Ventilation device and ventilation method

Abstract

To enable efficient defrosting.SOLUTION: A ventilation device includes: a compressor; a first heat exchanger functioning as a condenser or an evaporator; a first air passage through which air taken from an outdoor space is supplied to an indoor space after passing through the first heat exchanger; a second heat exchanger functioning as a condenser or an evaporator; a second air passage through which air taken from the indoor space is exhausted to the outdoor space after passing through the second heat exchanger; a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by a refrigerant pipeline and a refrigerant flows; and a control unit which guides airflow in the indoor space to the second heat exchanger to increase a temperature of the second heat exchanger and outputs a predetermined instruction to an actuator which controls a state of the refrigerant of the refrigeration circuit so as to increase a temperature of the refrigerant flowing into the second heat exchanger when it is determined that frost is formed on the second heat exchanger.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a ventilation device and a ventilation method.

Background Art

[0002] Conventionally, while ventilating the indoor space by an exhaust fan and an air supply fan, outdoor air heat-exchanged with a refrigerant by a first heat exchanger is blown into the indoor space, and indoor air heat-exchanged with the refrigerant by a second heat exchanger is discharged outdoors. A ventilation and air-conditioning device is known (see Patent Document 1). The ventilation and air-conditioning device described in Patent Document 1 proposes a technique of defrosting by switching the refrigerant flow in the first heat exchanger and the second heat exchanger when defrosting is performed. When performing such defrosting, the heating operation is temporarily stopped.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the ventilation and air-conditioning device described in Patent Document 1, when temporarily stopped for defrosting, defrosting can be performed by radiating heat in the second heat exchanger by switching the operation, but it may take time.

[0005] An object of the present disclosure is to perform efficient defrosting.

Means for Solving the Problems

[0006] The present disclosure is a compressor, a first heat exchanger that functions as a condenser or an evaporator, a first air flow path that supplies air taken in from the outside to the indoor space after passing through the first heat exchanger, A second heat exchanger that functions as a condenser or an evaporator, a second air flow path that exhausts the air taken in from the indoor space to the outside after passing through the second heat exchanger, a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by refrigerant pipes and refrigerant flows inside, a control unit that outputs a predetermined command to an actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the second heat exchanger and the temperature of the refrigerant flowing into the second heat exchanger by guiding the air flow in the indoor space to the second heat exchanger when it is determined that the second heat exchanger is in a frosting state, and provides a ventilation device including the same.

[0007] According to the ventilation device, by guiding the air flow in the indoor space to the second heat exchanger and controlling the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger, the defrosting efficiency of the second heat exchanger is improved.

[0008] Regarding the above ventilation device, when it is determined that the second heat exchanger is in a frosting state, a predetermined command indicating that the compressor is to be stopped is output.

[0009] According to the ventilation device, by stopping the compressor, the temperature of the refrigerant in the second heat exchanger can be increased, so that the defrosting efficiency of the second heat exchanger is improved.

[0010] Regarding the above ventilation device, the number of the second heat exchangers is plural, the refrigerant circuit further has a first valve unit that adjusts the opening degree of the flow path connected to each second heat exchanger for each second heat exchanger, when it is determined that a predetermined second heat exchanger included in the plurality of second heat exchangers is in a frosting state, the control unit outputs a predetermined command to close the first valve unit corresponding to the predetermined second heat exchanger.

[0011] According to the ventilation device, by closing the first valve portion, the temperature of the refrigerant in the predetermined second heat exchanger can be increased, so that the defrosting efficiency of the second heat exchanger is improved.

[0012] According to the ventilation device, by closing the first valve portion, the temperature of the refrigerant in the predetermined second heat exchanger corresponding to the first valve portion can be increased, so that the defrosting efficiency of the second heat exchanger is improved.

[0013] Regarding the above ventilation device, When it is determined that a plurality of the second heat exchangers are in a frosting state, the control unit outputs the predetermined command so as to close a plurality of the first valve portions corresponding to the plurality of second heat exchangers determined to be in the frosting state in a predetermined order.

[0014] According to the ventilation device, by closing the first valve portion in a predetermined order, it is possible to suppress the second heat exchangers from defrosting simultaneously and suppress a reduction in comfort.

[0015] Regarding the above ventilation device, The refrigerant circuit is provided between the first heat exchanger and the second heat exchanger and has a second valve portion for adjusting the opening degree of the flow path. When it is determined that the second heat exchanger is in a frosting state while the second heat exchanger is functioning as an evaporator, the control unit outputs the predetermined command so as to increase the opening degree of the second valve portion compared to before it is determined to be in the frosting state.

[0016] According to the ventilation device, by increasing the opening degree of the second valve portion and closing the first valve portion in a predetermined order, it is possible to suppress the second heat exchangers from defrosting simultaneously and suppress a reduction in comfort.

[0017] Regarding the above ventilation device, While the second heat exchanger is functioning as an evaporator, a third valve portion is further provided downstream of the second heat exchanger in the flow of the refrigerant in the refrigerant circuit. When the control unit further determines that the second heat exchanger is in a frosting state while the second heat exchanger is functioning as an evaporator, the control unit outputs the predetermined command to reduce the opening degree of the third valve unit compared to before the state of being determined to be in a frosting state.

[0018] According to the ventilation device, by reducing the opening degree of the third valve unit, the temperature of the refrigerant flowing through the upstream second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0019] Regarding the above ventilation device, The refrigerant circuit has a bypass pipe that allows the refrigerant to flow from the compressor to the second heat exchanger without passing through the first heat exchanger while the second heat exchanger is functioning as an evaporator. When the control unit determines that the second heat exchanger is in a frosting state, the control unit outputs the predetermined command so that the refrigerant compressed by the compressor flows through the bypass pipe to the second heat exchanger.

[0020] According to the ventilation device, by flowing the refrigerant through the bypass pipe to the second heat exchanger, the temperature of the refrigerant flowing through the second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0021] Regarding the above ventilation device, As control for guiding the air flow in the indoor space to the second heat exchanger, the control unit controls a first guiding mechanism that can switch whether to guide air from the ceiling space adjacent to the upper part of the indoor space to the second heat exchanger, or controls a second guiding mechanism that can switch whether to guide air from the indoor space to the second heat exchanger.

[0022] According to the ventilation device, by flowing warm air through the second heat exchanger, the temperature of the refrigerant flowing through the second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0023] Regarding the above ventilation device, The ventilation device further includes a bypass guide mechanism for guiding the air whose heat has been exchanged by the first heat exchanger to the second heat exchanger. When it is determined that the second heat exchanger is in a frosting state, and when it is determined that the temperature of the air whose heat has been exchanged by the first heat exchanger is greater than a predetermined temperature, the control unit controls the bypass guide mechanism to guide the air whose heat has been exchanged to the second heat exchanger.

[0024] According to the ventilation device, by flowing warm air through the second heat exchanger via the bypass guide mechanism, the temperature of the refrigerant flowing through the second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0025] Regarding the above ventilation device, The number of the second heat exchangers is plural. For each of the second heat exchangers, a second air flow path for exhausting the air taken in from the indoor space to the outside is provided. Based on the conditions of each of the plurality of second heat exchangers, the control unit adjusts the air volume of the air flowing through the second air flow path corresponding to the second heat exchanger.

[0026] According to the ventilation device, by adjusting the air volume of the air flowing according to the conditions of each of the plurality of second heat exchangers, simultaneous defrosting of the second heat exchangers can be suppressed, and a reduction in comfort can be suppressed.

[0027] Regarding the above ventilation device, When it is determined that the degree of frosting of one of the plurality of second heat exchangers is greater than that of the other second heat exchanger, the control unit increases the first air volume of the second air flow path corresponding to one of the second heat exchangers compared to the second air volume of the second air flow path corresponding to the other second heat exchanger.

[0028] According to the ventilation device, by performing defrosting of the second heat exchanger according to the degree of frosting of the second heat exchanger, a reduction in comfort can be suppressed.

[0029] Regarding the above ventilation device, According to the ventilation device, when the control unit performs control to increase the first air volume, the control unit performs control to decrease the second air volume as compared with before the control to increase the first air volume.

[0030] According to the ventilation device, it is possible to suppress the indoor space from becoming negative pressure and maintain comfort.

[0031] Regarding the above ventilation device, When it is determined that the second heat exchanger is in a frosting state, the control unit outputs a signal to increase the temperature set for the air conditioner provided in the indoor space to the air conditioner.

[0032] According to the ventilation device, by increasing the temperature set for the air conditioner, the temperature of the refrigerant flowing through the second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0033] Regarding the above ventilation device, It is provided with a switching mechanism for switching whether to supply air to the air flowing through the second air flow path from the indoor space or from the outdoor, The control unit controls the switching mechanism to supply air from the higher of the temperatures detected from the indoor space and the outdoor.

[0034] According to the ventilation device, by supplying air from the higher of the temperatures and flowing warm air through the second heat exchanger, the temperature of the refrigerant flowing through the second heat exchanger is increased, and the defrosting efficiency of the second heat exchanger is improved.

[0035] Regarding the above ventilation device, After receiving a signal indicating that the air conditioner performs a defrosting operation, when it is determined that the second heat exchanger is in a frosting state, the control unit suppresses outputting the predetermined command to an actuator that controls the state of the refrigerant in the refrigerant circuit.

[0036] According to the ventilation device, by suppressing defrosting of the second heat exchanger, simultaneous defrosting of the air conditioner and the ventilation device can be suppressed, and reduction in comfort can be suppressed.

[0037] Regarding the above ventilation device, When the control unit further receives a signal indicating that the air conditioner performs a defrosting operation, the control unit performs control to increase the air volume of the air supply from the first air flow path to the indoor space compared to before receiving the signal indicating that the air conditioner performs a defrosting operation, and performs control to increase the air volume of the exhaust from the second air flow path to the outside compared to before receiving the signal indicating that the air conditioner performs a defrosting operation.

[0038] According to the ventilation device, by increasing the air volume, the heating capacity of the ventilation device can be improved instead of the air conditioner, and comfort can be maintained.

[0039] Regarding the above ventilation device, When it is determined that the second heat exchanger is in a state of being frosted, the control unit further transmits a signal instructing the air conditioner not to perform a defrosting operation.

[0040] According to the ventilation device, by suppressing defrosting of the air conditioner, simultaneous defrosting of the air conditioner and the ventilation device can be suppressed, and reduction in comfort can be suppressed.

[0041] The present disclosure a compressor, a first heat exchanger functioning as a condenser or an evaporator, a first air flow path showing a flow path capable of discharging the air taken in from the outside to the indoor space after passing through the first heat exchanger, a second heat exchanger functioning as a condenser or an evaporator, a second air flow path showing a flow path capable of exhausting the air taken in from the indoor space to the outside after passing through the second heat exchanger, a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by a refrigerant pipe and refrigerant flows inside, While the second heat exchanger is functioning as an evaporator, when it is determined that the second heat exchanger is in a frosting state, a control unit outputs a predetermined command to cause the second heat exchanger to function as a condenser and the first heat exchanger to function as an evaporator, to a refrigerant circuit actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger, and provides a ventilation device including the control unit.

[0042] According to the ventilation device, by causing the second heat exchanger to function as a condenser, the defrosting efficiency of the second heat exchanger is improved.

[0043] Regarding the above ventilation device, While the second heat exchanger is functioning as an evaporator, when it is determined that the second heat exchanger is in a frosting state, the control unit outputs the predetermined command and switches the air flow in the first air flow path so as to exhaust air from the indoor space to the outside.

[0044] According to the ventilation device, by switching the air flow in the first air flow path so as to exhaust air to the outside, the temperature of the refrigerant flowing through the refrigerant circuit increases, so the defrosting efficiency of the second heat exchanger is improved.

[0045] Regarding the above ventilation device, While the second heat exchanger is functioning as an evaporator, when it is determined that the second heat exchanger is in a frosting state, the control unit further switches the flow in the second air flow path so as to supply air from the outside to the indoor space.

[0046] According to the ventilation device, by supplying air from the outside to the indoor space, it is possible to suppress the indoor space from becoming negative pressure and suppress a reduction in comfort.

[0047] Regarding the above ventilation device, A first casing that houses at least a part of the first heat exchanger and the first air flow path, a second heat exchanger and a second casing that houses at least a part of the second air flow path; the first casing and the second casing are separable.

[0048] According to the ventilation device, since the first casing and the second casing are separable, the layout is easy, and the burden during installation can be reduced.

[0049] The present disclosure is a compressor, a first heat exchanger functioning as a condenser or an evaporator, a first air flow path that supplies air taken in from the outside to an indoor space after passing through the first heat exchanger, a second heat exchanger functioning as a condenser or an evaporator, a second air flow path that exhausts air taken in from the indoor space to the outside after passing through the second heat exchanger, a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by refrigerant pipes and refrigerant flows inside, a plurality of ventilation devices provided in a predetermined space, and a ventilation method using the plurality of ventilation devices, a control unit acquires the frosting states of the plurality of second heat exchangers, when it is determined that the plurality of second heat exchangers are in a frosted state while the plurality of second heat exchangers are functioning as evaporators, generates a plurality of patterns for performing a defrosting operation on the plurality of second heat exchangers, acquires the situation of the predetermined space, and performs defrosting control of the second heat exchanger using any one of the plurality of generated patterns based on the frosting state and the situation of the predetermined space. A ventilation method is provided.

[0050] According to the ventilation method, defrosting control can be performed in an appropriate pattern, so the defrosting efficiency of the second heat exchanger is improved.

[0051] The present disclosure is A compressor, a first heat exchanger functioning as a condenser or an evaporator, a first air flow path for supplying air taken in from the outside into the indoor space after passing through the first heat exchanger, a second heat exchanger functioning as a condenser or an evaporator, a second air flow path for exhausting air taken in from the indoor space to the outside after passing through the second heat exchanger, and a control unit for controlling a ventilation device including a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by refrigerant pipes and refrigerant flows inside. When it is determined that the second heat exchanger is frosting, the control unit outputs a predetermined command to an actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the second heat exchanger and the temperature of the refrigerant flowing into the second heat exchanger by guiding the air flow in the indoor space to the second heat exchanger. Provide a ventilation method.

[0052] According to the ventilation method, by guiding the air flow in the indoor space to the second heat exchanger and controlling the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger, the defrosting efficiency of the second heat exchanger is improved.

