WO2023058197A1

WO2023058197A1 - Air conditioner

Info

Publication number: WO2023058197A1
Application number: PCT/JP2021/037196
Authority: WO
Inventors: 貴大橋川
Original assignee: 三菱電機株式会社
Priority date: 2021-10-07
Filing date: 2021-10-07
Publication date: 2023-04-13
Also published as: EP4414622A1; JPWO2023058197A1; CN118019948A

Abstract

An outdoor unit (10) is provided with a compressor (11) and an outdoor heat exchanger (13). An indoor unit (20) is provided with: an expansion valve (26); a supply air heat exchanger (22) and an exhaust heat exchanger (23) that are indoor heat exchangers; a blower (28) serving as an air supply device that brings outdoor air (OA) into a room through a supply air path; and a blower (29) serving as an exhaust device that discharges indoor air (RA) to the outside through an exhaust air path. The indoor heat exchangers are configured so as to allow passage of each of air flowing through the supply air path and air flowing through the exhaust air path. The indoor unit (20) is also provided with a first damper (24) serving as a switching device that can switch whether or not to allow the indoor air (RA) flowing in the exhaust air path to pass through the exhaust heat exchanger (23) that is a indoor heat exchanger.

Description

air conditioner

The present disclosure relates to air conditioners.

One of the methods of air conditioners is the convection air conditioning system, which adjusts the temperature of the air sucked in from the outside and blows it out into the indoor space. In the convection air conditioning system, when low-temperature air is blown into the room during cooling, if the temperature of the blown air is too low, the occupants will feel the cold air and the comfort will decrease. On the other hand, in the convection air-conditioning system, when high-temperature air is blown into the room during heating, if the temperature of the blown-out air is too high, the occupants will feel warm air, which will reduce comfort.

Japanese Patent No. 5054935 (Patent Document 1) discloses a technique for operating an air conditioner with a predetermined lower limit for the temperature of the blown air in order to improve the comfort of the occupants.

Japanese Patent No. 5054935

For example, the air conditioner of Patent Document 1 lowers the frequency of the compressor to raise the evaporation temperature and lowers the opening of the expansion valve when the temperature of the blown air is below a predetermined lower limit during cooling operation. By increasing the degree of superheat at the outlet of the evaporator, the cooling capacity is suppressed and the drop in temperature of the blown air is prevented. However, in the air conditioner of Patent Literature 1, the cooling capacity may not be fully throttled due to limitations in the operating range such as the frequency of the compressor reaching the lower limit, and the temperature of the blown air may fall below the set value. Alternatively, in the air conditioner of Patent Literature 1, the temperature of the blown air may not be stabilized by avoiding a drop in the temperature of the blown air by stopping cooling.

An object of the present disclosure is to provide an air conditioner capable of maintaining a suitable temperature of blown air while executing continuous operation.

The present disclosure relates to an air conditioner that includes an outdoor unit and an indoor unit. The outdoor unit and the indoor unit are connected by refrigerant pipes to form a refrigerant circuit. The outdoor unit includes a compressor and an outdoor heat exchanger. The indoor unit includes an expansion valve, an indoor heat exchanger, an air supply device that takes in outdoor air into the room through a supply air passage, and an exhaust device that discharges the indoor air to the outside through an exhaust air passage. The indoor heat exchanger is configured to allow passage of air flowing through the supply air passage and air flowing through the exhaust air passage. The indoor unit further includes a switching device capable of switching whether the indoor air flowing through the exhaust air passage passes through the indoor heat exchanger.

According to the air conditioner of the present disclosure, it is possible to maintain a suitable temperature of the blown air while executing continuous operation.

