adjustment. At the same time, the taken outdoor air (OA) is humidity-adjusted and supplied to the room. ) To the outside.

<Overall configuration of humidity control device>
The humidity control apparatus (10) will be described with reference to FIGS. Note that “upper”, “lower”, “left”, “right”, “front”, “rear”, “front”, and “rear” used in the description here are the humidity control device (10) from the front side unless otherwise stated. It means the direction when viewed.

  The humidity control device (10) includes a casing (11). A refrigerant circuit (50) is accommodated in the casing (11). Connected to the refrigerant circuit (50) are a first adsorption heat exchanger (51), a second adsorption heat exchanger (52), a compressor (53), an electric expansion valve (54), and a four-way switching valve (55). Has been. Details of the refrigerant circuit (50) will be described later.

  The casing (11) is formed in a rectangular parallelepiped shape that is slightly flat and relatively low in height. In the casing (11) shown in FIG. 1, the left front side (ie, front) is the front panel (12), and the right back side (ie, back) is the back panel (13). Is the first side panel (14), and the left back side is the second side panel (15).

  The casing (11) is formed with an outside air suction port (24), an inside air suction port (23), an air supply port (22), and an exhaust port (21). The outside air inlet (24) and the inside air inlet (23) are open to the back panel (13). The outside air inlet (24) is disposed in the lower part of the back panel (13). The inside air suction port (23) is arranged in the upper part of the back panel (13). The air supply port (22) is disposed near the end of the first side panel (14) on the front panel (12) side. The exhaust port (21) is disposed near the end of the second side panel (15) on the front panel (12) side.

  The internal space of the casing (11) includes an upstream divider plate (71), a downstream divider plate (72), a central divider plate (73), a first divider plate (74), and a second divider plate ( 75). These partition plates (71 to 75) are all erected on the bottom plate of the casing (11), and divide the internal space of the casing (11) from the bottom plate of the casing (11) to the top plate. .

  The upstream divider plate (71) and the downstream divider plate (72) are parallel to the front panel portion (12) and the rear panel portion (13), and are spaced at a predetermined interval in the longitudinal direction of the casing (11). Has been placed. The upstream divider plate (71) is disposed closer to the rear panel portion (13). The downstream partition plate (72) is disposed closer to the front panel portion (12).

  The first partition plate (74) and the second partition plate (75) are installed in a posture parallel to the first side panel portion (14) and the second side panel portion (15). The first partition plate (74) is spaced a predetermined distance from the first side panel (14) so as to close the space between the upstream partition plate (71) and the downstream partition plate (72) from the right side. Has been placed. The second partition plate (75) is spaced from the second side panel (15) by a predetermined distance so as to close the space between the upstream partition plate (71) and the downstream partition plate (72) from the left side. Has been placed.

  The central partition plate (73) is disposed between the upstream partition plate (71) and the downstream partition plate (72) in a posture orthogonal to the upstream partition plate (71) and the downstream partition plate (72). Yes. The central partition plate (73) is provided from the upstream partition plate (71) to the downstream partition plate (72), and the space between the upstream partition plate (71) and the downstream partition plate (72) is left and right. It is divided into.

  In the casing (11), the space between the upstream partition plate (71) and the back panel (13) is divided into two upper and lower spaces, and the upper space forms the inside air passage (32). The lower space constitutes the outside air passage (34). The room air side passage (32) communicates with the room through a duct connected to the room air inlet (23). An inside air filter (27) and an inside air humidity sensor (96) are installed in the inside air passage (32). The outside air passage (34) communicates with the outdoor space via a duct connected to the outside air inlet (24). An outside air filter (28) and an outside air humidity sensor (97) are installed in the outside air passage (34).

  The space between the upstream divider plate (71) and the downstream divider plate (72) in the casing (11) is divided into left and right by the central divider plate (73), and is located on the right side of the central divider plate (73). The space constitutes the first heat exchanger chamber (37), and the space on the left side of the central partition plate (73) constitutes the second heat exchanger chamber (38). A first adsorption heat exchanger (51) is accommodated in the first heat exchanger chamber (37). The second adsorption heat exchanger (52) is accommodated in the second heat exchanger chamber (38). Moreover, although not shown in figure, the electric expansion valve (54) of a refrigerant circuit (50) is accommodated in the 1st heat exchanger chamber (37).

  Each adsorption heat exchanger (51, 52) has an adsorbent supported on the surface of a so-called cross fin type fin-and-tube heat exchanger, and is a rectangular thick plate or flat rectangular parallelepiped as a whole. It is formed in a shape. Each adsorption heat exchanger (51, 52) is placed in the heat exchanger chamber (37, 38) with its front and back surfaces parallel to the upstream partition plate (71) and downstream partition plate (72). It is erected.

  In the internal space of the casing (11), the space along the front surface of the downstream partition plate (72) is partitioned vertically, and the upper portion of the vertically partitioned space is the air supply side passage ( 31), and the lower part constitutes the exhaust side passage (33).