Brief Description of the Drawings

[0053]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

[0054] Hereinafter, the present embodiment will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present disclosure, its applications, or its uses.

[0055] (First Embodiment) FIG. 1 is a diagram showing a configuration example of a ventilation device and an air conditioner according to the first embodiment. In the example shown in FIG. 1, a ventilation device 1 and an air conditioner 2 are provided to air-condition an indoor space.

[0056] In the present embodiment, as an example of the indoor space, an example having a living room space R11 and a ceiling space R12 will be described. However, the indoor space is not limited to the living room space R11 and the ceiling space R12, and may be any space inside a building, for example, it may have a space under the floor.

[0057] The living room space R11 is, for example, an office or an indoor living room in a house. The ceiling space R12 is a space adjacent to the upper side of the living room space R11. Since the ceiling space R12 exists above the living room space R11, warm air tends to gather.

[0058] The air conditioner 2 includes an outdoor unit 70 and two air-conditioning indoor units 81 and 82. Note that in this embodiment, the number of air-conditioning indoor units is not limited to two, and may be one or three or more.

[0059] The air conditioner 2 performs a vapor compression refrigeration cycle and is a device for cooling and heating the living space R11. The air conditioner 2 according to this embodiment is a device capable of both cooling and heating the living space R11. However, this embodiment is not limited to an air conditioner capable of both cooling and heating, and may be, for example, a device capable of only cooling.

[0060] The outdoor unit 70 and the two air-conditioning indoor units 81 and 82 are connected by a communication pipe F5. The communication pipe F5 includes a liquid refrigerant communication pipe and a gas refrigerant communication pipe (not shown). Thereby, a refrigerant circuit in which the refrigerant circulates between the outdoor unit 70 and the two air-conditioning indoor units 81 and 82 is realized. When the refrigerant circulates in the refrigerant circuit, a vapor compression refrigeration cycle is performed in the air conditioner 2.

[0061] The outdoor unit 70 is arranged outdoors. And the outdoor unit 70 is provided with a heat exchanger, and discharges the air heat-exchanged with the refrigerant flowing through the heat exchanger outdoors.

[0062] The air-conditioning indoor units 81 and 82 are provided with heat exchangers, and blow out the air heat-exchanged with the refrigerant flowing through the heat exchangers into the living space R11. In this embodiment, the air-conditioning indoor units 81 and 82 are ceiling-mounted types installed on the ceiling of the living space R11. In particular, the air-conditioning indoor units 81 and 82 of this embodiment are ceiling-embedded air-conditioning indoor units, and the air heat-exchanged from the ventilation openings 93A and 93B is blown out. In this embodiment, an example of providing the ventilation openings 93A and 93B on the ceiling will be described, but the positions where the ventilation openings 93A and 93B are provided are not particularly limited. Note that the air-conditioning indoor units 81 and 82 are not limited to the ceiling-embedded type, and may be ceiling-suspended types. Also, the air-conditioning indoor units 81 and 82 may be other than ceiling-mounted types such as wall-mounted types or floor-mounted types.

[0063] The ventilation device 1 includes an exhaust unit 10, an air supply unit 20, a compressor unit 50, refrigerant circuits F1, F2, F3, F4, an air supply passage P1, and a return air passage P2.

[0064] The ventilation device 1 is a device that supplies the taken-in outdoor air to the living room space R11 and exhausts the air taken in from the indoor space (including the living room space R11) to the outside. Thereby, the ventilation device 1 realizes the replacement of the air in the living room space R11.

[0065] Furthermore, the ventilation device 1 according to the present embodiment suppresses the temperature difference between the temperature of the air taken in from the outside and the temperature of the living room space R11 by exchanging heat between the exhaust unit 10 and the air supply unit 20.

[0066] The air supply passage P1 (an example of the first air passage) is a passage for supplying the air (outdoor air) taken in from the outside to the living room space R11 through the air supply unit 20 having the first heat exchanger 22 and then through the ventilation opening 92. In this embodiment, an example in which the ventilation opening 92 is provided on the ceiling will be described, but the position where the ventilation opening 92 is provided is not particularly limited.

[0067] The return air passage P2 (an example of the second air passage) is a passage for exhausting the air (return air) taken in from the ventilation opening 91 of the living room space R11 to the outside after passing through the exhaust unit 10 having the second heat exchanger 12. In this embodiment, an example in which the ventilation opening 91 is provided on the ceiling will be described, but the position where the ventilation opening 91 is provided is not particularly limited.

[0068] The refrigerant circuits F1, F2, F3, F4 are circuits that connect the compressor unit 50, the first heat exchanger 22 of the air supply unit 20, and the second heat exchanger 12 of the exhaust unit 10 by refrigerant pipes and allow refrigerant to flow inside.

[0069] The control unit 52 of the compressor unit 50, the control unit 23 of the air supply unit 20, and the control unit 13 of the exhaust unit 10 are connected by a signal line S1 shown by a dotted line in FIG. 1. Thereby, information can be transmitted and received among the control unit 52 of the compressor unit 50, the control unit 23 of the air supply unit 20, and the control unit 13 of the exhaust unit 10.

[0070] The compressor unit 50 includes a drive motor 51 and a control unit 52, and controls the circulation of the refrigerant in the refrigerant circuits F1, F2, F3, F4 by compressing any one of the refrigerants in the refrigerant circuits F1, F2, F3, F4. For example, when the second heat exchanger 12 in the exhaust unit 10 functions as an evaporator, the compressor unit 50 compresses the refrigerant in the refrigerant circuit F2 to circulate the refrigerant in the refrigerant circuits F1, F2, F3, F4.

[0071] The drive motor 51 is a motor for rotating (driving) a compressor for compressing the refrigerant.

[0072] The control unit 52 controls the components within the compressor unit 50. For example, the control unit 52 outputs a command for rotating (driving) the compressor to the drive motor 51.

[0073] The air supply unit 20 includes a fan 21, a first heat exchanger 22, a control unit 23, and a temperature detection unit 24, and takes in outside air (OA) and supplies air (SA) to the living space R11.

[0074] The fan 21 functions to supply the taken-in outside air (OA) to the living space R11.

[0075] The first heat exchanger 22 functions as a condenser or an evaporator.

[0076] The temperature detection unit 24 detects the outdoor air temperature, the surface temperature of the first heat exchanger 22, and the temperature of the refrigerant flowing through the first heat exchanger 22.

[0077] The control unit 23 controls the internal configuration of the air supply unit 20. The control unit 23 performs various controls according to the detection results by the temperature detection unit 14. For example, the control unit 23 adjusts the function of the first heat exchanger 22 as a condenser or an evaporator according to the detection results of the temperature detection unit 24.

[0078] The exhaust unit 10 includes a fan 11, a second heat exchanger 12, a control unit 13, and a temperature detection unit 14, takes in the return air (RA) of the living room space R11, and exhausts it (EA) outdoors.

[0079] The fan 11 functions to exhaust the return air (RA) taken in from the living room space R11 outdoors.

[0080] The second heat exchanger 12 functions as a condenser or an evaporator.

[0081] The temperature detection unit 14 detects the outdoor air temperature, the surface temperature of the second heat exchanger 12, and the temperature of the refrigerant flowing through the second heat exchanger 12. Further, the temperature detection unit 14 may detect the temperature of the air in the living room space R11 and the temperature of the air in the ceiling space R12 via a sensor unit (not shown).

[0082] The control unit 13 controls the internal configuration of the exhaust unit 10. The control unit 13 performs various controls according to the detection results by the temperature detection unit 14. For example, the control unit 13 adjusts the function of the second heat exchanger 12 as a condenser or an evaporator according to the detection results of the temperature detection unit 14.

[0083] The processing performed by the ventilation device 1 when the temperature is low will be described. When the temperature is low, the ventilation device 1 warms the outside air (OA) taken in from the outside in the air supply unit 20 and then supplies the conditioned air (SA) to the living room space R11. At the same time, the ventilation device 1 cools the return air (RA) taken in from the living room space R11 in the exhaust unit 10 and then exhausts the air (EA) to the outside. That is, the first heat exchanger 22 in the air supply unit 20 functions as a condenser, and the second heat exchanger 12 in the exhaust unit 10 functions as an evaporator. Since the temperature of the refrigerant flowing through the second heat exchanger 12 becomes low when the second heat exchanger 12 functions as an evaporator, there is a possibility that the second heat exchanger 12 will frost. Therefore, in the present embodiment, when it is determined that the second heat exchanger 12 has frosted, a defrosting operation is performed.

[0084] Specifically, while the second heat exchanger 12 is functioning as an evaporator, the control unit 13 of the exhaust unit 10 determines whether a predetermined criterion indicating that the second heat exchanger 12 is in a frosted state is satisfied based on the detection result by the temperature detection unit 14. As the predetermined criterion indicating that the second heat exchanger 12 is in a frosted state, it is conceivable that the state where the temperature of the refrigerant passing through the second heat exchanger 12 is equal to or lower than a predetermined value (for example, 0 degrees) continues for a certain period of time (for example, 10 minutes). Note that the present embodiment is not limited to the case where the refrigerant temperature is used to determine the frosted state, and the refrigerant pressure may be used for detection. Further, a further determination method for the frosted state may be used. For example, the control unit 13 may detect that the surface temperature of the second heat exchanger 12 has been equal to or lower than a predetermined value (for example, 0 degrees) for a certain period of time (for example, 10 minutes). As another example, the control unit 13 may determine based on the degree of coincidence between the image data captured by the imaging device of the surface of the second heat exchanger 12 and the image data in the normal state. Note that as long as it is possible to determine whether the second heat exchanger 12 is frosted, a method other than the above methods may be used.

[0085] When the control unit 13 of the exhaust unit 10 according to this embodiment determines that a predetermined standard is satisfied, it performs control for defrosting the second heat exchanger 12. As control for defrosting, the control unit 13 controls to increase the temperature of the second heat exchanger 12 by guiding the air flow in the living space R11 to the second heat exchanger 12. As specific control, the rotation of the fan 11 of the exhaust unit 10 is maintained. Thereby, the warm air in the living space R11 can flow through the second heat exchanger 12.

[0086] Furthermore, the control unit 13 of the exhaust unit 10 outputs a command (an example of a predetermined command) to stop the compressor in the compressor unit 50 to the drive motor 51 (an example of an actuator) of the compressor unit 50 via the control unit 52 of the compressor unit 50.

[0087] The drive motor 51 of this embodiment stops the compressor based on the command, so that the circulation of the refrigerant in the refrigerant circuits F1, F2, F3, and F4 stops.

[0088] As an example of control for defrosting the second heat exchanger 12, the control unit 13 according to this embodiment can perform defrosting by stopping the circulation of the refrigerant in the refrigerant circuits F1, F2, F3, and F4 and then flowing the warm air in the living space R11 through the second heat exchanger 12 to increase the temperature of the refrigerant flowing through the second heat exchanger.

[0089] By the way, in the defrosting of the conventional second heat exchanger, when the outside air temperature is low, the defrosting operation tends to be performed after reversing the cycle of the refrigerant circuit. In the defrosting operation switched to the reverse cycle, the air supply to the indoor space is on the evaporator side, so the temperature of the air supply becomes low, and it was common to stop the air supply. In this case, ventilation becomes insufficient. Also, when it is desired to ensure the air supply blowing, heating by an auxiliary heater or the like is required in the air supply blowing path, but there has been a problem that the thermal efficiency is low in such heating.

[0090] Therefore, in the present embodiment, after stopping the circulation of the refrigerant circuits F1, F2, F3, and F4, by using the warm air (heat) in the living space R11 for defrosting the second heat exchanger 12, highly efficient defrosting can be performed.

[0091] (Second Embodiment) In the above-described embodiment, an example in which one exhaust unit is provided has been described. However, the exhaust unit to be defrosted is not limited to one, and a plurality of units may be provided. Therefore, in the second embodiment, a configuration in which a plurality of exhaust units are provided and each of the exhaust units can be defrosted will be described.

[0092] FIG. 2 is a diagram showing a configuration example of a ventilation device, an air conditioner, and an upper control device according to the second embodiment. In the present embodiment, an example in which an upper control device provided above the air conditioner and the ventilation device performs control will be described. For configurations similar to those in the above-described embodiment, the same reference numerals are assigned and the description is omitted.

[0093] In the example shown in FIG. 2, an upper control device 100 is provided to perform cooperation between the ventilation device 1B and the air conditioner 2B.

[0094] The air conditioner 2B includes an outdoor unit 170 and two air conditioner indoor units 81 and 82. Note that the number of air conditioner indoor units in the present embodiment is not limited to two, and may be one or three or more.

[0095] The outdoor unit 170 includes a control unit 171 together with a heat exchanger (not shown).

[0096] The control unit 171 controls the entire air conditioner 2B. The control unit 171 also transmits and receives information to and from the upper control device 100. Then, the control unit 171 performs various controls according to the control signal from the upper control device 100.

[0097] The ventilation device 1B includes a first exhaust unit 110A, a second exhaust unit 110B, a first air supply unit 120A, a second air supply unit 120B, a compressor unit 150, refrigerant circuits F101, F102, F103, F104, a first air supply passage P101, a second air supply passage P102, a first exhaust passage P103, and a second exhaust passage P104.

[0098] The first air supply passage P101 supplies the air taken in from the outside to the living space R11 from the air supply port 92A after passing through the first air supply unit 120A having the first heat exchanger 22.

[0099] The second air supply passage P102 supplies the air taken in from the outside to the living space R11 from the air supply port 92B after passing through the second air supply unit 120B having the first heat exchanger 22.

[0100] The first exhaust passage P103 exhausts the air (return air) taken in from the air intake port 91A in the indoor space to the outside after passing through the first exhaust unit 110A having the second heat exchanger 12.

[0101] The second exhaust passage P104 exhausts the air (return air) taken in from the air intake port 91B in the indoor space to the outside after passing through the second exhaust unit 110B having the second heat exchanger 12.

[0102] The refrigerant circuits F101, F102, F103, F104 are circuits that connect the compressor unit 150, the first heat exchanger 22 of the first air supply unit 120A and the second air supply unit 120B, and the second heat exchanger 12 of the first exhaust unit 110A and the second exhaust unit 110B by refrigerant pipes and allow refrigerant to flow inside.