1 is a schematic diagram showing the configuration of an air conditioner according to Embodiment 1. FIG. 1 is a schematic diagram showing the configuration of an indoor unit according to Embodiment 1. FIG. 2 is a refrigerant circuit diagram of the air conditioner according to Embodiment 1. FIG. 4 is a flowchart showing damper control during cooling operation in Embodiment 1. FIG. FIG. 4 is a diagram showing an example of damper operation in Embodiment 1; FIG. FIG. 4 is a diagram showing an example of damper operation in Embodiment 1; FIG. FIG. 4 is a diagram showing an example of damper operation in Embodiment 1; FIG. FIG. 4 is a refrigerant state transition diagram according to Embodiment 1; 4 is a flowchart showing damper control during heating operation in Embodiment 1. FIG. 4 is a schematic diagram showing the configuration of an indoor unit according to Embodiment 2. FIG. 9 is a flowchart showing damper control during cooling operation in Embodiment 2. FIG. FIG. 11 is a schematic diagram showing the configuration of an indoor unit according to Embodiment 3; 10 is a flow chart showing damper control during cooling operation in Embodiment 3. FIG. FIG. 12 is a diagram showing an example of damper operation in Embodiment 3; FIG. 12 is a diagram showing an example of damper operation in Embodiment 3; FIG. 12 is a diagram showing an example of damper operation in Embodiment 3; FIG. 11 is a schematic diagram showing the configuration of an indoor unit in a modified example of Embodiment 3; FIG. 11 is a schematic diagram showing the configuration of an indoor unit according to Embodiment 4; 14 is a flow chart showing damper control during heating operation in Embodiment 4. FIG.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, when referring to the number, amount, etc., the scope of the present disclosure is not necessarily limited to the number, amount, etc., unless otherwise specified. The same reference numbers are given to the same parts and equivalent parts, and redundant description may not be repeated. It is planned from the beginning to use the configurations in the embodiments in combination as appropriate.

Embodiment 1.
<Configuration>
1 to 3, the configuration of the air conditioner 100 according to Embodiment 1, the configuration of the indoor unit 20 of the air conditioner 100 according to Embodiment 1, and the refrigerant circuit of the air conditioner 100 according to Embodiment 1. will be described.

FIG. 1 is a schematic diagram showing the configuration of an air conditioner 100 according to Embodiment 1, FIG. 2 is a schematic diagram showing the configuration of an indoor unit 20 according to Embodiment 1, and FIG. 1 is a refrigerant circuit diagram of the air conditioner 100 in FIG.

The air conditioner 100 includes an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 and the indoor unit 20 are connected by refrigerant piping 30 . The indoor unit 20 which is an outside air processing unit is arranged in the ceiling space 101 . The indoor unit 20 takes in the outdoor air OA and blows it out from the duct 40 as supply air SA through the outlet 41 . The indoor unit 20 takes in the indoor air RA into the duct 40 through the suction port 42 and discharges it to the outside as the exhaust air EA.

The indoor unit 20 includes a total heat exchanger 21, a supply air heat exchanger 22, an exhaust heat exchanger 23, a supply air blower 28, an exhaust air blower 29, a supply air temperature A detection unit 50 and an outside air temperature detection unit 51 are included. FIG. 1 shows a schematic diagram of the indoor unit 20 viewed from the side. FIG. 2 shows a schematic diagram of the indoor unit 20 viewed from above.

The total heat exchanger 21 has, for example, a structure in which a plurality of crossing ventilation paths are alternately stacked. In the total heat exchanger 21, total heat exchange is performed between the indoor air RA and the outdoor air OA as the indoor air RA and the outdoor air OA pass through the ventilation path. In total heat exchange, not only sensible heat (temperature) but also latent heat (water vapor) is exchanged.

The supply air heat exchanger 22 and the exhaust heat exchanger 23 are indoor heat exchangers that exchange heat between refrigerant and air. The supply air temperature detector 50 is a device for measuring the temperature of the supply air SA blown into the room. The outdoor air temperature detection unit 51 is a device for measuring the temperature of the outdoor air OA taken into the room from the outdoors.