  The upstream partition plate (71) is provided with four open / close dampers (41 to 44). Each damper (41-44) is formed in the shape of a substantially horizontally long rectangle. Specifically, in a part (upper part) facing the room air passage (32) in the upstream partition (71), the first room air damper (41) is attached to the right side of the central partition (73). The second inside air damper (42) is attached to the left side of the central partition plate (73). Moreover, in the part (lower part) which faces an external air side channel | path (34) among upstream side partition plates (71), the 1st external air side damper (43) is attached to the right side rather than a center partition plate (73), A second outside air damper (44) is attached to the left side of the central partition plate (73).

  The downstream partition plate (72) is provided with four open / close dampers (45 to 48). Each damper (45-48) is formed in the shape of a substantially horizontally long rectangle. Specifically, in the part (upper part) facing the supply side passageway (31) in the downstream partition plate (72), the first supply side damper (45) is located on the right side of the central partition plate (73). The second air supply side damper (46) is attached to the left side of the central partition plate (73). Moreover, in the part (lower part) which faces an exhaust side channel | path (33) among downstream partition plates (72), the 1st exhaust side damper (47) is attached to the right side rather than a center partition plate (73), A second exhaust side damper (48) is attached to the left side of the central partition plate (73).

  In the casing (11), the space between the air supply side passage (31) and the exhaust side passage (33) and the front panel portion (12) is divided into left and right by the partition plate (77). The space on the right side of (77) constitutes the air supply fan chamber (36), and the space on the left side of the partition plate (77) constitutes the exhaust fan chamber (35).

  The air supply fan (26) is accommodated in the air supply fan chamber (36). The exhaust fan chamber (35) accommodates an exhaust fan (25). The supply fan (26) and the exhaust fan (25) are both centrifugal multiblade fans (so-called sirocco fans). The air supply fan (26) blows out the air sucked from the downstream side partition plate (72) side to the air supply port (22). The exhaust fan (25) blows out the air sucked from the downstream partition plate (72) side to the exhaust port (21).

  The supply fan chamber (36) accommodates a compressor (53) and a four-way switching valve (55) of the refrigerant circuit (50). The compressor (53) and the four-way selector valve (55) are disposed between the air supply fan (26) and the partition plate (77) in the air supply fan chamber (36).

  In the casing (11), the space between the first partition (74) and the first side panel (14) forms a first bypass passage (81). The starting end of the first bypass passage (81) communicates only with the outside air passage (34) and is blocked from the inside air passage (32). The terminal end of the first bypass passage (81) is partitioned by the partition plate (78) from the air supply side passage (31), the exhaust side passage (33), and the air supply fan chamber (36). A first bypass damper (83) is provided in a portion of the partition plate (78) facing the supply fan chamber (36).

  In the casing (11), the space between the second partition (75) and the second side panel (15) constitutes a second bypass passage (82). The starting end of the second bypass passage (82) communicates only with the inside air passage (32) and is blocked from the outside air passage (34). The terminal end of the second bypass passage (82) is partitioned by the partition plate (79) from the air supply side passage (31), the exhaust side passage (33), and the exhaust fan chamber (35). A second bypass damper (84) is provided in a portion of the partition plate (79) facing the exhaust fan chamber (35).

  In the right side view and the left side view of FIG. 2, the first bypass passage (81), the second bypass passage (82), the first bypass damper (83), and the second bypass damper (84) are shown. Is omitted.

<Configuration of refrigerant circuit>
As shown in FIG. 3, the refrigerant circuit (50) includes a first adsorption heat exchanger (51), a second adsorption heat exchanger (52), a compressor (53), an electric expansion valve (54), and a four-way switching valve. (55) is a closed circuit. The refrigerant circuit (50) performs a vapor compression refrigeration cycle by circulating the filled refrigerant.

  In the refrigerant circuit (50), the compressor (53) has a discharge side connected to the first port (P1) of the four-way switching valve (55) via the discharge side connection pipe (56), and a suction side connected to the suction side connection pipe ( 57) and connected to the second port (P2) of the four-way selector valve (55). In the refrigerant circuit (50), the third port (P3) of the four-way switching valve (55) and one end of the first adsorption heat exchanger (51) are connected via the first connection pipe (58), The fourth port (P4) of the switching valve (55) and one end of the second adsorption heat exchanger (52) are connected via the second connecting pipe (59). Furthermore, in the refrigerant circuit (50), the other end of the first adsorption heat exchanger (51) and the other end of the second adsorption heat exchanger (52) are connected via the third connection pipe (60), An electric expansion valve (54) is interposed in the third connection pipe (60). This 1st connection piping (58) comprises a heat exchanger connection piping.

  The four-way selector valve (55) is in a first state (FIG. 3A) in which the first port (P1) and the third port (P3) communicate with each other and the second port (P2) and the fourth port (P4) communicate with each other. And the second state (shown in FIG. 3B) in which the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other. (Status).

  More specifically, as shown in FIG. 4, the four-way selector valve (55) includes a cylindrical main body (551) whose both ends are closed by plugs (552, 553). A short pipe which is the above-described four ports (P1 to P4) is provided on a side portion of the main body (551). Specifically, a first port (P1) is provided extending in the radial direction of the main body (551) at the longitudinal center of the main body (551). And the 2nd-4th port (P2-P4) is each provided in the diameter direction of the main body (551) on the opposite side to the 1st port (P1) across the longitudinal direction axis of the main body (551). Yes. These second to fourth ports (P2 to P4) are arranged in the longitudinal direction (from left to right in FIG. 4) in the order of the third, second and fourth ports (P3, P2, P4).