[0103] The control unit 152 of the compressor unit 150, the control unit 123 of the first air supply unit 120A, the control unit 123 of the second air supply unit 120B, the control unit 113A of the first exhaust unit 110A, and the control unit 113B of the second exhaust unit 110B are connected by a signal line S101 indicated by a dotted line. Thereby, information can be transmitted and received between the control unit 152, the two control units 123, the control unit 113A, and the control unit 113B.

[0104] The control unit 152 of the compressor unit 150 transmits the status of the ventilation device 1B received from the two control units 123, the control unit 113A, and the control unit 113B to the upper control device 100. Thereby, the upper control device 100 can realize control according to the status of the ventilation device 1B.

[0105] The first air supply unit 120A includes a fan 21, a first heat exchanger 22, a control unit 123, and a temperature detection unit 24, takes in outside air (OA), and supplies air (SA) from the ventilation port 92A to the living space R11.

[0106] The second air supply unit 120B includes a fan 21, a first heat exchanger 22, a control unit 123, and a temperature detection unit 24, takes in outside air (OA), and supplies air (SA) from the ventilation port 92B to the living space R11.

[0107] The control unit 123 controls the components within each air supply unit. Further, the control unit 123 transmits the detection results by the temperature detection unit 24 etc. within each air supply unit to the control unit 152 of the compressor unit 150. The control unit 152 of the compressor unit 150 recognizes the current status from the detection results and transmits the recognition results to the upper control device 100. Thereby, the upper control device 100 can recognize the status of the first air supply unit 120A and the second air supply unit 120B.

[0108] The first exhaust unit 110A includes a fan 11, a second heat exchanger 12, a control unit 113A, and a temperature detection unit 14, takes in return air (RA) from the ventilation port 91A of the living space R11, and exhausts it outdoors (EA).

[0109] The second exhaust unit 110B includes a fan 11, a second heat exchanger 12, a control unit 113B, and a temperature detection unit 14, takes in return air (RA) from the ventilation opening 91B of the living space R11, and exhausts it outdoors (EA).

[0110] The control unit 113A and the control unit 113B control the components within their respective exhaust units. Further, the control unit 113A and the control unit 113B transmit the detection results by the temperature detection unit 14 etc. within their respective exhaust units to the control unit 152 of the compressor unit 150. The control unit 152 of the compressor unit 150 recognizes the current situation from the detection results and transmits the recognition result to the upper control device 100. Thereby, the upper control device 100 can recognize the situations of the first exhaust unit 110A and the second exhaust unit 110B.

[0111] The upper control device 100 performs various controls to coordinate the operation of the ventilation device 1B and the operation of the air conditioner 2B.

[0112] The upper control device 100 receives the situation of the air conditioner 2B from the control unit 171 of the outdoor unit 170 and receives the situation of the ventilation device 1B from the control unit 152 of the compressor unit 150. Then, the upper control device 100 performs various controls according to the situations of the air conditioner 2B and the ventilation device 1B.

[0113] Also, when the upper control device 100 recognizes that the second heat exchanger 12 of either the first exhaust unit 110A or the second exhaust unit 110B is frosting, it performs control to stop the circulation of the refrigerant for the frosted second heat exchanger 12. In this embodiment, the circulation of the refrigerant can be stopped for each second heat exchanger 12. Therefore, the refrigerant circuit will be described next.

[0114] FIG. 3 is a diagram showing the refrigerant circuit according to the second embodiment. In the example shown in FIG. 3, the flow of the refrigerant when the second heat exchangers 12 of the exhaust units 110A and 110B function as evaporators is shown. For the components having the same configuration as those in the above-described embodiment, the same reference numerals are assigned and the description is omitted.

[0115] In the example shown in FIG. 3, an air supply unit 120A, 120B, an exhaust unit 110A, 110B, and a compressor unit 150 are provided.

[0116] The air supply units 120A, 120B include a fan 21, a first heat exchanger 22, a control unit 123, a temperature detection unit 24, a drive motor 25, and an electric valve 26.

[0117] The drive motor 25 controls the air volume of the fan 21 under the control of the control unit 123.

[0118] The electric valve 26 functions as an expansion valve that adjusts the opening degree of the flow path through which the refrigerant flows in order to reduce the pressure of the refrigerant, and switches whether to reduce the pressure based on the control by the control unit 123. The electric valve 26 functions to reduce the pressure when the first heat exchanger 22 functions as an evaporator, and does not reduce the pressure when the first heat exchanger 22 functions as a condenser. As shown in FIG. 3, the electric valve (expansion valve) 26 is provided in the flow path connected to the first heat exchanger 22 for each first heat exchanger.

[0119] The exhaust unit 110A includes a fan 11, a second heat exchanger 12, a control unit 113A, a temperature detection unit 14, a drive motor 15, and an electric valve 16.

[0120] The exhaust unit 110B includes a fan 11, a second heat exchanger 12, a control unit 113B, a temperature detection unit 14, a drive motor 15, and an electric valve 16.

[0121] The drive motor 15 controls the air volume of the fan 11 under the control of the control unit 113A or the control unit 113B.

[0122] The electric valve 16 functions as an expansion valve that adjusts the opening degree of the flow path through which the refrigerant flows in order to reduce the pressure of the refrigerant, and switches whether to reduce the pressure based on the control by the control unit 113A or the control unit 113B. The electric valve 16 functions to reduce the pressure when the second heat exchanger 12 functions as an evaporator, and does not reduce the pressure when the second heat exchanger 12 functions as a condenser. As shown in FIG. 3, the electric valve (expansion valve) 16 is provided in the flow path connected to the second heat exchanger 12 for each second heat exchanger.

[0123] The compressor unit 150 is provided with a drive motor 51, a control unit 152, a compressor 53, a four-way valve 54, an electric valve 55, and a bypass electric valve 56.

[0124] The compressor 53 compresses the refrigerant flowing through the refrigerant circuit.

[0125] The drive motor 51 is an actuator that drives the compressor 53. The drive motor 51 according to the present embodiment drives the compressor 53 at a rotation speed controlled by the control unit 152.

[0126] The control unit 152 controls the configuration inside the compressor unit 150. For example, the control unit 152 controls the drive motor 51 and the four-way valve 54 shown below.

[0127] The four-way valve 54 functions as a valve that switches the outflow destination of the refrigerant compressed by the compressor 53 from the refrigerant circuit F101 and the refrigerant circuit F104. For example, when the second heat exchanger 12 is caused to function as an evaporator based on the control of the control unit 152, the four-way valve 54 is switched so that the refrigerant compressed by the compressor 53 flows into the refrigerant circuit F101.

[0128] The electric valve 55 functions as a valve that performs opening and closing control of the refrigerant circuit according to the control from the control unit 152. When the second heat exchanger 12 functions as an evaporator, the electric valve 55 is in a closed state where the refrigerant does not flow.

[0129] The control units 113A and 113B output the detection results by the temperature detection unit 14 to the control unit 152 of the compressor unit 150.

[0130] Then, the control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating that the second heat exchanger 12 is frosting is satisfied from the input detection results. Note that the description of the predetermined criterion is omitted as it is the same as in the first embodiment.

[0131] When it is determined that the control units 113A and 113B of the exhaust units 110A and 110B according to the present embodiment satisfy the predetermined criterion, they notify the host control device 100 that the second heat exchanger 12 of the exhaust units 110A and 110B has frosted. Thereby, the host control device 100 can recognize that the second heat exchanger 12 is frosting.

[0132] Then, as control to defrost the second heat exchanger 12, the host control device 100 outputs a control signal (an example of a predetermined command) to close the motor-operated valve 16 existing upstream of the second heat exchanger 12 to the exhaust unit (the first exhaust unit 110A or the second exhaust unit 110B) including the frosted second heat exchanger 12.

[0133] Then, the control unit (control unit 113A or control unit 113B) of the exhaust unit (the first exhaust unit 110A or the second exhaust unit 110B) receives a control signal to close the motor-operated valve 16 from the host control device 100 via the compressor unit 150. In this case, the control unit (control unit 113A or control unit 113B) of the exhaust unit (the first exhaust unit 110A or the second exhaust unit 110B) outputs a signal to set the motor-operated valve 16 to the closed state to an actuator (an example of an actuator that controls the state of the refrigerant in the refrigerant circuit) that adjusts the opening degree of the motor-operated valve 16 (not shown), thereby performing control to set the motor-operated valve 16 to the closed state.

[0134] When the motor-operated valve 16 is in the closed state, the inflow of the refrigerant to the second heat exchanger 12 existing downstream of the motor-operated valve 16 is suppressed. The rotation control of the fan 11 is maintained as in the above-described embodiment.

[0135] That is, in the present embodiment, when there are a plurality of second heat exchangers 12, as an example of the control for defrosting the frosted second heat exchanger 12, by closing the electric valve 16 upstream of the frosted second heat exchanger 12, after stopping the inflow of cold refrigerant into the second heat exchanger 12, by flowing the warm air in the living space R11 to the second heat exchanger 12, the temperature of the refrigerant flowing through the second heat exchanger can be increased, and defrosting can be performed.

[0136] In the present embodiment, by using the warm air (heat) in the living space R11 for defrosting the second heat exchanger 12, defrosting with high thermal efficiency can be performed.

[0137] (Modification Example 1 of the Second Embodiment) In the above-described embodiment, an example of controlling to close the electric valve 16 corresponding to the second heat exchanger 12 when the second heat exchanger 12 is frosted has been described. By the way, when a plurality of second heat exchangers 12 are frosted, if the plurality of electric valves 16 are controlled to be in the closed state, the air conditioning capacity of the ventilation device 1B will decrease. Therefore, in this modification example, an example of controlling so that defrosting is not performed simultaneously on the plurality of second heat exchangers 12 when the plurality of second heat exchangers 12 are frosted will be described.

[0138] FIG. 4 is a sequence diagram showing the flow of processing performed among the upper control device 100, the compressor unit 150, and the exhaust unit groups 110A and 110B when each of the exhaust unit groups according to Modification Example 1 of the second embodiment is frosted.

[0139] First, the control unit 113A of the first exhaust unit 110A acquires the temperature of the refrigerant in the second heat exchanger 12 from the temperature detection unit 14 (S1401).

[0140] Then, the control unit 113A notifies the control unit 152 of the compressor unit 150 of the detected refrigerant temperature (1402).

[0141] Also, the control unit 113B of the second exhaust unit 110B acquires the temperature of the refrigerant in the second heat exchanger 12 from the temperature detection unit 14 (S1411).

[0142] Then, the control unit 113B notifies the control unit 152 of the compressor unit 150 of the detected refrigerant temperature (1412).

[0143] Based on the detected refrigerant temperature received from the control unit 113A of the first exhaust unit 110A and the control unit 113B of the second exhaust unit 110B, the control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating that the second heat exchanger 12 of the first exhaust unit 110A and the second exhaust unit 110B is frosting is satisfied (S1421). In the example shown in FIG. 4, it is determined that each of the second heat exchangers 12 of the first exhaust unit 110A and the second exhaust unit 110B satisfies the predetermined criterion. Note that the description of the predetermined criterion is omitted as it is the same as in the above-described embodiment.

[0144] The control unit 152 of the compressor unit 150 notifies the host control device 100 of the determination result indicating frosting (S1422).

[0145] Based on the received determination result, the host control device 100 determines the order for performing defrosting avoidance control for the first exhaust unit 110A and the second exhaust unit 110B (S1431). Any method may be used for determining the order. For example, control may be performed such that defrosting avoidance is performed first for the one with a higher possibility of frosting, or it may be determined according to the priority order pre-assigned to the first exhaust unit 110A and the second exhaust unit 110B. The example shown in FIG. 4 is an example determined to defrost the first exhaust unit 110A and the second exhaust unit 110B in this order.

[0146] The host control device 100 transmits a signal indicating closing control of the motor valve 16 of the first exhaust unit 110A to the control unit 152 of the compressor unit 150 (S1432).

[0147] Then, the control unit 152 of the compressor unit 150 transmits a signal indicating an instruction for closing control of the motor-operated valve 16 to the control unit 113A of the first exhaust unit 110A (S1423).

[0148] Thereby, the control unit 113A of the first exhaust unit 110A performs control to close the motor-operated valve 16 (S1403). As a result, the inflow of the refrigerant into the second heat exchanger 12 of the first exhaust unit 110A is suppressed.

[0149] After a predetermined time (for example, an appropriate time for the defrosting of the second heat exchanger 12 of the first exhaust unit 110A to be completed) has elapsed, the upper control device 100 transmits a signal indicating an instruction for opening control of the motor-operated valve 16 of the first exhaust unit 110A to the control unit 152 of the compressor unit 150 (S1433).

[0150] Then, the control unit 152 of the compressor unit 150 transmits a signal indicating an instruction for opening control of the motor-operated valve 16 to the control unit 113A of the first exhaust unit 110A (S1424).

[0151] Thereby, the control unit 113A of the first exhaust unit 110A performs control to open the motor-operated valve 16 (S1404). As a result, the inflow of the refrigerant into the second heat exchanger 12 of the first exhaust unit 110A is resumed.

[0152] The upper control device 100 transmits a signal indicating an instruction for closing control of the motor-operated valve 16 of the second exhaust unit 110B to the control unit 152 of the compressor unit 150 (S1434).

[0153] Then, the control unit 152 of the compressor unit 150 transmits a signal indicating an instruction for closing control of the motor-operated valve 16 to the control unit 113B of the second exhaust unit 110B (S1425).

[0154] Thereby, the control unit 113B of the second exhaust unit 110B performs control to close the motor-operated valve 16 (S1413). As a result, the inflow of the refrigerant into the second heat exchanger 12 of the second exhaust unit 110B is suppressed.

[0155] In this way, when it is determined that the plurality of second heat exchangers 12 are in a frosting state, the upper control device 100 transmits a signal to close the plurality of motorized valves 16 corresponding to the plurality of second heat exchangers determined to be in the frosting state in a predetermined order.

[0156] Therefore, when the control unit 152 of the compressor unit 150 and the upper control device 100 according to the present embodiment determine that a predetermined criterion is satisfied while the plurality of second heat exchangers 12 are functioning as evaporators, the inflow of refrigerant to any one of the plurality of second heat exchangers 12 is suppressed, and then the inflow of warm air from the living space R11 by the fan 11 is maintained, so that defrosting of the second heat exchanger 12 can be realized.