The outdoor air OA is led to the total heat exchanger 21 by a blower 28 as an air supply device, and after passing through the supply air heat exchanger 22, is supplied indoors as supply air SA. An air passage through which the outdoor air OA flows into the room is called a supply air passage. On the other hand, the room air RA is discharged to the outside as the exhaust EA by the blower 29 as an exhaust device. An air passage through which the indoor air RA flows to the outside is called an exhaust air passage.

As shown in FIG. 2, a first damper 24 and a second damper 25 as switching devices for switching the flow of air indicated by various arrows are arranged in the exhaust air passage. The first damper 24 can switch whether the room air RA flowing through the exhaust air passage passes through the exhaust heat exchanger 23 or not. The second damper 25 can switch whether the room air RA flowing through the exhaust air passage passes through the total heat exchanger 21 or not.

By switching the first damper 24 and the second damper 25, the indoor air RA, for example, passes through the total heat exchanger 21 without passing through the exhaust heat exchanger 23, the exhaust heat exchanger 23 and the total heat exchanger 21 or a pattern that passes through the exhaust heat exchanger 23 and does not pass through the total heat exchanger 21.

As shown in FIG. 3, in the air conditioner 100, the outdoor unit 10 and the indoor unit 20 are connected by

refrigerant pipes

30a and 30b. The outdoor unit 10 includes a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, and a blower 14 as an outdoor unit fan. The indoor unit 20 includes a supply air heat exchanger 22 , an exhaust heat exchanger 23 and an expansion valve 26 .

The air conditioner 100 circulates the refrigerant in the order of the compressor 11, the outdoor heat exchanger 13, the expansion valve 26, the exhaust heat exchanger 23, and the supply air heat exchanger 22 during cooling operation. The air conditioner 100 circulates the refrigerant in order of the compressor 11, the supply air heat exchanger 22, the exhaust heat exchanger 23, the expansion valve 26, and the outdoor heat exchanger 13 during the heating operation.

The compressor 11 sucks and compresses the low-temperature, low-pressure refrigerant and discharges it as a high-temperature, high-pressure gas refrigerant. The compressor 11 is driven by, for example, an inverter, and its capacity (amount of refrigerant discharged per unit time) is controlled. The four-way valve 12 switches the refrigerant flow according to the operating mode of the air conditioner 100 .

The outdoor heat exchanger 13 exchanges heat between the refrigerant flowing through the refrigerant circuit and the outdoor air. A blower 14 is adjacent to the outdoor heat exchanger 13 . Air blower 14 blows air to outdoor heat exchanger 13 . The expansion valve 26 is, for example, an electronic expansion valve whose opening degree can be controlled. The air conditioner 100 includes a control device 60 that centrally controls drive components such as the blower 14 and the expansion valve 26 .

The control device 60 includes a CPU (Central Processing Unit) 61, a memory 62 (ROM (Read Only Memory) and RAM (Random Access Memory)), and input/output devices (not shown) for inputting and outputting various signals. Configured. The CPU 61 expands the program stored in the ROM into the RAM or the like and executes it. The program stored in the ROM is a program in which processing procedures of the control device 60 are described. The control device 60 controls each device according to these programs. This control is not limited to processing by software, and processing by dedicated hardware (electronic circuit) is also possible.

The control device 60 adjusts the amount of air blown, for example, by controlling the rotational speeds of the

fans

14, 28, and 29. The control device 60 controls the amount of pressure reduction of the refrigerant, for example, by controlling the degree of opening of the expansion valve 26 .

<Action>
FIG. 4 is a flowchart showing damper control during cooling operation in the first embodiment. 5 to 7 are diagrams showing an example of damper operation according to Embodiment 1. FIG.

As shown in FIG. 4, in step S1, the control device 60 determines whether or not the supply air temperature _TSA detected by the supply air temperature detection unit 50 is higher than a preset lower limit air temperature _TL . do. The lower limit air temperature _TL is a temperature set as a temperature at which cool air is felt by indoor residents. If the supply air temperature _TSA is higher than the lower limit air temperature _TL (YES in step S1), that is, if there is no need to suppress the cooling capacity, the controller 60 proceeds to the process of step S2.