  Housed in the main body (551) are a bowl-shaped valve body (558) and pistons (555,556) integrally attached to both sides of the valve body (558) by connecting plates (557). . Inside the main body (551) is provided a valve seat (554) on which a valve body (558) is seated at a portion corresponding to the opening of the third, second and fourth ports (P3, P2, P4). Yes.

  The interior of the main body (551) and plug (552,553) is divided into three chambers, a high pressure chamber (R1), a first working chamber (R2), and a second working chamber (R3) by both pistons (555,556). Yes.

  The four-way switching valve (55) includes a pilot valve (559). The pilot valve (559) includes a first conduit (561) communicating with the first working chamber (R2), a second conduit (562) communicating with the second working chamber (R3), and a first port (P1). A third conduit (563) communicating with the second port (P2) and a fourth conduit (564) communicating with the second port (P2) are connected. The pilot valve (559) is in a first state in which the first conduit (561) and the third conduit (563) communicate with each other and the second conduit (562) and the fourth conduit (564) communicate with each other (FIG. 5 ( A state) and a second state (FIG. 5B) in which the first conduit (561) and the fourth conduit (564) communicate with each other and the second conduit (562) and the third conduit (563) communicate with each other. (State).

  Specifically, the pilot valve (559) switches to the first state when energization is stopped (OFF). Then, in the four-way switching valve (55), the first working chamber (R2) is filled with high-pressure gas refrigerant from the first port (P1), and the second working chamber (R3) is low-pressure from the second port (P2). Filled with gas refrigerant. That is, when the pilot valve (559) is switched to the first state, the piston (555,556) is pushed to the right in FIG. 4 due to the pressure difference between the two working chambers (R2, R3) (the state indicated by the two-dot chain line in FIG. 4). ), The valve body (558) is in the first state (the state shown in FIG. 3A) in which the second port (P2) and the fourth port (P4) communicate with each other.

  On the other hand, the pilot valve (559) switches to the second state when energized (ON). Then, in the four-way switching valve (55), the first working chamber (R2) is filled with the low pressure gas refrigerant from the second port (P2), and the second working chamber (R3) is filled with the high pressure from the first port (P1). Filled with gas refrigerant. That is, when the pilot valve (559) is switched to the second state, the piston (555, 556) is pushed to the left in FIG. 4 due to the pressure difference between the two working chambers (R2, R3) (state shown by the solid line in FIG. 4). Then, the valve body (558) enters the second state (the state shown in FIG. 3B) in which the third port (P3) and the second port (P2) communicate with each other.

  In the refrigerant circuit (50), a discharge side connection pipe (56) connecting the discharge side of the compressor (53) and the first port (P1) of the four-way switching valve (55) includes a high pressure sensor (91), A discharge pipe temperature sensor (93) is attached. The high pressure sensor (91) measures the pressure of the refrigerant discharged from the compressor (53). The discharge pipe temperature sensor (93) measures the temperature of the refrigerant discharged from the compressor (53).

  In the refrigerant circuit (50), a suction side connecting pipe (57) connecting the suction side of the compressor (53) and the second port of the four-way switching valve (55) includes a low pressure sensor (92), A suction pipe temperature sensor (94) is attached. The low pressure sensor (92) measures the pressure of the refrigerant sucked into the compressor (53). The suction pipe temperature sensor (94) measures the temperature of the refrigerant sucked into the compressor (53). This suction pipe temperature sensor (94) constitutes a downstream temperature detecting means.

  In the refrigerant circuit (50), a pipe temperature sensor (95) is connected to the first connection pipe (58) connecting the third port (P3) of the four-way switching valve (55) and the first adsorption heat exchanger (51). ) Is attached. The pipe temperature sensor (95) is disposed in the vicinity of the four-way switching valve (55) in this pipe and measures the temperature of the refrigerant flowing in the pipe. This pipe temperature sensor (95) constitutes upstream temperature detecting means.

<Control device configuration>
The humidity control apparatus (10) includes a controller (100). The controller (100) includes an operation control unit (110) that controls the operation of the humidity control device (10), and a leak determination unit (120) that performs leak determination control of the four-way switching valve (55). .

  The operation control unit (110) sets a set value (selection of dehumidification ventilation operation, humidification ventilation operation and simple ventilation operation, setting target humidity, etc.) input from the user, a detection result of the inside air humidity sensor (96), and the outside air Based on the detection result of the humidity sensor (97), the operation control of the compressor (53) in the refrigerant circuit (50), the opening control of the electric expansion valve (54), the switching control of the four-way switching valve (55), Open / close control of dampers (41-48, 83, 84). This operation control part (110) comprises a control part.

  The leakage determination unit (120) determines a failure due to leakage of the four-way switching valve (55) based on the detection result of the high pressure sensor (91) and the detection result of the pipe temperature sensor (95). This leak determination unit (120) constitutes a leak determination means.