[0157] Furthermore, in the present embodiment, for each of the plurality of exhaust units, defrosting is performed in a predetermined order, so that simultaneous defrosting of the second heat exchangers 12 of the plurality of exhaust units is suppressed, and thus a further decrease in the room temperature of the living space R11 can be suppressed.

[0158] (Third Embodiment) Also, other methods may be used as the method for defrosting the second heat exchanger 12. Therefore, in the third embodiment, a different aspect of adjusting the opening degree of the motorized valve 16 inside the exhaust unit 310 will be described. Note that the configurations of the upper control device 100, the air conditioner 2B, and the ventilation device 1B according to the third embodiment are the same as those in the second embodiment, and the description thereof will be omitted.

[0159] As shown in FIG. 4, when the second heat exchanger 12 is functioning as an evaporator, the motorized valve 16 (an example of the second valve portion) is provided between the first heat exchanger 22 and the second heat exchanger 12.

[0160] When the second heat exchanger 12 functions as an evaporator, the electric valve 16 functions as a valve section that reduces the pressure of the high-pressure liquid refrigerant flowing out of the first heat exchanger 22 in order to make it easier to evaporate, according to the control of the control unit 313. Since the degree of opening of the electric valve 16 decreases, the pressure is reduced, and thus the temperature of the refrigerant decreases. In other words, the higher the degree of opening of the electric valve 16, the higher the temperature of the refrigerant.

[0161] While the second heat exchanger 12 is functioning as an evaporator, the upper control device 100 recognizes from the determination result from the control unit 152 of the compressor unit 150 that the second heat exchanger 12 is frosting. Note that the determination by the control unit 152 of the compressor unit 150 is the same as that in the above-described embodiments and modified examples, and thus the description thereof is omitted.

[0162] Then, the upper control device 100 outputs a control signal to increase the degree of opening of the electric valve 16 to the exhaust unit (for example, the first exhaust unit 110A or the second exhaust unit 110B) including the second heat exchanger 12 determined to be frosting, as compared with before the determination of frosting.

[0163] When the control unit 113A of the first exhaust unit 110A or 113B of the second exhaust unit 110B receives the control signal, it outputs a control signal (an example of a predetermined command) to an actuator (an example of an actuator that controls the state of the refrigerant in the refrigerant circuit) that adjusts the degree of opening of the electric valve 16 (not shown), to increase the degree of opening of the electric valve 16, as compared with before the determination of frosting.

[0164] Thereby, the temperature of the refrigerant flowing through the second heat exchanger 12 increases. In addition, warm air flows into the second heat exchanger 12 from the living space R11 by the fan 11. Thereby, defrosting of the second heat exchanger 12 can be realized.

[0165] (Modification Example 1 of the Third Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiments. Therefore, in Modification 1 of the third embodiment, an example of adjusting the refrigerant pressure with an electric valve provided downstream of the exhaust unit will be described.

[0166] The configuration of Modification 1 of the third embodiment has the same configuration as that of the second embodiment described above except for the refrigerant circuit.

[0167] FIG. 5 is a diagram showing a refrigerant circuit according to Modification 1 of the third embodiment. In the example shown in FIG. 5, the flow of the refrigerant when the second heat exchangers 12 of the exhaust units 110A and 110B function as evaporators is shown. Note that the same reference numerals are assigned to the same configurations as those in the above-described embodiments, and the description thereof is omitted.

[0168] In the example shown in FIG. 5, when the second heat exchangers 12 of the exhaust units 110A and 110B function as evaporators, electric valves 161 and 162 (an example of the third valve portion) are provided downstream of each of the second heat exchangers 12 of the exhaust units 110A and 110B.

[0169] The electric valves 161 and 162 are provided on the downstream side of the refrigerant flowing through the second heat exchanger 12 and have a mechanism capable of adjusting the refrigerant flow rate.

[0170] Then, the control unit 152 of the compressor unit 150 according to this modification determines whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied based on the temperature of the refrigerant flowing through the second heat exchanger 12 while the second heat exchanger 12 functions as an evaporator. Note that the predetermined criterion is the same as that in the above-described embodiments, and the description thereof is omitted. The control unit 152 of the compressor unit 150 notifies the upper control device 100 of the determination result.

[0171] In this modified example, when the upper control device 100 recognizes the existence of the second heat exchanger 12 that satisfies a predetermined standard, the control unit (control unit 113A or control unit 113B) of the exhaust unit (for example, the first exhaust unit 110A or the second exhaust unit 110B) including the second heat exchanger 12 is output with a control signal (predetermined command) for reducing the opening degree of the electric valve (electric valve 161 or electric valve 162) compared to before satisfying the predetermined standard. Thereby, the control unit (control unit 113A or control unit 113B) outputs a control signal (an example of a predetermined command) to an actuator (an example of an actuator for controlling the state of the refrigerant in the refrigerant circuit) that adjusts the opening degree of the electric valve (electric valve 161 or electric valve 162), thereby reducing the opening degree of the electric valve (electric valve 161 or electric valve 162).

[0172] In this way, in this modified example, separately from the electric valve 16 provided upstream of the second heat exchanger 12, an electric valve for adjusting the refrigerant flow rate is provided downstream of the second heat exchanger 12.

[0173] By reducing the opening degree of the electric valve (electric valve 161 or electric valve 162), the pressure of the refrigerant flowing through the second heat exchanger 12 existing upstream of the electric valve (electric valve 161 or electric valve 162) can be increased. Thereby, the evaporation temperature of the refrigerant flowing through the second heat exchanger 12 can be increased. Also, warm air in the living space R11 continuously flows into the second heat exchanger 12 by the fan 11. Therefore, defrosting of the second heat exchanger 12 can be realized.

[0174] (Fourth Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiments. In the fourth embodiment, an example of providing a bypass flow path (an example of a bypass pipe) in the refrigerant circuit will be described. In the fourth embodiment, compared to the third embodiment, an example is assumed in which the number of exhaust units 110B is reduced by one, and two supply units 120A and 120B and one exhaust unit 110A are provided. Other configurations are the same as those in the third embodiment, and the description thereof will be omitted.

[0175] FIG. 6 is a diagram showing a refrigerant circuit according to a fourth embodiment. In the example shown in FIG. 6, the flow of refrigerant when the second heat exchanger 12 of the exhaust unit 110A functions as an evaporator is shown. Note that the same components as those in the above-described embodiment are assigned the same reference numerals, and the description thereof is omitted.

[0176] In the example shown in FIG. 6, an air supply unit 120A, 120B, an exhaust unit 110A, and a compressor unit 150 are provided.

[0177] The air supply units 120A, 120B include a fan 21, a first heat exchanger 22, a control unit 23, a temperature detection unit 24, a drive motor 25, and an electric valve 26.

[0178] The exhaust unit 110A includes a fan 11, a second heat exchanger 12, a control unit 113A, a temperature detection unit 14, a drive motor 15, and an electric valve 16.

[0179] In this modification, while the second heat exchanger 12 functions as an evaporator, the control unit 113A of the exhaust unit 110A outputs the detection result of the temperature detection unit 14 (the temperature of the refrigerant flowing through the second heat exchanger 12) to the control unit 152 of the compressor unit 150.

[0180] Based on the input temperature of the refrigerant flowing through the second heat exchanger 12, the control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied. Note that the predetermined criterion is the same as that in the above-described embodiment, and the description thereof is omitted. The control unit 152 of the compressor unit 150 notifies the upper control device 100 of the determination result.

[0181] In this modification, when the upper control device 100 recognizes that there is a second heat exchanger 12 that satisfies a predetermined criterion, as defrosting control of the second heat exchanger 12, the control unit 152 of the compressor unit 150 is output with a control signal for flowing refrigerant through the bypass passage F106.

[0182] The compressor unit 150 is provided with a drive motor 51, a control unit 152, a compressor 53, a four-way valve 54, an electric valve 55, and an electric bypass valve 156.

[0183] The control unit 152 controls the internal configuration of the compressor unit 150. For example, the control unit 152 controls the drive motor 51 and the four-way valve 54 shown below.

[0184] In the present embodiment, when the second heat exchanger 12 functions as an evaporator, a bypass flow path F106 is provided to directly flow the refrigerant compressed by the compressor 53 to the second heat exchanger 12 in order to increase the temperature of the refrigerant flowing through the second heat exchanger 12.

[0185] The bypass flow path F106 is provided as a flow path for the refrigerant that bypasses between the compressor 53 and the four-way valve 54 and the refrigerant circuit F103. That is, the bypass flow path F106 functions as a pipe that flows the refrigerant to the second heat exchanger 12 without passing through the first heat exchanger 22 while the second heat exchanger 12 functions as an evaporator.

[0186] The electric bypass valve 156 functions as a valve for switching whether or not to flow the refrigerant through the bypass flow path F106 according to the control from the control unit 152.

[0187] Specifically, when the upper control device 100 determines that the second heat exchanger 12 is frosting, a control signal for flowing the refrigerant through the bypass flow path F106 is output to the control unit 152 of the compressor unit 150.

[0188] Then, when the control unit 152 of the compressor unit 150 receives a control signal for flowing the refrigerant through the bypass flow path F106 from the upper control device 100, the control unit 152 outputs a control signal (an example of a predetermined command) to an actuator (an example of an actuator that controls the state of the refrigerant in the refrigerant circuit) that controls the opening degree of the electric bypass valve 156 (not shown), thereby performing control to open the electric bypass valve 156.

[0189] When the bypass electric valve 156 is in the open state, the refrigerant that has become a high-temperature and high-pressure gas by being compressed by the compressor 53 flows into the refrigerant circuit F103 through the bypass flow path F106. By passing through the bypass flow path F106, a part of the refrigerant that has become a high-temperature and high-pressure gas flows through the refrigerant circuit F103 without passing through the first heat exchanger 22. As a result, the temperature of the refrigerant flowing through the refrigerant circuit F103 rises. Therefore, the refrigerant with the increased temperature flows through the second heat exchanger 12.

[0190] That is, in this modified example, when a predetermined standard is satisfied, control is performed to cause a part of the refrigerant that has become a high-temperature and high-pressure gas by the compressor 53 to flow to the second heat exchanger 12 through the bypass flow path F106. Along with this control, warm air in the living space R11 flows through the second heat exchanger 12 by the fan 11. Thereby, defrosting of the second heat exchanger 12 can be realized.

[0191] (Modification Example 1 of the Fourth Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiments and modification examples. In Modification Example 1 of the Fourth Embodiment, an example in which a heater is provided in the refrigerant circuit will be described. Modification Example 1 of the Fourth Embodiment is an example in which a heater is provided on the refrigerant circuit (for example, the refrigerant circuit F103) instead of deleting the bypass flow path F106 and the bypass electric valve 56 as compared with the Fourth Embodiment. Note that other configurations are the same as those in the Fourth Embodiment, and the description thereof is omitted.

[0192] In this modified example, while the second heat exchanger 12 is functioning as an evaporator, the control unit 113A of the exhaust unit 110A outputs the detection result of the temperature detection unit 14 (the temperature of the refrigerant flowing through the second heat exchanger 12) to the control unit 152 of the compressor unit 150.

[0193] The control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied based on the temperature of the refrigerant flowing through the input second heat exchanger 12. Note that the description of the predetermined criterion is omitted as it is the same as in the above-described embodiment. The control unit 152 of the compressor unit 150 notifies the upper control device 100 of the determination result.

[0194] In this modification, when the upper control device 100 recognizes that there is a second heat exchanger 12 that satisfies a predetermined criterion, as defrosting control of the second heat exchanger 12, the control unit 152 of the compressor unit 150 is instructed to start heating the refrigerant circuit by a heater.

[0195] When the control unit 152 of the compressor unit 150 receives an instruction to start heating from the upper control device 100, it starts heating the heater.

[0196] As a result, the temperature of the refrigerant flowing through the refrigerant circuit F103 rises. Therefore, the refrigerant with the increased temperature flows into the second heat exchanger 12. Along with this control, warm air in the living space R11 flows into the second heat exchanger 12 by the fan 11. Thereby, defrosting of the second heat exchanger 12 can be realized.

[0197] (Modification 2 of the Fourth Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiment and modification. In Modification 2 of the Fourth Embodiment, an example of increasing the pressure of the refrigerant flowing through the refrigerant circuit will be described. Modification 2 of the Fourth Embodiment is an example having the same configuration as, for example, the Second Embodiment. Note that the description of other configurations is omitted as it is the same as in the Fourth Embodiment.

[0198] In this modification, while the second heat exchanger 12 functions as an evaporator, the control unit 113A of the exhaust unit 110A outputs the detection result of the temperature detection unit 14 (the temperature of the refrigerant flowing through the second heat exchanger 12) to the control unit 152 of the compressor unit 150.

[0199] The control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied based on the temperature of the refrigerant flowing through the input second heat exchanger 12. Note that the description of the predetermined criterion is omitted as it is the same as in the above-described embodiment. The control unit 152 of the compressor unit 150 notifies the upper control device 100 of the determination result.

[0200] In this modification, when the upper control device 100 recognizes that there is a second heat exchanger 12 that satisfies the predetermined criterion, as defrosting control of the second heat exchanger 12, the control unit 152 of the compressor unit 150 is instructed to increase the pressure of the compressor.

[0201] When the control unit 152 of the compressor unit 150 receives an instruction to increase the pressure from the upper control device 100, it outputs a control signal to the drive motor 51 to increase the pressure compared to before it was determined that frosting occurred, thereby performing control to increase the pressure of the refrigerant flowing through the refrigerant circuit.

[0202] As a result, the pressure of the refrigerant flowing through the refrigerant circuit F103 increases, so the temperature of the refrigerant also increases accordingly. The refrigerant with the increased temperature flows into the second heat exchanger 12, and at the same time, the warm air in the living space R11 flows into the second heat exchanger 12 by the fan 11. Therefore, defrosting of the second heat exchanger 12 can be realized.

[0203] (Fifth Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiment. In the fifth embodiment, an example of making the flow of the refrigerant circuit into a reverse cycle will be described. In the fifth embodiment, the description is omitted as it is the same as in the third embodiment.

[0204] In this embodiment, while the second heat exchanger 12 is functioning as an evaporator, the control unit 113A of the exhaust unit 110A outputs the detection result of the temperature detection unit 14 (the temperature of the refrigerant flowing through the second heat exchanger 12) to the control unit 152 of the compressor unit 150.