In step S2, the controller 60 controls the first damper 24 so that the room air RA does not pass through the exhaust heat exchanger 23, as shown in FIGS. Next, the controller 60 compares the indoor air temperature _TIN with the outdoor air temperature _TOA (step S3). The indoor air temperature _TIN is measured by a thermometer (not shown) placed in the indoor space. The outdoor air temperature _TOA is measured by the outdoor air temperature detector 51 .

When the indoor air temperature _TIN is lower than the outdoor air temperature _TOA (YES in step S3), the controller 60 proceeds to the process of step S4. In step S4, the controller 60 controls the second damper 25 so that the indoor air RA passes through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG. As a result, total heat exchange is performed between the indoor air RA and the outdoor air OA in the total heat exchanger 21, so that the outdoor air OA passing through the supply air passage can be cooled.

If the indoor air temperature _TIN is higher than the outdoor air temperature _TOA (NO in step S3), the controller 60 proceeds to step S5. In step S5, the controller 60 controls the second damper 25 so that the room air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG. As a result, when it is not necessary to cool the outdoor air OA passing through the supply air passage, the total heat exchange is prevented between the indoor air RA and the outdoor air OA in the total heat exchanger 21. can be done.

If the supply air temperature _TSA is lower than the lower limit air temperature _TL in step S1 (NO in step S1), that is, if it is necessary to suppress the cooling capacity, the controller 60 proceeds to step S6. . In step S6, the controller 60 controls the first damper 24 so that the indoor air RA passes through the exhaust heat exchanger 23, as shown in FIG. Next, in step S7, the control device 60 controls the second damper 25 so that the indoor air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG.

By the process of step S6, the room air RA flowing through the exhaust air passage passes through the exhaust heat exchanger 23, thereby cooling the room air RA. As a result, the cooling capacity of the supply air heat exchanger 22 can be suppressed and the supply air temperature _TSA can be raised. By the process of step S7, it is possible to prevent the indoor air RA from passing through the total heat exchanger 21 and to prevent the outdoor air OA passing through the supply air passage from being cooled. Therefore, it is possible to reduce the minimum capacity (exchange heat amount of the supply air SA) when the cooling capacity is suppressed, and to widen the supply air temperature range in which continuous operation is possible.

FIG. 8 is a refrigerant state transition diagram according to the first embodiment. The vertical axis indicates the pressure p and the horizontal axis indicates the specific enthalpy h. As indicated by the line connecting point A to point E on the ph diagram, the refrigeration cycle is described when the indoor unit 20 acts as an evaporator. In FIG. 8, points A to C are evaporation processes performed in the indoor unit 20, points C to D are condensation processes performed in the compressor 11, and points D to E are condensation processes performed in the outdoor unit. , point E to point A indicate the expansion stroke performed in the expansion valve 26 .

As shown in FIG. 8, in the evaporation process, air is caused to flow from point A to point B in the exhaust heat exchanger 23, thereby exchanging heat in the exhaust heat exchanger 23 for the amount of heat exchanged _QEA . As a result, the specific enthalpy of the refrigerant flowing into the supply air heat exchanger 22 is increased from h1 to h2. In the evaporation process, air is flown from point B to point C into the supply air heat exchanger 22, so that the supply air heat exchanger 22 exchanges the heat amount corresponding to the exchange heat amount _QSA .

Thus, in the evaporation process, the specific enthalpy of the refrigerant is increased from h1 to h2 in the exhaust heat exchanger 23, and the specific enthalpy of the refrigerant is increased from h2 to h3 in the supply air heat exchanger 22. For this reason, compared with the case where the air does not pass through the exhaust heat exchanger 23, the exchange heat quantity _QSA of the supply air heat exchanger 22 can be reduced. Thereby, the decrease in the temperature of the supply air SA can be suppressed.