  Hereinafter, detailed control contents of the operation control unit (110) and the leakage determination unit (120) will be described.

-Driving action-
In the humidity control apparatus (10) of the present embodiment, the operation control unit (110) of the controller (100) controls the electric expansion valve (54), the four-way switching valve (55), and the dampers (41 to 48, 83, 84). Thus, the dehumidification ventilation operation, the humidification ventilation operation, and the simple ventilation operation are selectively performed. The humidity control device (10) during dehumidification ventilation operation or humidification ventilation operation adjusts the humidity of the taken outdoor air (OA) and supplies it to the room as supply air (SA). To the outside as exhaust air (EA). On the other hand, the humidity control device (10) during the simple ventilation operation supplies the taken outdoor air (OA) to the room as supplied air (SA) as it is, and at the same time discharges the taken indoor air (RA) as it is. To be discharged outside the room.

<Dehumidification ventilation operation>
In the humidity control apparatus (10) during the dehumidifying ventilation operation, a first operation and a second operation described later are alternately repeated at a predetermined time interval (for example, every 3 minutes). During the dehumidifying ventilation operation, the first bypass damper (83) and the second bypass damper (84) are always closed.

  In the humidity control apparatus (10) during the dehumidification / ventilation operation, outdoor air is taken as first air from the outside air inlet (24) into the casing (11), and indoor air is taken from the inside air inlet (23) to the casing (11). It is taken in as second air.

  First, the first operation of the dehumidifying ventilation operation will be described. As shown in FIG. 4, during the first operation, the first inside air damper (41), the second outside air side damper (44), the second air supply side damper (46), and the first exhaust side damper ( 47) is opened, and the second inside air damper (42), the first outside air damper (43), the first air supply side damper (45), and the second exhaust side damper (48) are closed. In the refrigerant circuit (50) during the first operation, the four-way switching valve (55) is set to the first state (the state shown in FIG. 3A), and the first adsorption heat exchanger (51) is condensed. The second adsorption heat exchanger (52) becomes an evaporator.

  The first air that has flowed from the outside air suction port (24) into the outside air passage (34) and passed through the outside air filter (28) passes through the second outside air damper (44) and passes through the second heat exchanger chamber (38). ) And then passes through the second adsorption heat exchanger (52). In the second adsorption heat exchanger (52), moisture in the first air is adsorbed by the adsorbent, and the heat of adsorption generated at that time is absorbed by the refrigerant. The first air dehumidified by the second adsorption heat exchanger (52) flows into the supply air passage (31) through the second supply air damper (46) and passes through the supply air fan chamber (36). Later, the air is supplied into the room through the air supply port (22).

  On the other hand, the second air that has flowed into the inside air passage (32) from the inside air suction port (23) and passed through the inside air filter (27) passes through the first inside air damper (41) to form the first heat exchanger chamber. (37) and then passes through the first adsorption heat exchanger (51). In the first adsorption heat exchanger (51), moisture is desorbed from the adsorbent heated by the refrigerant, and the desorbed moisture is given to the second air. The second air given moisture in the first adsorption heat exchanger (51) flows into the exhaust side passage (33) through the first exhaust side damper (47) and passes through the exhaust fan chamber (35). It is discharged outside through the exhaust port (21).

  Next, the second operation of the dehumidifying ventilation operation will be described. As shown in FIG. 5, during this second operation, the second inside air side damper (42), the first outside air side damper (43), the first air supply side damper (45), and the second exhaust side damper ( 48) is opened, and the first inside air damper (41), second outside air damper (44), second air supply damper (46), and first exhaust damper (47) are closed. In the refrigerant circuit (50) during the second operation, the four-way switching valve (55) is set to the second state (the state shown in FIG. 3B), and the first adsorption heat exchanger (51) is evaporated. The second adsorption heat exchanger (52) becomes a condenser.

  The first air that has flowed into the outside air passage (34) from the outside air inlet (24) and passed through the outside air filter (28) passes through the first outside air damper (43) and passes through the first heat exchanger chamber (37). ) And then passes through the first adsorption heat exchanger (51). In the first adsorption heat exchanger (51), moisture in the first air is adsorbed by the adsorbent, and the adsorption heat generated at that time is absorbed by the refrigerant. The first air dehumidified by the first adsorption heat exchanger (51) flows into the supply air passage (31) through the first supply air damper (45) and passes through the supply air fan chamber (36). Later, the air is supplied into the room through the air supply port (22).

  On the other hand, the second air that has flowed from the inside air suction port (23) into the inside air side passage (32) and passed through the inside air side filter (27) passes through the second inside air side damper (42) and is thus in the second heat exchanger chamber. (38) and then passes through the second adsorption heat exchanger (52). In the second adsorption heat exchanger (52), moisture is desorbed from the adsorbent heated by the refrigerant, and the desorbed moisture is given to the second air. The second air given moisture in the second adsorption heat exchanger (52) flows into the exhaust side passage (33) through the second exhaust side damper (48) and passes through the exhaust fan chamber (35). It is discharged outside through the exhaust port (21).

<Humidified ventilation operation>
In the humidity control apparatus (10) during the humidification ventilation operation, a first operation and a second operation described later are alternately repeated at a predetermined time interval (for example, every 3 minutes). During the humidification ventilation operation, the first bypass damper (83) and the second bypass damper (84) are always closed.