[0205] The control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied based on the temperature of the refrigerant flowing through the input second heat exchanger 12. Note that the description of the predetermined criterion is omitted as it is the same as in the above-described embodiment. The control unit 152 of the compressor unit 150 notifies the upper control device 100 of the determination result.

[0206] In the present embodiment, when the upper control device 100 recognizes that there is a second heat exchanger 12 that satisfies a predetermined criterion, as defrost control of the second heat exchanger 12, the control unit 152 of the compressor unit 150 is instructed to reverse the flow of the refrigerant.

[0207] When the control unit 152 of the compressor unit 150 receives an instruction from the upper control device 100 to reverse the flow of the refrigerant, it outputs a control signal (an example of a predetermined command) for switching the flow of the four-way valve 54 provided in the refrigerant circuit as shown in FIG. 3 to an actuator (an example of an actuator for controlling the state of the refrigerant in the refrigerant circuit) that drives the four-way valve 54 (not shown). As a result, the refrigerant compressed from the compressor is switched to flow to the exhaust units 110A and 110B. At that time, the opening degrees of the motor-operated valves 16 and 26 are also adjusted.

[0208] Then, the second heat exchangers 12 of the exhaust units 110A and 110B function as condensers while the compressed refrigerant flows through them. On the other hand, the first heat exchangers 22 of the air supply units 120A and 120B function as evaporators.

[0209] By the above-described control, the refrigerant flowing through the refrigerant circuit becomes reverse cycle, and the second heat exchanger 12 functions as a condenser, so that the temperature of the refrigerant flowing through the second heat exchanger 12 rises. Also, warm air in the living space R11 flows through the second heat exchanger 12 by the fan 11. Thereby, defrosting of the second heat exchanger 12 can be realized.

[0210] (Modification 1 of the Fifth Embodiment) In the fifth embodiment, the flow of the refrigerant circuit was in the reverse cycle, but the flow of air was not switched. Therefore, in Modification 1 of the fifth embodiment, an example in which the reverse cycle is used and the flow of air is switched will be described. Modification 1 of the fifth embodiment has the same configuration as the fifth embodiment.

[0211] In this modification, when the upper control device 100 recognizes the existence of the second heat exchanger 12 that satisfies a predetermined standard by the same procedure as in the fifth embodiment, the control unit 152 of the compressor unit 150 is instructed to reverse the flow of the refrigerant, and the control units 123 of the air supply units 120A and 120B are instructed to output a control signal for switching the flow of air by the fan 21 so as to exhaust from the living space R11 to the outside through the first air supply passage P101 and the second air supply passage P102.

[0212] In this modification, by the above-described switching control of the air flow, warm air can be made to flow into the first heat exchanger 22 functioning as an evaporator, so that the temperature of the refrigerant flowing through the refrigerant circuit can be increased. By increasing the temperature of the refrigerant flowing through the first heat exchanger 22 functioning as an evaporator, the temperature of the refrigerant flowing through the second heat exchanger 12 can also be increased. Therefore, the temperature of the refrigerant flowing through the second heat exchanger 12 can be further increased to improve the defrosting efficiency.

[0213] (Modification 2 of the fifth embodiment) In Modification 1 of the fifth embodiment, an example in which the air flow on the air supply units 120A and 120B side is switched was described. However, in Modification 1 of the fifth embodiment, the same control as before frosting was maintained for the air flow on the exhaust units 110A and 110B side. Therefore, in Modification 2 of the fifth embodiment, an example in which the air flow on the exhaust units 110A and 110B side is also switched will be described. Note that Modification 2 of the fifth embodiment has the same configuration as the fifth embodiment.

[0214] In this modified example, when the upper control device 100 recognizes the existence of the second heat exchanger 12 that satisfies a predetermined standard by the same procedure as in the fifth embodiment, it instructs the control unit 152 of the compressor unit 150 to reverse the refrigerant flow, and outputs a control signal to the control units 123 of the air supply units 120A and 120B to switch the air flow by the fan 21 so as to exhaust air from the living space R11 to the outside through the first air supply passage P101 and the second air supply passage P102. Moreover, the upper control device 100 outputs a control signal to the control unit 113A of the exhaust unit 110A and the control unit 113B of the exhaust unit 110B to switch the air flow by the fan 11 so as to supply air from the outside to the living space R11 through the first exhaust passage P103 and the second exhaust passage P104.

[0215] In this modified example, by the above-described switching control of the air flow, warm air is made to flow into the first heat exchanger 22 functioning as an evaporator, and air supplied from the outside flows into the second heat exchanger 12 functioning as a condenser.

[0216] That is, in this modified example, since the refrigerant cycle and the air supply and exhaust are all switched, it is possible to realize continuous ventilation while performing heat exchange, so that the comfort of the living space R11 can be maintained while defrosting the second heat exchanger 12.

[0217] (Sixth Embodiment) Defrosting of the second heat exchanger 12 may be performed using a method other than the above-described embodiments. In the sixth embodiment, an example of adjusting the air flow to the exhaust unit will be described.

[0218] FIG. 7 is a diagram showing a configuration example of a ventilation device and an air conditioner according to the sixth embodiment. In the example shown in FIG. 7, a ventilation device 1C and an air conditioner 2 are provided for air-conditioning an indoor space. The ventilation device 1C has an exhaust unit 210 that performs control different from that of the above-described embodiments, and an air supply unit 20. Note that the same components as those in the above-described embodiments are assigned the same reference numerals and the description thereof is omitted.

[0219] The return air flow path P202 (an example of the second air flow path) is a flow path for exhausting the air (return air) taken in from the ventilation opening 91 of the living room space R11 to the outside after passing through the exhaust unit 10 having the second heat exchanger 12.

[0220] In order to enable the intake of air from a plurality of rooms, the return air flow path P202 according to the present embodiment has two branches for the intake of air. They are respectively referred to as the first return air branch path P202A (an example of the second air flow path) and the second return air branch path P202B (an example of the third air flow path).

[0221] The first return air branch path (an example of the second air flow path) P202A is an air flow path provided for exhausting the air taken in from the living room space R11 to the outside after passing through the exhaust unit 10 having the second heat exchanger 12. The first return air branch path P202A takes in air from the ventilation opening 91 provided on the ceiling of the living room space R11.

[0222] The second return air branch path (an example of the third air flow path) P202B is an air flow path provided for exhausting the air taken in from the ceiling space R12 to the outside after passing through the exhaust unit 10 having the second heat exchanger 12. Regarding the second return air branch path P202B according to the present embodiment, an example in which the ceiling space R12 is a room serving as a different air intake destination from the first return air branch path P202A will be described. However, the air intake destination is not limited to the ceiling space R12, and it may be an underfloor space. Thus, the air intake destination by the second return air branch path P202B may be any room different from the living room space R11 among the indoor spaces.

[0223] Also, an opening / closing damper 240 is provided at the tip of the second return air branch path P202B. The opening / closing damper 240 is normally in a closed state. And the opening / closing damper 240 (an example of the first guide mechanism) can adjust the amount of air taken in from the ceiling space R12 by control via a signal line S202 from the control unit 13 provided in the exhaust unit 10.

[0224] The exhaust unit 210 includes a control unit 213 that performs processes different from those of the above-described embodiment.

[0225] The control unit 213 controls the internal configuration of the exhaust unit 210. The control unit 213 performs various controls according to the detection result by the temperature detection unit 14. For example, the control unit 213 adjusts the function of the second heat exchanger 12 as a condenser or an evaporator according to the detection result of the temperature detection unit 14.

[0226] Furthermore, the control unit 213 according to the present embodiment can adjust the amount of air taken in from the ceiling cavity R12 by controlling the opening / closing damper 240 based on the detection result of the temperature detection unit 14.

[0227] In the present embodiment, while the second heat exchanger 12 functions as an evaporator, the control unit 213 of the exhaust unit 210 determines whether or not the second heat exchanger 12 satisfies a predetermined criterion of frosting based on the detection result by the temperature detection unit 14. Note that the description of the predetermined criterion is omitted as being the same as that of the above-described embodiment.

[0228] When it is determined that the control unit 213 of the exhaust unit 210 according to the present embodiment satisfies the predetermined criterion, the temperature of the air in the ceiling cavity R12 is detected. When it is determined that the temperature of the air in the ceiling cavity R12 is higher than the temperature of the air in the living room space R11, the control unit 213, as a defrosting control of the second heat exchanger 12, controls the opening / closing damper 240 to open so that the air existing in the ceiling cavity R12 is guided to the second heat exchanger 12 through the second return branch path P202B. That is, since the ceiling cavity R12 exists above the living room space R11, warm air has gathered. Therefore, when it is determined that the second heat exchanger 12 is frosting, control is performed to open the opening / closing damper 240. By this control, the air obtained by mixing the warm air existing in the ceiling cavity R12 and the air existing in the living room space R11 is guided to the second heat exchanger 12.

[0229] As an example of the control for raising the temperature of the refrigerant flowing through the second heat exchanger 12, the control unit 13 according to the present embodiment controls so that the warm air in the ceiling space R12 flows to the second heat exchanger 12. Thereby, defrosting of the second heat exchanger 12 can be realized. Note that the output of a command to the actuator that controls the state of the refrigerant in the refrigerant circuit so as to raise the temperature of the refrigerant flowing into the second heat exchanger 12 is omitted from the description as it may use any of the methods described in the above-described embodiment.

[0230] (Modification Example 1 of the Sixth Embodiment) In the above-described embodiment, an example has been described in which the warm air in the ceiling space R12 is mixed with the air in the living space R11 using the opening / closing damper 240 and controlled to flow to the second heat exchanger 12. However, the sixth embodiment is not limited to the method of mixing the warm air in the ceiling space R12 with the air in the living space R11. In modification example 1 of the sixth embodiment, an example will be described in which only the warm air in the ceiling space R12 is controlled to flow to the second heat exchanger 12.

[0231] In this modification example, similar to the above-described embodiment, the return air flow path P202 branches into a first return air branch path P202A (an example of a second air flow path) and a second return air branch path P202B (an example of a third air flow path).

[0232] In the above-described embodiment, an example is given in which the opening / closing damper 240 is provided in the second return air branch path P202B. However, in this modification example, an opening / closing damper (an example of a second guide mechanism) is also provided in the first return air branch path P202A. Otherwise, it is the same as the sixth embodiment.

[0233] The opening / closing damper provided in the first return air branch path P202A is normally in an open state. Thereby, the return air (RA) in the living space R11 can be taken in. The opening / closing damper provided in the first return air branch path P202A can adjust the amount of air taken in from the living space R11 by control via a signal line (not shown) from the control unit 313 provided in the exhaust unit 310.

[0234] Then, when the control unit 213 of the exhaust unit 210 according to this modification determines that a predetermined criterion that the second heat exchanger 12 is frosting is satisfied, it detects the temperature of the air in the ceiling cavity R12. And when it determines that the temperature of the air in the ceiling cavity R12 is higher than the temperature of the air in the living space R11, the control unit 213 controls to open the on-off damper 240 and also controls to close the on-off damper provided in the first return air branch passage P202A.

[0235] Thereby, the intake of the return air (RA) in the living space R11 is suppressed, and the warm air existing in the ceiling cavity R12 flows into the second heat exchanger 12. Therefore, it is possible to improve the defrosting efficiency of the second heat exchanger 12.

[0236] (Seventh Embodiment) The flow of air to the exhaust unit may be adjusted using a method other than the sixth embodiment described above. Therefore, in the seventh embodiment, another aspect of adjusting the flow of air to the exhaust unit will be described.

[0237] FIG. 8 is a diagram showing a configuration example of a ventilation device and an air conditioner according to the seventh embodiment. In the example shown in FIG. 8, in order to air-condition the indoor space, a ventilation device 1D and an air conditioner 2 are provided. The ventilation device 1D has an exhaust unit 310 that performs control different from that of the above-described embodiments. Note that the same components as those in the above-described embodiments are assigned the same reference numerals and the description thereof is omitted.

[0238] The first return air passage P301 (an example of the second air passage) is a passage for exhausting the air (return air) taken in from the ventilation opening 91 of the living space R11 to the outside after passing through the exhaust unit 10 having the second heat exchanger 12.

[0239] Also, a first on-off damper 341 (an example of a switching mechanism) is provided at the tip portion of the first return air passage P301. The first on-off damper 341 is normally in an open state. And the first on-off damper 341 can adjust the amount of air taken in from the living space R11 by control via a signal line S302 from the control unit 313 provided in the exhaust unit 310.

[0240] The second return air flow path P302 is a flow path for exhausting to the outside after taking in air (return air) from the outside through the exhaust unit 10 having the second heat exchanger 12.

[0241] Also, a second on-off damper 342 (an example of a switching mechanism) is provided on the flow path of the second return air flow path P302 (an example of the second air flow path). The second on-off damper 342 is normally in a closed state. And the second on-off damper 342 can adjust the amount of air taken in from the outside by control via the signal line S202 from the control unit 313 provided in the exhaust unit 310.

[0242] The first on-off damper 341 and the second on-off damper 342 function as a mechanism for switching whether to supply air to the second heat exchanger 12 from the living space R11 or from the outside.

[0243] The exhaust unit 310 includes a control unit 313 that performs processes different from those of the above-described embodiment.

[0244] The control unit 313 controls the internal configuration of the exhaust unit 310. The control unit 313 performs various controls according to the detection result by the temperature detection unit 14. For example, the control unit 313 adjusts the function as a condenser or an evaporator of the second heat exchanger 12 according to the detection result of the temperature detection unit 14.

[0245] Furthermore, the control unit 313 according to the present embodiment changes the intake source of the air flowing into the second heat exchanger 12 by controlling the first on-off damper 341 and the second on-off damper 342 based on the detection result of the temperature detection unit 14.

[0246] In the present embodiment, while the second heat exchanger 12 is functioning as an evaporator, the control unit 313 of the exhaust unit 310 determines whether or not the second heat exchanger 12 satisfies a predetermined criterion of frosting based on the detection result by the temperature detection unit 14. Note that the predetermined criterion is the same as that of the above-described embodiment, and the description thereof is omitted.

[0247] When the control unit 313 of the exhaust unit 310 according to the present embodiment determines that a predetermined standard is satisfied, it detects the temperature of the air in the living space R11 and the outdoor air. When the temperature of the air in the living space R11 is higher than the outdoor air, the control of the first on-off damper 341 and the second on-off damper 342 is not performed.