FIG. 9 is a flowchart showing damper control during heating operation according to the first embodiment. As shown in FIG. 9, in step S11, the control device 60 determines whether or not the supply air temperature _TSA detected by the supply air temperature detection unit 50 is lower than the preset upper limit air temperature _TH . do. The upper limit air temperature T _H is a temperature set as a temperature at which warm air can be felt by the occupants of the room. If the supply air temperature _TSA is lower than the upper limit air temperature _TH (YES in step S11), that is, if the heating capacity does not need to be suppressed, the control device 60 proceeds to the process of step S12.

The control device 60 controls the first damper 24 so that the indoor air RA does not pass through the exhaust heat exchanger 23 in step S12. Next, the controller 60 compares the indoor air temperature _TIN with the outdoor air temperature _TOA (step S13). The indoor air temperature _TIN is measured by a thermometer (not shown) placed in the indoor space. The outdoor air temperature _TOA is measured by the outdoor air temperature detector 51 .

When the indoor air temperature _TIN is higher than the outdoor air temperature _TOA (YES in step S13), the control device 60 proceeds to the process of step S14. In step S14, the controller 60 controls the second damper 25 so that the indoor air RA passes through the total heat exchanger 21, and returns the process from the subroutine to the main routine. As a result, total heat exchange is performed between the indoor air RA and the outdoor air OA in the total heat exchanger 21, so that the outdoor air OA passing through the supply air passage can be heated.

When the indoor air temperature _TIN is lower than the outdoor air temperature _TOA (NO in step S13), the control device 60 proceeds to the process of step S15. In step S15, the controller 60 controls the second damper 25 so that the indoor air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine. As a result, when it is not necessary to heat the outdoor air OA passing through the supply air passage, the total heat exchange between the indoor air RA and the outdoor air OA is not performed in the total heat exchanger 21. can be done.

If the supply air temperature _TSA is higher than the upper limit air temperature _TH in step S11 (NO in step S11), that is, if the heating capacity needs to be suppressed, the control device 60 proceeds to the process of step S16. . The controller 60 controls the first damper 24 so that the indoor air RA passes through the exhaust heat exchanger 23 in step S16. Next, in step S17, the controller 60 controls the second damper 25 so that the indoor air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine.

By the process of step S16, the room air RA flowing through the exhaust air passage passes through the exhaust heat exchanger 23, thereby heating the room air RA. As a result, the heating capacity of the supply air heat exchanger 22 can be suppressed, and the supply air temperature _TSA can be lowered. By the process of step S17, it is possible to prevent the indoor air RA from passing through the total heat exchanger 21 and prevent the outdoor air OA passing through the supply air passage from being heated.

Embodiment 2.
<Configuration>
FIG. 10 is a schematic diagram showing the configuration of the indoor unit 20A according to the second embodiment. The configuration of the second embodiment is the same as that of the indoor unit 20 of the first embodiment except that the first damper 24 has a mechanism for adjusting the angle. The control device 60 changes the angle of the first damper 24 depending on the situation.

<Action>
FIG. 11 is a flow chart showing damper control in the second embodiment. Referring to FIG. 11, damper control will be described by taking control during cooling operation as an example.

As shown in FIG. 11, in step S21, the controller 60 determines whether or not the supply air temperature _TSA detected by the supply air temperature detector 50 is higher than a preset target value air temperature _TT . do. The target value air temperature _TT is a set temperature that the indoor occupants feel is appropriate.

If the supply air temperature _TSA is higher than the target value air temperature _TT (YES in step S21), that is, if the supply air temperature _TSA is desired to be lowered, the process proceeds to step S22. In step S22, control device 60 performs control to change the angle of first damper 24 so that the amount of indoor air RA passing through exhaust heat exchanger 23 is reduced. As a result, the amount of air passing through the exhaust heat exchanger 23 is reduced, and the amount of heat exchanged in the supply air heat exchanger 22 can be increased. Due to the increase in the amount of heat exchanged in the supply air heat exchanger 22, the supply air temperature _TSA can be lowered.