  In the humidity control apparatus (10) during the humidification ventilation operation, outdoor air is taken as second air from the outside air inlet (24) into the casing (11), and indoor air is taken from the inside air inlet (23) to the casing (11). It is taken in as 1st air in.

  First, the 1st operation | movement of humidification ventilation operation is demonstrated. As shown in FIG. 6, during the first operation, the second inside air side damper (42), the first outside air side damper (43), the first air supply side damper (45), and the second exhaust side damper ( 48) is opened, and the first inside air damper (41), second outside air damper (44), second air supply damper (46), and first exhaust damper (47) are closed. In the refrigerant circuit (50) during the first operation, the four-way switching valve (55) is set to the first state (the state shown in FIG. 3A), and the first adsorption heat exchanger (51) is condensed. The second adsorption heat exchanger (52) becomes an evaporator.

  The first air that has flowed from the inside air suction port (23) into the inside air side passage (32) and passed through the inside air filter (27) passes through the second inside air side damper (42) and passes through the second heat exchanger chamber (38 ) And then passes through the second adsorption heat exchanger (52). In the second adsorption heat exchanger (52), moisture in the first air is adsorbed by the adsorbent, and the heat of adsorption generated at that time is absorbed by the refrigerant. The first air deprived of moisture in the second adsorption heat exchanger (52) flows into the exhaust side passage (33) through the second exhaust side damper (48) and passes through the exhaust fan chamber (35). It is discharged outside through the exhaust port (21).

  On the other hand, the second air that has flowed into the outside air passage (34) from the outside air inlet (24) and passed through the outside air filter (28) passes through the first outside air damper (43) and enters the first heat exchanger chamber. (37) and then passes through the first adsorption heat exchanger (51). In the first adsorption heat exchanger (51), moisture is desorbed from the adsorbent heated by the refrigerant, and the desorbed moisture is given to the second air. The second air humidified by the first adsorption heat exchanger (51) flows through the first air supply damper (45) into the air supply passage (31) and passes through the air supply fan chamber (36). Later, the air is supplied into the room through the air supply port (22).

  Next, the second operation of the humidification ventilation operation will be described. As shown in FIG. 7, during the second operation, the first inside air damper (41), the second outside air damper (44), the second air supply damper (46), and the first exhaust damper ( 47) is opened, and the second inside air damper (42), the first outside air damper (43), the first air supply side damper (45), and the second exhaust side damper (48) are closed. In the refrigerant circuit (50) during the second operation, the four-way switching valve (55) is set to the second state (the state shown in FIG. 3B), and the first adsorption heat exchanger (51) is evaporated. The second adsorption heat exchanger (52) becomes a condenser.

  The first air that has flowed from the inside air suction port (23) into the inside air passage (32) and passed through the inside air filter (27) passes through the first inside air damper (41) and passes through the first heat exchanger chamber (37 ) And then passes through the first adsorption heat exchanger (51). In the first adsorption heat exchanger (51), moisture in the first air is adsorbed by the adsorbent, and the adsorption heat generated at that time is absorbed by the refrigerant. The first air deprived of moisture by the first adsorption heat exchanger (51) flows into the exhaust side passage (33) through the first exhaust side damper (47) and passes through the exhaust fan chamber (35). It is discharged outside through the exhaust port (21).

  On the other hand, the second air that has flowed into the outside air passage (34) from the outside air inlet (24) and passed through the outside air filter (28) passes through the second outside air damper (44) to form the second heat exchanger chamber. (38) and then passes through the second adsorption heat exchanger (52). In the second adsorption heat exchanger (52), moisture is desorbed from the adsorbent heated by the refrigerant, and the desorbed moisture is given to the second air. The second air humidified by the second adsorption heat exchanger (52) flows through the second supply air damper (46) into the supply air passage (31) and passes through the supply air fan chamber (36). Later, the air is supplied into the room through the air supply port (22).

<Simple ventilation operation>
The operation of the humidity control apparatus (10) during the simple ventilation operation will be described with reference to FIG.

  In the humidity control apparatus (10) during the simple ventilation operation, the first bypass damper (83) and the second bypass damper (84) are opened, and the first room air damper (41) and the second room air damper ( 42), a first external air damper (43), a second external air damper (44), a first air supply damper (45), a second air supply damper (46), a first exhaust air damper (47), And the 2nd exhaust side damper (48) will be in a closed state. Further, during the simple ventilation operation, the compressor (53) of the refrigerant circuit (50) is stopped.

  In the humidity control apparatus (10) during the simple ventilation operation, outdoor air is taken into the casing (11) from the outside air inlet (24). The outdoor air that has flowed into the outside air passage (34) through the outside air inlet (24) flows from the first bypass passage (81) through the first bypass damper (83) into the supply fan chamber (36). Then, the air is supplied into the room through the air supply port (22).

  Further, in the humidity control apparatus (10) during the simple ventilation operation, room air is taken into the casing (11) from the inside air suction port (23). The room air that has flowed into the inside air passage (32) through the inside air inlet (23) flows from the second bypass passage (82) through the second bypass damper (84) into the exhaust fan chamber (35). Then, it is discharged to the outside through the exhaust port (21).