[0248] Then, when it is determined that the temperature of the outdoor air is higher than the temperature of the air in the living space R11, the control unit 313 controls the second on-off damper 342 to open so that the air existing outdoors is guided to the second heat exchanger 12 through the second return air passage P302 as defrosting control of the second heat exchanger 12. Further, the control unit 313 controls the first on-off damper 341 to close in order to prevent the air from the living space R11 from flowing into the second heat exchanger 12 through the first return air passage P301.

[0249] That is, while the second heat exchanger 12 is functioning as an evaporator, when the second heat exchanger 12 is frosted, the control unit 313 controls the first on-off damper 341 and the second on-off damper 342 to supply air from the higher of the temperatures detected from the living space R11 and the outdoors.

[0250] When it is possible to take in warm air from the outdoors, the control unit 313 controls the first on-off damper 341 and the second on-off damper 342 to take in air from the outdoors.

[0251] In the present embodiment, for example, when the control unit 313 compares the temperature TA of the air around the suction port of the first heat exchanger 22, the temperature TB of the air in the living space R11, and the temperature TC of the air around the blowout port of the second heat exchanger 12, and determines that the air temperature TC > the air temperature TB > the air temperature TA, the above-described processing is performed.

[0252] Examples where the temperature TC of the air is higher than the temperature TB and the temperature TA of the air include cases where the outlet of the second heat exchanger 12 is on the south side of the building and the surrounding air is warmed by sunlight or the like, the inlet of the first heat exchanger 22 is on the north side of the building and the surrounding air is cooled in the shade, there is remaining snow that has not completely melted near the inlet of the first heat exchanger 22 in early spring and the surrounding air is cooled, and the duct between the second heat exchanger 12 and the outlet is installed long in the ceiling space R12, so the air passing through the duct may be warmed by the heat in the ceiling space R12.

[0253] In such a situation, the control unit 313 controls so that the warm outdoor air flows to the second heat exchanger 12. Thereby, defrosting of the second heat exchanger 12 can be realized. Note that the output of a command to the actuator that controls the state of the refrigerant in the refrigerant circuit so as to raise the temperature of the refrigerant flowing into the second heat exchanger 12 may use any of the methods described in the above-described embodiment, and the description thereof is omitted.

[0254] In the present embodiment, by causing the higher-temperature air among the temperatures detected from the living space R11 and the outdoors to flow into the second heat exchanger 12, the temperature of the second heat exchanger 12 can be further increased, and the defrosting efficiency can be improved.

[0255] (Eighth Embodiment) You may adjust the flow of air to the exhaust unit using a method other than the above-described embodiment. Therefore, in the eighth embodiment, a method of providing a bypass flow path for directly flowing air between the air supply unit and the exhaust unit will be described.

[0256] FIG. 9 is a diagram showing a configuration example of a ventilation device and an air conditioner according to the eighth embodiment. In the example shown in FIG. 9, a ventilation device 1E and an air conditioner 2 are provided to perform air conditioning of the indoor space. In the third embodiment, the same components as those in the above-described embodiment are assigned the same reference numerals, and the description thereof is omitted.

[0257] As shown in FIG. 9, a bypass flow path P402 is provided between the air supply unit 20 and the exhaust unit 410. The bypass flow path P402 includes a first bypass partial flow path P402A on the air supply unit 20 side from the air supply flow path P401, a third bypass partial flow path P402C on the exhaust unit 10 side from the return air flow path P403, and a second bypass partial flow path P402B that connects the first bypass partial flow path P402A and the third bypass partial flow path P402C.

[0258] And, an opening / closing damper 440 (an example of a bypass guiding mechanism) is provided on the second bypass partial flow path P4102B. The opening / closing damper 440 is normally in a closed state. And, the opening / closing damper 440 can guide the air heated by the air supply unit 20 directly to the exhaust unit 410 by control via a signal line S401 from a control unit 413 provided in the exhaust unit 410.

[0259] After taking in outside air (OA), the air supply unit 20 normally supplies air (SA) to the living space R11 through the first bypass partial flow path P402A and the air supply flow path P401.

[0260] The exhaust unit 410 includes a fan 11, a second heat exchanger 12, a control unit 413, and a temperature detection unit 14, takes in the return air (RA) of the living space R11 through the return air flow path P403 and the third bypass partial flow path P402C, and exhausts it (EA) outdoors.

[0261] The control unit 413 of the exhaust unit 410 according to this modification detects whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied while the second heat exchanger 12 is functioning as an evaporator. Note that the description of the predetermined criterion is omitted as it is the same as that in the above-described embodiment.

[0262] When the control unit 13 determines that a predetermined standard is satisfied, it further determines whether the temperature of the air after passing through the first heat exchanger 22 is higher than a predetermined temperature (which may be a preset reference value or the temperature of the air in the living space R11). The predetermined temperature is determined according to the embodiment. When the control unit 13 determines that the temperature of the air after passing through the first heat exchanger 22 is higher than the predetermined temperature, it controls to open the on-off damper 440.

[0263] As described above, when it is determined that the second heat exchanger 12 is in a frosting state, the control unit 413 according to this modification controls to open the on-off damper 440 when it is determined that the temperature of the air exchanged by the first heat exchanger 22 is higher than a predetermined temperature. As a result, the air heated in the exhaust unit 410 can flow directly through the bypass flow path P402 to the second heat exchanger 12, so that the defrosting efficiency of the second heat exchanger 12 can be improved. Note that the output of a command to the actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger 12 may use any of the methods described in the above-described embodiments, and the description thereof is omitted.

[0264] (Ninth Embodiment) You may adjust the air flow to the exhaust unit using a method other than the above-described embodiments. Therefore, in the ninth embodiment, the case of cooperating with the air conditioner 2 will be described.

[0265] In the present embodiment, similar to the second embodiment, an example including the ventilation device 1B, the air conditioner 2B, and the upper control device 100 is used. This embodiment has the same configuration as the second embodiment as shown in FIG. 2.

[0266] The control unit 113A and the control unit 113B control the configurations in their respective exhaust units. Further, the control unit 113A and the control unit 113B transmit the detection results by the temperature detection unit 14 and the like in their respective exhaust units to the control unit 152 of the compressor unit 150.

[0267] Based on the detection result, the control unit 152 of the compressor unit 150 determines whether or not a predetermined criterion indicating that the second heat exchangers 12 of the exhaust units 110A and 110B are in a frosting state is satisfied.

[0268] The control unit 152 of the compressor unit 150 transmits the determination result and the recognition result to the upper control device 100. Thereby, the upper control device 100 can recognize the status of the first exhaust unit 110A and the second exhaust unit 110B.

[0269] The upper control device 100 performs various controls to coordinate the operation of the ventilation device 1B and the operation of the air conditioner 2B.

[0270] For example, when the upper control device 100 recognizes that at least one of the second heat exchangers 12 of the first exhaust unit 110A and the second exhaust unit 110B is in a frosting state, the upper control device 100 outputs a control signal to increase the temperature currently set for the air conditioner 2B provided in the living room space R11.

[0271] The air conditioner 2B improves its heating capacity in accordance with the control signal. Thereby, the temperature of the air in the living room space R11 rises. Therefore, the temperature of the air flowing into the second heat exchanger 12 can be increased. Therefore, the defrosting efficiency of the second heat exchanger 12 can be increased.

[0272] Also, when there are multiple air-conditioning indoor units, the upper control device 100 may select an air-conditioning indoor unit that improves the heating capacity according to the arrangement of the air-conditioning indoor units. In the case of the example shown in FIG. 2, when the second heat exchanger 12 of the exhaust unit 110A is frosted, the upper control device 100 improves the heating capacity of the air-conditioning indoor unit 81 provided near the ventilation port 91A of the exhaust unit 110A, and when the second heat exchanger 12 of the exhaust unit 110B is frosted, the upper control device 100 may improve the heating capacity of the air-conditioning indoor unit 82 provided near the ventilation port 91B of the exhaust unit 110B. Note that the output of a command to the actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger 12 may use any of the methods described in the above-described embodiment, and thus the description thereof is omitted.

[0273] That is, when performing the control to increase the temperature of the refrigerant in the refrigerant circuit shown in the above-described embodiment, even when the temperature adjustment ability of the ventilation device 1B decreases, the comfort of the living space R11 can be maintained by improving the heating capacity of the air conditioner 2B.

[0274] (Tenth Embodiment) The flow of air to the exhaust unit may be adjusted using a method other than the above-described embodiment.

[0275] In the present embodiment, similar to the second embodiment, an example including the ventilation device 1B, the air conditioner 2B, and the upper control device 100 is used. The present embodiment has the same configuration as the second embodiment as shown in FIG. 2.

[0276] Similar to the above-described embodiment, the upper control device 100 can recognize the status of the first exhaust unit 110A and the second exhaust unit 110B from the determination result from the control unit 152 of the compressor unit 150.

[0277] When the upper control device 100 recognizes that at least one of the second heat exchangers 12 in the first exhaust unit 110A and the second exhaust unit 110B is frosting, the upper control device 100 outputs a control signal to increase the air volume of the fan 11 for the exhaust unit (for example, the first exhaust unit 110A or the second exhaust unit 110B) including the frosting second heat exchanger 12.

[0278] Thus, in the present embodiment, based on the situation of each of the plurality of second heat exchangers 12, the upper control device 100 controls the fan 11 corresponding to the second heat exchanger 12 to adjust the air volume of the air flowing through the second heat exchanger 12.

[0279] As a result, the amount of air flowing through the frosting second heat exchanger 12 increases, so defrosting of the second heat exchanger 12 can be realized. In other words, in the present embodiment, by increasing the air volume on the exhaust heat recovery machine side, the efficiency of heat exchange is increased, and by suppressing a decrease in the temperature of the refrigerant flowing through the second heat exchanger 12, defrosting is realized.

[0280] In the present embodiment, even when there are a plurality of second heat exchangers 12, according to the situation of each of the second heat exchangers 12, by adjusting the air volume of the air flowing through the second heat exchanger 12, while maintaining the comfort of the indoor space, defrosting according to the degree of frosting of the second heat exchanger 12 can be realized.

[0281] (Modification Example 1 of the Tenth Embodiment) In this modification example, an example will be described in which when a plurality of second heat exchangers 12 are frosting, the control is made different according to the degree of frosting of the plurality of second heat exchangers 12. It is assumed that the modification example 1 of the tenth embodiment has the same configuration as the tenth embodiment.

[0282] When the upper control device 100 according to this modification recognizes that frosting has occurred in a plurality of second heat exchangers 12, it acquires the frosting level of each of the plurality of second heat exchangers 12. The frosting level is, for example, a value set according to the degree of frosting of the second heat exchanger 12 based on the determination result by the control unit 152 of the compressor unit 150, and is a value set according to the time since frosting and the current refrigerant temperature.

[0283] Then, when it is determined that the frosting level (degree of frosting) of one second heat exchanger 12 is higher than that of the other second heat exchanger 12 among the plurality of second heat exchangers 12, the upper control device 100 increases the air volume (an example of the first air volume) of the fan 11 corresponding to the one second heat exchanger 12 compared to the air volume (an example of the second air volume) of the fan 11 corresponding to the other second heat exchanger 12.

[0284] Furthermore, when the upper control device 100 controls to increase the air volume of the fan 11 corresponding to one second heat exchanger 12, it may perform control to decrease the air volume of the fan 11 corresponding to the other second heat exchanger 12 compared to before the control to increase it. Thereby, since the total value of the air discharge amount is maintained, it is possible to suppress the indoor space R11 from becoming a negative pressure.

[0285] Then, after the defrosting of one second heat exchanger 12 is completed, the upper control device 100 performs control to increase the air volume of the fan 11 corresponding to the other second heat exchanger 12 and performs control to decrease the air volume of the fan 11 corresponding to the one second heat exchanger 12.

[0286] In this embodiment, since the one with the higher degree of frosting among the plurality of second heat exchangers 12 can be preferentially defrosted, it is possible to improve the defrosting efficiency.

[0287] (Modification 2 of the 10th Embodiment) Therefore, in Modification 2, a case will be described where, when increasing the amount of air exhausted from the exhaust unit group, the amount of air taken in by the air supply unit group from the outside is increased. Note that Modification 2 of the tenth embodiment is assumed to have the same configuration as the tenth embodiment.

[0288] Similar to the tenth embodiment, the control unit 152 of the compressor unit 150 according to this modification determines whether or not a predetermined criterion indicating that the second heat exchanger 12 of the first exhaust unit 110A and the second exhaust unit 110B is frosting is satisfied based on the temperature of the outside air received.

[0289] When the control unit 152 of the compressor unit 150 determines that any one or more of the first exhaust unit 110A and the second exhaust unit 110B satisfy a predetermined criterion, the host controller 100 issues an instruction to increase the air volume for the exhaust unit. The method of this instruction is the same as that of the tenth embodiment, and the description thereof will be omitted.

[0290] The host controller 100 according to this modification, instead of issuing an instruction to decrease the air volume as shown in Modification 1 of the tenth embodiment, instructs an increase in the amount of air (air volume) supplied to any one or more of the first air supply unit 120A and the second air supply unit 120B. This instruction to increase is issued from the host controller 100 to the control units 423 of the first air supply unit 120A and the second air supply unit 120B via the control unit 152 of the compressor unit 150.

[0291] The target for instructing an increase in the amount of air (air volume) supplied may be either one of the first air supply unit 120A and the second air supply unit 120B, or each of the first air supply unit 120A and the second air supply unit 120B. However, the host controller 100 adjusts so that the amount of air discharged from the first exhaust unit 110A and the second exhaust unit 110B is the same as the amount of air taken in by the first air supply unit 120A and the second air supply unit 120B.

[0292] Thus, when the upper control device 100 according to this modified example performs control to increase the amount of air flowing through any one of the plurality of second heat exchangers 12 included in the exhaust unit group for the fan 11 associated with that second heat exchanger 12, based on the increased amount of air, for the fan 21 included in the intake unit group, control is performed to increase the amount of air flowing through the first heat exchanger 22 as compared to before satisfying a predetermined standard. As a result, in this modified example, since the amount of air taken in and the amount of air exhausted are substantially the same, it is possible to suppress the indoor space R11 from becoming a negative pressure.