If the supply air temperature _TSA is lower than the target value air temperature _TT (NO in step S21), that is, if it is desired to raise the supply air temperature _TSA , the control device 60 proceeds to the process of step S23. In step S<b>23 , the control device 60 performs control to change the angle of the first damper 24 so as to increase the air volume of the indoor air RA passing through the exhaust heat exchanger 23 . As a result, the amount of air passing through the exhaust heat exchanger 23 increases, and the amount of heat exchanged in the supply air heat exchanger 22 can be reduced. Due to the reduction in the amount of heat exchanged in the charge air heat exchanger 22, the charge air temperature _TSA can be increased.

Thus, according to the indoor unit 20A in Embodiment 2, when the supply air temperature _TSA is desired to approach the target value air temperature _TT , the supply air heat The amount of heat exchanged by the exchanger 22 can be controlled.

Embodiment 3.
<Configuration>
FIG. 12 is a schematic diagram showing the configuration of an indoor unit 20B according to Embodiment 3. As shown in FIG. Embodiment 3 differs from Embodiment 1 in that supply air heat exchanger 22 is downsized and exhaust heat exchanger 23 is arranged adjacent to supply air heat exchanger 22 . As shown in FIG. 12, in the indoor unit 20B, the supply air heat exchanger 22 is downsized, and the exhaust heat exchanger 23 is arranged adjacent to the supply air heat exchanger 22, so that the entire heat exchanger can be reduced in size.

The indoor unit 20B in Embodiment 3 is equipped with a first damper group for switching whether the indoor air RA or the outdoor air OA passes through the exhaust heat exchanger 23 instead of the first damper 24. The configuration is different from that of form 1. The first damper group includes a third damper 24a, a fourth damper 24b, and a fifth damper 24c. In the indoor unit 20B, the supply air heat exchanger 22 is located in the supply air path, and the exhaust heat exchanger 23 is controlled by the control device 60 controlling the third damper 24a, the fourth damper 24b, and the fifth damper 24c. It is located in a common air path that is switched to allow either one of the outdoor air OA and the indoor air RA to pass through. The control device 60 switches whether the indoor air RA or the outdoor air OA passes through the exhaust heat exchanger 23 by changing the positions of the third damper 24a, the fourth damper 24b, and the fifth damper 24c.

<Action>
FIG. 13 is a flow chart showing damper control in the third embodiment. 14 to 16 are diagrams showing an example of damper operation according to the third embodiment. Referring to FIG. 13, damper control will be described using control during cooling operation as an example.

As shown in FIG. 13, in step S31, the control device 60 determines whether or not the supply air temperature _TSA detected by the supply air temperature detection unit 50 is higher than a preset lower limit air temperature _TL . do. The lower limit air temperature _TL is a temperature set as a temperature at which cool air is felt by indoor residents. If supply air temperature _TSA is higher than lower limit air temperature _TL (YES in step S31), that is, if there is no need to suppress the cooling capacity, control device 60 proceeds to the process of step S32.

In step S32, the control device 60 controls the third damper 24a, the fourth damper 24b, and the fifth damper 24c so that the indoor air RA does not pass through the exhaust heat exchanger 23, as shown in FIGS. . In step S32, the control device 60 controls the third damper 24a, the fourth damper 24b, and the fifth damper 24c so that the outdoor air OA passes through the exhaust heat exchanger 23, as shown in FIGS. .

Next, the controller 60 compares the indoor air temperature _TIN with the outdoor air temperature _TOA (step S33). The indoor air temperature _TIN is measured by a thermometer (not shown) placed in the indoor space. The outdoor air temperature _TOA is measured by the outdoor air temperature detector 51 .