<Failure judgment>
In this way, while the operation control unit (110) of the controller (100) selectively performs any one of the dehumidification ventilation operation, the humidification ventilation operation, and the simple ventilation operation, the leak determination unit (120) includes the four-way switching valve (55 ) Failure is judged.

  Specifically, the leakage determination unit (120) determines the leakage state of the four-way switching valve (55) according to the flowchart shown in FIG.

  First, the leakage determination unit (120) determines whether or not the compressor (53) is in operation in step S1. When the compressor (53) is in operation, the process proceeds to step S2. On the other hand, when the compressor (53) is stopped, step S1 is repeated via step S7. Here, when the timer described later is started, the timer is stopped and reset in step S7.

  In step S2, the leakage determination unit (120) determines whether or not the four-way switching valve (55) is in the second state, that is, whether or not the pilot valve (559) is energized (ON). When the four-way switching valve (55) is in the second state, the first connecting pipe (58) and the suction side connecting pipe (57) are connected via the four-way switching valve (55). When the pilot valve (559) is energized, the process proceeds to step S3, while when the pilot valve (559) is deenergized (OFF), the process returns to step S1 via step S7. Here, when a timer to be described later is started, the timer is stopped and reset in step S7 when returning to step S1.

  In step S3, the leak determination unit (120) is detected by the refrigerant temperature Ts sucked into the compressor (53), which is detected by the suction pipe temperature sensor (94), and the pipe temperature sensor (95). The difference between the temperature T4e of the refrigerant flowing through the first connection pipe (58) connecting the third port (P3) of the four-way switching valve (55) and the first adsorption heat exchanger (51) is a predetermined temperature Tr (for example, It is judged whether it is larger than 10 ° C. When the temperature difference is larger than the predetermined temperature Tr, the process proceeds to step S4. When the temperature difference is equal to or less than the predetermined temperature Tr, the process returns to step S1 via step S7. Here, when a timer to be described later is started, the timer is stopped and reset in step S7 when returning to step S1.

  In step S4, the leak determination unit (120) starts a timer and proceeds to step S5. When the timer has already been started, the time measurement by the timer is continued.

  In step S5, the leakage determination unit (120) determines whether or not a predetermined time (for example, 2 minutes) has elapsed since the timer was started. When the predetermined time has elapsed, it is determined that the four-way selector valve (55) has a large leak and has failed, and the process proceeds to step S6. On the other hand, when the predetermined time has not elapsed, the process returns to step S1. When returning from step S5 to step S1, the timer is not stopped and reset, and the time measurement by the timer is continued.

  In step S6, the leak determination unit (120) sets a failure flag and turns on notification means (not shown) such as an LED to notify the user of the failure of the four-way switching valve (55).

  After the failure flag is set in step S6 by the leak determination unit (120), the failure flag is set, that is, the notification means is turned on, unless a predetermined release operation is performed by the user using the remote controller or the like. Is maintained.

  That is, the leak determination unit (120) is (i) the compressor (53) is in operation, and (ii) the first connection pipe (58) and the suction side connection pipe (57) are four-way switching valves (55). (Iii) The temperature difference between the temperature Ts of the refrigerant flowing through the suction side connecting pipe (57) and the temperature T4e of the refrigerant flowing through the first connecting pipe (58) is larger than the predetermined temperature Tr. When these three states continue for a predetermined time, it is determined that the four-way switching valve (55) has a large leak and has failed.

  That is, when the compressor (53) is in operation and the four-way switching valve (55) is in the second state, the first connection pipe (58) is connected to the suction side of the compressor (53) by the four-way switching valve (55). The low-pressure refrigerant sucked into the compressor (53) should flow through the first connection pipe (58) and the suction-side connection pipe (57) connected to the connection pipe (57). If leakage occurs between the valve body (558) and the valve seat (554) in the four-way switching valve (55) when the four-way switching valve (55) is in the second state, the first port (P1 ) And high pressure refrigerant flowing out of the fourth port (P4) is mixed into low pressure refrigerant flowing in from the third port (P3) and out of the second port (P2). As a result, the refrigerant flowing out from the second port (P2) has a higher temperature than the refrigerant flowing into the four-way switching valve (55) through the third port (P3). That is, the temperature of the refrigerant flowing through the suction side connection pipe (57) through which the low-pressure refrigerant should be circulated, and the pipe connected to the suction side connection pipe (57) via the four-way switching valve (55) (this In the embodiment, the leakage state of the four-way switching valve (55) can be determined by monitoring the temperature difference with the temperature of the refrigerant flowing through the first connection pipe (58).

  However, in the leak determination unit (120) of the present embodiment, the temperature difference between the temperature Ts of the refrigerant flowing through the suction side connection pipe (57) and the temperature T4e of the refrigerant flowing through the first connection pipe (58) is greater than the predetermined temperature Tr. When it becomes larger, it is determined that the four-way selector valve (55) has failed due to leakage. In other words, the leakage determination unit (120) allows the four-way switching valve (55) to be free of some temperature differences, and the four-way switching valve (55) when the temperature difference becomes larger than the predetermined temperature Tr. ) Is determined to be malfunctioning. The predetermined temperature Tr is set based on the amount of leakage that the four-way selector valve (55) can tolerate.