[0293] (11th Embodiment) The cooperation between the air conditioner and the ventilation device is not limited to the above-described control. Therefore, in the 11th embodiment, the case where the air conditioner starts a defrosting operation will be described. Note that the configuration of the 11th embodiment is assumed to have the same configuration as that of the 2nd embodiment.

[0294] The upper control device 100 receives the status of the air conditioner 2B from the control unit 171 of the outdoor unit 170 and receives the status of the ventilation device 1B from the control unit 152 of the compressor unit 150. Then, the upper control device 100 performs various controls according to the status of the air conditioner 2B and the status of the ventilation device 1B.

[0295] For example, when the upper control device 100 recognizes that the air conditioner 2B is performing a defrosting operation based on the information received from the control unit 171 of the outdoor unit 170, it performs control to improve the heating capacity of the ventilation device 1B.

[0296] That is, when the air conditioner 2B performs a defrosting operation, since the air conditioner 2B does not function as a heater, the temperature in the living room space R11 may decrease. On the other hand, when the air conditioner 2B performs a defrosting operation, in order to compensate for the reduction in the function of the air conditioner 2B, when the supply air temperature of the first supply air unit 120A and the second supply air unit 120B is increased, the temperature of the refrigerant flowing through the second heat exchanger 12 of the first exhaust unit 110A and the second exhaust unit 110B connected by the refrigerant circuits F101, F102, F103, and F104 decreases. In this case, the possibility of frosting on the second heat exchanger 12 of the first exhaust unit 110A and the second exhaust unit 110B increases.

[0297] Therefore, when the upper control device 100 receives a signal indicating that the air conditioner 2B is performing a defrosting operation, the upper control device 100 controls the supply air units 120A and 120B to increase the air volume of the supply air from the first supply air passage P101 and the second supply air passage P102 to the living room space R11 compared to before receiving the signal indicating that the air conditioner 2B is performing a defrosting operation, and controls the exhaust units 110A and 110B to increase the air volume of the exhaust to the outside from the first exhaust passage P103 and the second exhaust passage P104 compared to before receiving the signal indicating that the air conditioner 2B is performing a defrosting operation.

[0298] In this embodiment, when the air conditioner 2B is performing a defrosting operation, the upper control device 100 improves the heating capacity and suppresses the decrease in the temperature in the living room space R11 by increasing the air volume of the supply and exhaust of the ventilation device 1B without increasing the supply air temperature for the ventilation device 1B.

[0299] (11th Embodiment) In the above-described embodiment, an example in which the upper control device 100 controls one compressor unit 150 has been described. However, the upper control device 100 is not limited to controlling only one compressor unit. Therefore, in the seventh embodiment, an example in which the upper control device 100 controls a plurality of ventilation devices and a plurality of air conditioners will be described.

[0300] FIG. 10 is a diagram illustrating the arrangement of a group of devices including the upper control device 500 according to the tenth embodiment. In the example shown in FIG. 10, it includes at least living spaces R501, R502, R503, dressing rooms R511, R512, and a pipe shaft R521.

[0301] Ventilation openings 595A and 595B are respectively provided in the dressing rooms R511 and R512.

[0302] Also, as the air conditioner 2F, it includes three outdoor units 571, 572, and 573. The outdoor unit 571 is connected to four air-conditioning indoor units 581, 582, 583, and 584 by connection pipes (not shown). The outdoor unit 572 is connected to two air-conditioning indoor units 585 and 586 by connection pipes (not shown). The outdoor unit 573 is connected to two air-conditioning indoor units 587 and 588 by connection pipes (not shown).

[0303] Also, the three outdoor units 571 to 573 are connected to the upper control device 500 by signal lines. Thereby, the three outdoor units 571 to 573 can perform air-conditioning control according to the control of the upper control device 500.

[0304] The first ventilation device 1F_1 is a ventilation device provided in the living space R501, and includes a first compressor unit 550A, a first air supply unit 520A, and a first exhaust unit 510A.

[0305] The first air supply unit 520A supplies air (SA) from the ventilation opening 592A. The first exhaust unit 510A returns air (RA) from the ventilation opening 591A. The first compressor unit 550A, the first air supply unit 520A, and the first exhaust unit 510A are connected by a connection pipe F501. The connection pipe F501 includes a plurality of refrigerant connection pipes. Thereby, refrigerant can be circulated among the first compressor unit 550A, the first air supply unit 520A, and the first exhaust unit 510A.

[0306] Further, the first compressor unit 550A, the first air supply unit 520A, and the first exhaust unit 510A are connected by signal lines (not shown). Thereby, information can be transmitted and received between the units. Also, the configurations within the first compressor unit 550A, the first air supply unit 520A, and the first exhaust unit 510A are the same as those of the compressor unit 150, the first air supply unit 120A, and the first exhaust unit 110A shown in FIG. 2, and the description thereof is omitted.

[0307] The second ventilation device 1F_2 is a ventilation device provided in the living room space R502, and includes a second compressor unit 550B, a second air supply unit 520B, and a second exhaust unit 510B.

[0308] The second air supply unit 520B supplies air (SA) from the air inlet 592B. The second exhaust unit 510B returns air (RA) from the air inlet 591B. The second compressor unit 550B, the second air supply unit 520B, and the second exhaust unit 510B are connected by a communication pipe F502. The communication pipe F502 includes a plurality of refrigerant communication pipes. Thereby, the refrigerant can be circulated among the second compressor unit 550B, the second air supply unit 520B, and the second exhaust unit 510B.

[0309] Further, the second compressor unit 550B, the second air supply unit 520B, and the second exhaust unit 510B are connected by signal lines (not shown). Thereby, information can be transmitted and received between the units. Also, the configurations within the second compressor unit 550B, the second air supply unit 520B, and the second exhaust unit 510B are the same as those of the compressor unit 150, the first air supply unit 120A, and the first exhaust unit 110A shown in FIG. 2, and the description thereof is omitted.

[0310] The third ventilation device 1F_3 is a ventilation device provided in the living room space R503, and includes a third compressor unit 550C, a third air supply unit 520C, and a third exhaust unit 510C.

[0311] The third air supply unit 520C supplies fresh air (SA) from the air inlet 592C. The third exhaust unit 510C exhausts stale air (RA) from the air outlet 591C. The third compressor unit 550C, the third air supply unit 520C, and the third exhaust unit 510C are connected by a communication pipe F503. The communication pipe F503 includes a plurality of refrigerant communication pipes. Thereby, refrigerant can be circulated among the third compressor unit 550C, the third air supply unit 520C, and the third exhaust unit 510C.

[0312] Also, the third compressor unit 550C, the third air supply unit 520C, and the third exhaust unit 510C are connected by signal lines (not shown). Thereby, information can be transmitted and received between the units. Also, the configurations within the third compressor unit 550C, the third air supply unit 520C, and the third exhaust unit 510C are the same as those of the compressor unit 150, the first air supply unit 120A, and the first exhaust unit 110A shown in FIG. 2, and the description thereof is omitted.

[0313] As described above, in the present embodiment, a plurality of combinations of a compressor unit, an air supply unit, an exhaust unit, and a communication pipe are provided. The first compressor unit 550A, the second compressor unit 550B, and the third compressor unit 550C are arranged on the pipe shaft R521.

[0314] The upper control device 500 is connected to the first compressor unit 550A, the second compressor unit 550B, and the third compressor unit 550C by signal lines. Thereby, the upper control device 500 can recognize the states of the devices of the first ventilation device 1F_1 to the third ventilation device 1F_3 and perform control on each device.

[0315] With the above-described configuration, while the second heat exchangers 12 of each of the first exhaust unit 510A to the third exhaust unit 510C function as evaporators, the control units (not shown) of the first compressor unit 550A to the third compressor unit 550C receive the temperature of the refrigerant flowing through the second heat exchanger 12 from each of the first exhaust unit 510A to the third exhaust unit 510C.

[0316] Then, while the second heat exchanger 12 functions as an evaporator, the control units of the first compressor unit 550A to the third compressor unit 550C according to this embodiment determine whether or not a predetermined criterion indicating frosting of the second heat exchanger 12 is satisfied based on the temperature of the refrigerant in the second heat exchanger 12. Note that the description of the predetermined criterion is omitted as it is the same as that in the above-described embodiment.

[0317] When it is determined that the predetermined criterion is satisfied, the upper control device 500 raises the room temperature of the air conditioner 2F corresponding to the area (the same zone) where the exhaust unit including the frosted second heat exchanger 12 is provided.

[0318] For example, when it is determined that the second heat exchanger 12 of the exhaust unit 510C is frosted, the set temperature of the air conditioner 2F provided in the same living space R503 is raised. In particular, by raising the set temperature of the air conditioner indoor unit 582 provided in the vicinity of the ventilation opening 591C of the exhaust unit 510C, an increase in the defrosting efficiency of the second heat exchanger 12 of the exhaust unit 510C can be realized.

[0319] Furthermore, the capacity of the ventilation device can be decreased by the amount by which the capacity of the air conditioner 2F is increased. In other words, since the temperature of the refrigerant passing through the exhaust unit of the ventilation device can be raised, rapid defrosting of the heat exchanger can be realized. The method of raising the temperature of the refrigerant passing through the exhaust unit of the ventilation device is omitted as it is the same as that in the above-described embodiment.

[0320] Further, for the output of a command to an actuator that controls the state of the refrigerant in the refrigerant circuit so as to increase the temperature of the refrigerant flowing into the second heat exchanger 12 of the exhaust unit 510C, any method among the methods described in the above-described embodiments may be used. For example, as shown in the fifth embodiment, by performing control to reverse the flow of the refrigerant circuit including the second heat exchanger 12 of the exhaust unit 510C, the temperature of the refrigerant flowing through the second heat exchanger 12 may be increased. Further, control may be performed to increase the temperature of the refrigerant flowing through the second heat exchanger 12 while maintaining the forward cycle for the flow of the refrigerant circuit including the second heat exchanger 12 of the exhaust unit 510C.

[0321] For example, in the upper-level control device 100 according to the present embodiment, as defrosting of the second heat exchanger 12 of the exhaust unit 510C of the ventilation device 1F_3, control may be performed to increase the amount of air exhausted from the exhaust unit 510C as compared with before starting the defrosting operation of the air conditioner 2F. At that time, the upper-level control device 500 may perform control to decrease the amount of air exhausted from the exhaust unit 510A of the ventilation device 1F_1 and the amount of air exhausted from the exhaust unit 510B of the ventilation device 1F_2, which are different from the ventilation device 1F_3 in system. The control to increase the amount of air and the control to decrease the amount of air are the same as those in the above-described embodiments, and the description thereof is omitted. By this control, defrosting of the second heat exchanger 12 of the exhaust unit 510C is realized, and by maintaining the amount of air discharged, it is possible to suppress the negative pressure in the living spaces R501, R502, and R503.

[0322] In the present embodiment, by increasing the temperature of the living space, the temperature of the air flowing through the second heat exchanger 12 is increased, and the defrosting efficiency is increased.

[0323] In the present embodiment, when performing the defrosting operation of the ventilation devices 1F_1 to 1F_3, by improving the heating capacity of the air conditioner provided in the same area as the ventilation devices 1F_1 to 1F_3, the decrease in the heating capacity of the ventilation device is compensated, and comfort can be maintained.

[0324] (Modification Example 1 of the Eleventh Embodiment) In Modification Example 1 of the 11th embodiment, the case where the air conditioner 2F starts a defrosting operation will be described. In the above-described embodiment, an example in which, when it is determined that the second heat exchanger 12 is frosted, a predetermined command is output to the actuator that controls the state of the refrigerant in the refrigerant circuit has been described. In contrast, in the modification example of the present embodiment, even when it is determined that the state is frosted, if a predetermined condition is satisfied, the output of the predetermined command is suppressed.

[0325] After receiving a signal indicating that the air conditioner 2F is performing a defrosting operation, the upper control device 500 receives a determination result from the control units of the first compressor unit 550A to the third compressor unit 550C that it has been determined that the second heat exchanger 12 is frosted.

[0326] In this case, while the air conditioner 2F is performing a defrosting operation, the upper control device 500 suppresses outputting a predetermined command to the actuator that controls the state of the refrigerant in the refrigerant circuit in order to increase the temperature of the refrigerant flowing through the frosted second heat exchanger 12.

[0327] Further, while the air conditioner 2F is performing a defrosting operation, the upper control device 500 may perform control to increase the air volume of the fan 11 corresponding to the frosted second heat exchanger 12.

[0328] (Modification Example 2 of the 11th embodiment) As a further modification, while the air conditioner 2F is performing a defrosting operation, the upper control device 500 may transmit a command to the compressor unit (for example, the compressor unit 550C) to reduce the flow rate of the refrigerant to the second heat exchanger 12 determined to be likely to frost. Thereby, the progress of frosting can be suppressed. That is, by suppressing the progress of frosting of the second heat exchanger 12, it is possible to suppress a simultaneous defrosting operation with the air conditioner 2F for which the defrosting operation is currently being performed.

[0329] Thereby, it is possible to suppress the heating capacity of the first heat exchanger 22 of the air supply unit (for example, the air supply unit 520C) from stopping, and thus it is possible to maintain a minimum level of comfort.

[0330] As criteria for determining the possibility of frosting, for example, the surface temperature of the second heat exchanger 12 and the temperature of the indoor air in the living space (for example, the living space R505) are measured. It is conceivable that the surface temperature of the second heat exchanger 12 is lower than the dew point temperature of the air and the surface temperature of the second heat exchanger 12 is 0°C or lower. Note that as the temperature of the indoor air, it is conceivable to use, for example, the temperature measured by a sensor provided near the ventilation opening.

[0331] Furthermore, the upper control device 500 monitors the frosting states of the second heat exchangers 12 of the plurality of exhaust units and the frosting states of the plurality of air conditioners 2F, and performs a defrosting operation sequentially from the devices determined to be likely to have frosting, thereby shortening the time during which a plurality of devices simultaneously enter the defrosting operation or suppressing the occurrence of a plurality of devices simultaneously entering the defrosting operation.

[0332] (Modification Example 3 of the Tenth Embodiment) Similar to Modification Example 1 of the Eleventh Embodiment, the upper control device 500 according to Modification Example 3 of the Tenth Embodiment receives a signal indicating that a defrosting operation is to be performed from the air conditioner 2F, and then receives a determination result determined that the second heat exchanger 12 is in a frosted state from the control units of the first compressor unit 550A to the third compressor unit 550C.