  Therefore, according to this embodiment, the suction pipe temperature sensor (94) is provided in the suction side connection pipe (57), and the first connection pipe connecting the four-way switching valve (55) and the first adsorption heat exchanger (51). (58) is provided with a pipe temperature sensor (95), and when the suction side connection pipe (57) and the first connection pipe (58) are connected by the four-way switching valve (55), the suction pipe temperature sensor ( 94) and the pipe temperature sensor (95) can be compared to easily determine the leakage state of the four-way switching valve (55). Specifically, the temperature Ts of the refrigerant flowing through the suction side connection pipe (57) detected by the suction pipe temperature sensor (94) and the refrigerant flowing through the first connection pipe (58) detected by the pipe temperature sensor (95). The temperature of the refrigerant flowing through the pipe assumed to be flowing the same refrigerant by determining that the four-way switching valve (55) has failed due to leakage when the temperature difference from the temperature T4e becomes the predetermined temperature Tr. Based on the difference, a failure due to leakage of the four-way switching valve (55) can be easily detected.

  Further, the temperature difference of the refrigerant flowing through both pipes (57, 58) when the suction side connecting pipe (57) and the first connecting pipe (58) are connected via the four-way switching valve (55), that is, high pressure. By determining the leakage state of the four-way switching valve (55) based on the temperature difference of the low-pressure refrigerant before and after passing through the four-way switching valve (55) instead of the refrigerant, the leakage state of the four-way switching valve (55) is reliably determined Can be determined. That is, the high-pressure refrigerant and the low-pressure refrigerant blocked by the valve body (558) are circulated in the four-way switching valve (55). When a leak occurs in the valve body (558), the high-pressure refrigerant is mixed into the low-pressure refrigerant, so that the leakage state is sensitively reflected on the temperature and pressure of the low-pressure refrigerant. That is, the leakage state of the four-way switching valve (55) is determined not by the temperature difference between the high-pressure refrigerant before and after passing through the four-way switching valve (55) but by the temperature difference between the low-pressure refrigerant before and after passing through the four-way switching valve (55). Thus, the leakage state of the four-way selector valve (55) can be sensitively determined.

  Furthermore, in this configuration in which the leakage state of the four-way switching valve (55) is determined based on the temperature difference between the low-pressure refrigerant before and after passing through the four-way switching valve (55), two adsorptions are performed as in the present embodiment. A pipe temperature sensor (95) is attached only to one of the first and second connecting pipes (58, 59) connected to the heat exchanger (51, 52), specifically, to the first connecting pipe (58). When provided, when the second connection pipe (59) is connected to the suction side connection pipe (57) by the four-way switching valve (55), the leakage state of the four-way switching valve (55) cannot be determined. The leakage state of the four-way switching valve (55) can be determined only when the first connection pipe (58) is connected to the suction side connection pipe (57). However, in the humidity control apparatus (10) that performs the humidity control operation while alternately switching the refrigerant circulation direction in the refrigerant circuit (50) at predetermined time intervals as in the present embodiment, the four-way switching valve (55) Since the first connection pipe (58) is frequently connected to the suction side connection pipe (57), the leakage state of the four-way switching valve (55) can be frequently determined. As a result, it is possible to reliably determine the leakage state of the four-way switching valve (55). And since it is only necessary to provide a temperature sensor in one of the first and second connecting pipes (58, 59), the number of parts is reduced and the configuration of the humidity control apparatus (10) is simplified. Can do.

  In addition, the leakage determination unit (120) detects that the temperature Ts of the refrigerant flowing through the suction side connecting pipe (57) is higher than the temperature T4e of the refrigerant flowing through the first connecting pipe (58). Instead of determining a failure, it is determined that the four-way switching valve (55) has failed by determining that the temperature difference between the temperature Ts and the temperature T4e is greater than the predetermined temperature Tr. When there is no leak amount, it is determined that the four-way selector valve (55) has failed, and when the leak amount exceeds the allowable range (that is, when the temperature difference becomes larger than the predetermined temperature Tr). ) For the first time, it can be determined that the four-way selector valve (55) has failed. Further, it is determined that the four-way switching valve (55) is out of order, and by giving an allowable value to the temperature difference between the temperature Ts and the temperature T4e, the suction pipe temperature sensor (94) and the pipe temperature sensor (95) Even if there is an error in the detected value, it is possible to prevent erroneous determination that the four-way switching valve (55) has failed.

-Modification 1 of embodiment-
In the refrigerant circuit (50) of the present embodiment, a supercritical cycle in which the high pressure of the refrigeration cycle is set to a value higher than the critical pressure of the refrigerant may be performed. In that case, one of the first adsorption heat exchanger (51) and the second adsorption heat exchanger (52) operates as a gas cooler, and the other operates as an evaporator.

-Modification 2 of embodiment-
In the humidity control apparatus (10) of the present embodiment, the adsorbent carried on the first adsorption heat exchanger (51) and the second adsorption heat exchanger (52) is heated or cooled by the refrigerant. The adsorbent may be heated or cooled by supplying cold water or hot water to the first adsorption heat exchanger (51) and the second adsorption heat exchanger (52).

  In the embodiment, the pipe temperature sensor (95) is provided only in the first connection pipe (58) of the first and second connection pipes (58, 59), and the first connection pipe (58) is on the suction side. Although the leakage state of the four-way switching valve (55) is determined when the four-way switching valve (55) is controlled so as to be connected to the connecting pipe (57), the present invention is not limited to this. That is, as shown in FIG. 12, a pipe temperature sensor (95) is provided in both the first and second connection pipes (58, 59), and the suction side connection pipe (57) is controlled by switching control of the four-way switching valve (55). The configuration may be such that the leakage state of the four-way selector valve (55) is determined based on the detection result of the pipe temperature sensor (95) provided in the pipe that is assumed to be connected to the pipe. By doing so, as described above, not only when the four-way switching valve (55) is in the second state, but also when the four-way switching valve (55) is in the first state, that is, the leakage state of the four-way switching valve (55) is always determined. Can do.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a humidity control apparatus for adjusting indoor humidity.

It is a perspective view which abbreviate | omits a part of casing and an electrical component box from the humidity control apparatus seen from the front side. It is a schematic plan view, a right side view, and a left side view showing a humidity controller with a part thereof omitted. It is a piping system diagram showing the composition of a refrigerant circuit, (A) shows operation in the 1st operation, and (B) shows operation in the 2nd operation. It is sectional drawing which shows the structure of a four-way switching valve. It is a schematic explanatory drawing of the pilot valve connected to a four-way switching valve, (A) shows an OFF state, (B) shows an ON state. It is a schematic plan view, a right side view, and a left side view of the humidity control apparatus showing the air flow in the first operation of the dehumidifying ventilation operation. It is a schematic plan view, a right side view, and a left side view of the humidity control apparatus showing the air flow in the second operation of the dehumidifying ventilation operation. It is a schematic plan view, a right side view, and a left side view of a humidity control apparatus showing the air flow in the first operation of the humidification ventilation operation. It is a schematic plan view, a right side view, and a left side view of the humidity control apparatus showing the air flow in the second operation of the humidification ventilation operation. It is a schematic plan view, a right side view, and a left side view of a humidity control apparatus showing the flow of air in simple ventilation operation. It is a flowchart figure of the leak determination by a leak determination part. It is a piping system diagram which shows the structure of the refrigerant circuit which concerns on a modification.

10 Humidity control device
50 Refrigerant circuit
51 First adsorption heat exchanger
52 Second adsorption heat exchanger
55 Four-way selector valve
57 Suction side connection piping
58 1st connecting pipe (heat exchanger connecting pipe)
94 Suction pipe temperature sensor (downstream temperature detection means)
95 Piping temperature sensor (upstream temperature detection means)
110 Operation control unit (control unit)
120 Leak determination unit (leak determination means)

Claims (2)

Two adsorption heat exchangers (51, 52) performing an adsorption operation for adsorbing moisture and at least one performing a regeneration operation for desorbing moisture and a four-way switching valve (55) for switching the refrigerant circulation direction are connected. A refrigerant circuit (50) and a control unit (110) for controlling the four-way switching valve (55), wherein the control unit (110) alternately switches the circulation direction of the refrigerant by the four-way switching valve (55). A humidity control device that adjusts the humidity of the air passing through the adsorption heat exchanger (51, 52) and supplies it indoors while switching between the adsorption operation and the regeneration operation of the two adsorption heat exchangers (51, 52). There,
For the refrigerant passing through the four-way switching valve (55), temperature detection for detecting the temperature of the refrigerant before passing through the four-way switching valve (55) and the temperature of the refrigerant after passing through the four-way switching valve (55) Means (94,95);
Leak determination means (120) for determining the leakage state of the four-way switching valve (55) based on the temperature of the refrigerant before and after passing through the four-way switching valve (55) detected by the temperature detection means (94, 95). further comprising a door,
The temperature detecting means (94, 95) is an upstream side for detecting the temperature of the refrigerant flowing through the heat exchanger connecting pipe (58) connecting the four-way switching valve (55) and one of the adsorption heat exchangers (51). A temperature detection means (95), and a downstream temperature detection means (94) for detecting the temperature of the refrigerant flowing through the suction side connecting pipe (57) connecting the four-way switching valve (55) and the suction side of the compressor. Have
The leakage determination means (120) controls the control unit (110) to connect the four-way switching valve (55) to the suction side connection pipe (57) and the heat exchanger connection pipe (58). The leakage state of the four-way switching valve (55) is determined based on the detection result of the downstream temperature detection means (94) and the detection result of the upstream temperature detection means (95). Humidity control device. In claim 1 ,
The leakage determination means (120) includes a refrigerant before passing through the four-way switching valve (55) detected by the downstream temperature detection means (94), and the refrigerant detected by the upstream temperature detection means (95). When the temperature difference from the refrigerant after passing through the four-way switching valve (55) becomes larger than a predetermined value, it is determined that the four-way switching valve (55) has failed due to leakage. .

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