[0333] In this case, while the air conditioner 2F is performing a defrosting operation, the upper control device 500 suppresses outputting a predetermined command to an actuator that controls the state of the refrigerant in the refrigerant circuit in order to increase the temperature of the refrigerant flowing through the frosted second heat exchanger 12.

[0334] Furthermore, when the upper control device 500 receives a signal indicating that a defrosting operation is to be performed from the air conditioner 2F, the upper control device 500 controls the air supply unit (for example, the air supply unit 520C) to increase the air volume of the air supply from the air supply path to the living space (for example, the living space R503) compared to before the air conditioner 2F performs a defrosting operation, and controls the exhaust unit (for example, the exhaust unit 510C) to increase the air volume of the exhaust from the second air flow path to the outside compared to before the air conditioner 2F performs a defrosting operation.

[0335] In this modification example, since the total of the intake air volume and the exhaust air volume is maintained, it is possible to suppress the indoor space from becoming negative pressure. Further, by increasing the air volume of the ventilation device, it is possible to suppress a decrease in heating capacity.

[0336] (Modification Example 4 of the 10th Embodiment) Furthermore, control may be performed to suppress simultaneous defrosting of the air conditioner 2F and the ventilation device.

[0337] When it is determined that the second heat exchanger 12 of the exhaust unit is in a frosting state, the upper control device 500 of this modification example starts defrosting control of the second heat exchanger 12. As the defrosting method, any method shown in the above-described embodiment may be used.

[0338] Furthermore, when starting the defrosting control of the second heat exchanger 12, the upper control device 500 transmits a control signal instructing not to perform the defrosting operation on the air conditioner 2F.

[0339] In this modification example, it is possible to suppress the air conditioner 2F and the ventilation device from performing the defrosting operation simultaneously. By suppressing simultaneous defrosting, it is possible to suppress a decrease in air conditioning capacity.

[0340] (11th Embodiment) Furthermore, when a plurality of ventilation devices are provided, when the second heat exchangers 12 of the plurality of ventilation devices are frosted, the defrosting control may be made different according to the degree of frosting of the second heat exchangers 12 of the plurality of ventilation devices.

[0341] In this embodiment, an example in which the upper control device 500 controls four ventilation devices will be described. Note that the number of air conditioners 2F controlled by the upper control device 500 is arbitrary.

[0342] FIG. 11 is a flowchart showing a processing procedure performed by the upper control device 500 according to the present embodiment. In the present embodiment, an example in which the upper control device 500 performs processing will be described, but the present invention is not limited to the upper control device 500, and processing may be performed on a centralized management server provided at a remote location or in the cloud.

[0343] The upper control device 500 acquires the detection results by the temperature detection unit 14 from each of the plurality of ventilation devices (S2201).

[0344] Based on the detection results, the upper control device 500 identifies the number of exhaust units (the second heat exchangers 12 thereof) having the frosted second heat exchangers 12 (S2202). For example, it may be determined that four exhaust units are frosted.

[0345] Then, the upper control device 500 determines whether the detection results of the frosted exhaust units are equal to or less than the first determination logic (S2203). As the first determination logic, for example, it is determined whether the evaporation temperature t of the refrigerant flowing through the second heat exchanger 12 of the exhaust unit is less than a predetermined value x1, or whether the pressure p of the refrigerant flowing through the second heat exchanger 12 of the exhaust unit is less than a predetermined value y1. Further, a further determination method may be used as the determination logic. For example, it may be determined whether the surface temperature t2 of the second heat exchanger 12 is less than a predetermined value z1. As another example, imaging means may capture the surface of the second heat exchanger 12, calculate the degree of coincidence between the captured image data and the image data in the normal state, and determine whether the difference is greater than w%.

[0346] When the upper control device 500 determines that the detection results are equal to or less than the first determination logic (S2203: Yes), it determines that the frost level of the exhaust unit is level 1 (S2204).

[0347] On the other hand, when the upper control device 500 determines that the detection result is greater than the first determination logic (S2203: No), it determines whether the detection result of the frosting exhaust unit is equal to or less than the second determination logic (S2205). As the second determination logic, for example, it is determined whether the evaporation temperature t of the refrigerant flowing through the second heat exchanger 12 of the exhaust unit is less than a predetermined value x2, or whether the pressure p of the refrigerant flowing through the second heat exchanger 12 of the exhaust unit is less than a predetermined value y2. Note that the predetermined value x1 < the predetermined value x2, and the predetermined value y1 < the predetermined value y2.

[0348] When the upper control device 500 determines that the detection result is equal to or less than the second determination logic (S2205: Yes), it determines that the frosting level of the exhaust unit is level 2 (S2206).

[0349] On the other hand, when the upper control device 500 determines that the detection result is greater than the first determination logic (S2205: No), it determines that the frosting level of the exhaust unit is level 3 (S2207).

[0350] After that, the upper control device 500 determines whether the frosting level has been set for all the frosting exhaust units (S2208). If it determines that not all have been set (S2208::No), the process is performed from S2203.

[0351] On the other hand, when the upper control device 500 determines that the frosting level has been set for all the frosting exhaust units (S2208: Yes), it calculates the time required for the defrosting operation for each exhaust unit (S2209). Note that the calculation method for the time required for the defrosting operation may be any well-known method, and any method may be used. Note that the time required for the defrosting operation may be preset for each frosting level.

[0352] Furthermore, the upper control device 500 calculates an index of required comfort in the living space based on the current situation of the living space (S2210). The current situation of the living space is, for example, the detection result of a sensor provided near the ventilation opening of the living space. The index of required comfort is an index of comfort required in the current living space. The index of comfort is determined according to, for example, the required value of the temperature blown out from the ventilation opening, the air volume required for ventilation, and the number of people present in the current living space. The higher the index of comfort, the more necessary it is to maintain the comfort of the living space.

[0353] The upper control device 500 determines whether the calculated index of required comfort is greater than the reference value k (S2211).

[0354] When the upper control device 500 determines that the calculated index of required comfort is greater than the reference value k (S2211: Yes), it sets to sequentially perform defrosting operations on the plurality of exhaust units (S2212). That is, the upper control device 500 suppresses simultaneous defrosting operations by setting to perform sequential defrosting operations, and maintains the comfort of the living space. Note that the order of performing defrosting is set according to the frosting level. For example, when there is 1 exhaust unit with a frosting level of 1, 2 exhaust units with a frosting level of 2, and 1 exhaust unit with a frosting level of 3, it is set to perform defrosting in the order of the exhaust unit with a frosting level of 1, one of the exhaust units with a frosting level of 2, the other of the exhaust units with a frosting level of 2, and the exhaust unit with a frosting level of 3.

[0355] On the other hand, when the upper control device 500 determines that the calculated required comfort index is equal to or less than the reference value k (S2211: No), it sets to perform simultaneous defrosting operations for a plurality of exhaust units (S2213). That is, the upper control device 500 terminates the defrosting operation earlier by setting the simultaneous defrosting operation. Note that the defrosting operations of all the exhaust units are not performed simultaneously. Also, the order of performing the defrosting operations may be set according to the defrosting level. For example, when there is 1 exhaust unit with a frosting level of 1, 2 exhaust units with a frosting level of 2, and 1 exhaust unit with a frosting level of 3, after simultaneously performing the defrosting operations of the exhaust unit with the frosting level of 1 and the exhaust unit with the frosting level of 3, it is set to simultaneously perform the defrosting operations of the 2 exhaust units with the frosting level of 2. With this setting, it is possible to balance the load related to the living space and the end of the defrosting operation.

[0356] Then, the upper control device 500 outputs an instruction for the defrosting operation for each exhaust unit according to the setting (S2214).

[0357] In this way, the upper control device 500 according to the present embodiment acquires the frosting state of the second heat exchanger 12, and when it is determined that the plurality of second heat exchangers 12 are in a frosted state while the plurality of second heat exchangers 12 are functioning as evaporators, a plurality of patterns for performing the defrosting operations of the plurality of second heat exchangers 12 are generated, and defrosting control is performed using any one of the plurality of generated patterns based on the frosting state of the plurality of second heat exchangers and the current situation of the living space.

[0358] In the present embodiment, the defrosting operations are performed in order from the exhaust units with the frosting level. At that time, when comfort is required, comfort can be maintained by controlling so that the defrosting operations of the plurality of exhaust units are not performed simultaneously.

[0359] Furthermore, when comfort is not important, the temperature control of the plurality of ventilation devices is stopped simultaneously, and the defrosting operations are performed simultaneously by the exhaust units of the plurality of ventilation devices. As a result, since the temperature control is stopped, the comfort level decreases, but the defrosting operation can be performed in a short period.

[0360] In the above-described embodiments and modifications, the air supply unit is a casing (an example of a first casing) that houses at least a part of the first heat exchanger 22 and the air flow path (an example of a first air flow path), and the exhaust unit is a casing (an example of a second casing) that houses at least a part of the second heat exchanger 12 and the air flow path (an example of a second air flow path), and an example in which the casings are separated from each other has been described.

[0361] As a result, it becomes possible to arrange the exhaust unit and the air supply unit at separate positions. Thereby, for a ventilation device capable of recovering heat, the degree of freedom in arrangement can be increased as compared with the prior art.

[0362] However, the above-described embodiments and modifications are not limited to the example in which the casings of the air supply unit and the exhaust unit are separated, and the air supply unit and the exhaust unit may be integrated. That is, when the first heat exchanger 22 and the second heat exchanger 12 are connected by a refrigerant circuit and a fan 21 corresponding to the first heat exchanger 22 and a fan corresponding to the second heat exchanger 12 are provided, the air volume adjustment and the refrigerant temperature adjustment as shown in the above-described embodiments and modifications can be applied. Thus, the methods shown in the above-described embodiments and modifications may be applied even when the air supply unit and the exhaust unit have an integrated configuration.

[0363] The above-described embodiments and modifications illustrate a defrosting method. The methods shown in the above-described embodiments and modifications are not limited to using only the defrosting method, and may be used in combination with one or more defrosting methods shown in other embodiments and modifications.

[0364] Although the embodiments have been described above, it will be understood that various changes in form and detail are possible without departing from the spirit and scope of the claims. Various modifications and improvements such as combinations and substitutions with part or all of other embodiments are possible.

Explanation of Reference Numerals

[0365] 1, 1B, 1C, 1D, 1E, 1F_1, 1F_2, 1F_3 Ventilation device 2, 2B, 2F Air conditioner 10, 110A, 110B, 210, 310, 510A, 510B, 510C Exhaust unit 11 Fan 12 Second heat exchanger 13, 113A, 113B, 213, 313, 413 Control unit 14 Temperature detection unit 15 Driving motor 16 Electric valve 20, 120A, 120B, 220A, 220B, 520A, 520B, 520C Air supply unit 21 Fan 22 First heat exchanger 23, 123, 423 Control unit 24 Temperature detection unit 25 Driving motor 26 Electric valve 240, 440 On-off damper 341 First on-off damper 342 Second on-off damper 50, 150, 550A, 550B, 550C Compressor unit 51 Driving motor 52, 152 Control unit 53 Compressor 54 Four-way valve 55 Electric valve 156 Bypass electric valve 70, 170, 571, 572, 573 Outdoor unit 71, 171 Control unit 81, 82, 581, 582, 583, 584, 585, 586, 587, 588 Air-conditioning indoor unit 100, 500 Upper control device 161, 162 Electric valve F1, F2, F3, F4, F101, F102, F103, F104 Refrigerant circuit F106 Bypass flow path F5, F501, F502, F503 Connecting pipe P1 Air supply flow path P2 return air flow path P101 First air supply flow path P102 Second air supply flow path P103 First exhaust flow path P104 Second exhaust flow path P202 Return air flow path P202A First return air branch path P202B Second return air branch path P402 Bypass flow path P403 Return air flow path

Claims

1. A compressor; a first heat exchanger functioning as a condenser or an evaporator; a first air flow path that supplies air taken in from outdoors to an indoor space after passing the air through the first heat exchanger; a second heat exchanger functioning as a condenser or an evaporator; a second air flow path that exhausts air taken in from the indoor space to the outdoors after passing the air through the second heat exchanger; a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by a refrigerant piping and a refrigerant flows inside; a control unit that outputs a predetermined command to an actuator that controls a state of the refrigerant in the refrigerant circuit so as to raise the temperature of the second heat exchanger and raise the temperature of the refrigerant flowing into the second heat exchanger by guiding an air flow in the indoor space to the second heat exchanger when it is determined that the second heat exchanger is in a frosted state; The control unit further performs control, when receiving a signal from the air conditioner to perform a defrosting operation, to increase the air volume of the air supplied from the first air flow path to the indoor space compared to before receiving the signal from the air conditioner to perform a defrosting operation, and performs control to increase the air volume of the air exhausted from the second air flow path to the outdoors compared to before receiving the signal from the air conditioner to perform a defrosting operation, When it is determined that the second heat exchanger is in a frosted state after receiving a signal indicating that a defrosting operation is to be performed from the air conditioner, the control unit suppresses outputting the predetermined command to an actuator that controls a state of the refrigerant in the refrigerant circuit. Ventilation equipment.

2. a first air flow path for supplying air taken from the indoor space to an indoor space after passing the air through the first heat exchanger; a second air flow path for exhausting the air taken from the indoor space to the outdoor space after passing the air through the second heat exchanger; and a refrigerant circuit in which the compressor, the first heat exchanger, and the second heat exchanger are connected by a refrigerant piping and a refrigerant flows through the inside of the refrigerant circuit, when a control unit controls a ventilation device including: a compressor; a first heat exchanger functioning as a condenser or an evaporator; The control unit further performs control, when receiving a signal from the air conditioner to perform a defrosting operation, to increase the air volume of the air supplied from the first air flow path to the indoor space compared to before receiving the signal from the air conditioner to perform a defrosting operation, and performs control to increase the air volume of the air exhausted from the second air flow path to the outdoors compared to before receiving the signal from the air conditioner to perform a defrosting operation, When it is determined that the second heat exchanger is in a frosted state after receiving a signal indicating that a defrosting operation is to be performed from the air conditioner, the control unit suppresses outputting the predetermined command to an actuator that controls a state of the refrigerant in the refrigerant circuit. Ventilation methods.

Images