When the indoor air temperature _TIN is lower than the outdoor air temperature _TOA (YES in step S33), the controller 60 proceeds to the process of step S34. In step S34, the controller 60 controls the second damper 25 so that the indoor air RA passes through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG. As a result, total heat exchange is performed between the indoor air RA and the outdoor air OA in the total heat exchanger 21, so that the outdoor air OA passing through the supply air passage can be cooled.

By the processing in steps S32 and S34, the first damper group (third damper 24a, fourth damper 24b, fifth damper 24c) and second damper 25 are switched to the arrangement shown in FIG. As shown in FIG. 14, the outdoor air OA passes through the total heat exchanger 21 by the blower 28, passes through the supply air heat exchanger 22 and the exhaust heat exchanger 23, and is supplied indoors as supply air SA. . The indoor air RA passes through the total heat exchanger 21 by the blower 29 and is exhausted to the outside as the exhaust EA.

As a result, when it is not necessary to suppress the cooling capacity, it is possible to prevent the cooling capacity of the indoor unit 20B from being lowered by preventing the indoor air RA from passing through the exhaust heat exchanger 23. In the indoor unit 20B, since the outdoor air OA passes through the exhaust heat exchanger 23 together with the supply air heat exchanger 22, the cooling capacity can be improved. In the indoor unit 20B, total heat exchange is performed between the indoor air RA and the outdoor air OA in the total heat exchanger 21, so that the outdoor air OA passing through the supply air passage can be cooled.

When the indoor air temperature _TIN is higher than the outdoor air temperature _TOA (NO in step S33), the controller 60 proceeds to the process of step S35. In step S35, the controller 60 controls the second damper 25 so that the indoor air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG. As a result, when it is not necessary to cool the outdoor air OA passing through the supply air passage, the total heat exchange is prevented between the indoor air RA and the outdoor air OA in the total heat exchanger 21. can be done.

By the processing in steps S32 and S35, the first damper group (third damper 24a, fourth damper 24b, fifth damper 24c) and second damper 25 are switched to the arrangement shown in FIG. As shown in FIG. 15, the outdoor air OA passes through the total heat exchanger 21 by the blower 28, passes through the supply air heat exchanger 22 and the exhaust heat exchanger 23, and is supplied indoors as supply air SA. . The indoor air RA is exhausted to the outside as exhaust EA by the blower 29 without passing through the total heat exchanger 21 .

As a result, when it is not necessary to suppress the cooling capacity, it is possible to prevent the cooling capacity of the indoor unit 20B from being lowered by preventing the indoor air RA from passing through the exhaust heat exchanger 23. In the indoor unit 20B, since the outdoor air OA passes through the exhaust heat exchanger 23 together with the supply air heat exchanger 22, the cooling capacity can be improved. In the indoor unit 20B, the indoor air RA can be prevented from passing through the total heat exchanger 21 and can be prevented from exchanging heat with the outdoor air OA passing through the supply air passage.

If the supply air temperature _TSA is lower than the lower limit air temperature _TL in step S31 (NO in step S31), that is, if the cooling capacity needs to be suppressed, the control device 60 proceeds to the process of step S36. . In step S36, the controller 60 controls the third damper 24a, the fourth damper 24b, and the fifth damper 24c so that the indoor air RA passes through the exhaust heat exchanger 23, as shown in FIG. Next, in step S37, the controller 60 controls the second damper 25 so that the indoor air RA does not pass through the total heat exchanger 21, and returns the process from the subroutine to the main routine, as shown in FIG.

By the process of step S36, the room air RA flowing through the exhaust air passage passes through the exhaust heat exchanger 23, thereby cooling the room air RA. As a result, the cooling capacity of the supply air heat exchanger 22 can be suppressed and the supply air temperature _TSA can be raised. By the process of step S37, it is possible to prevent the indoor air RA from passing through the total heat exchanger 21 and to prevent the outdoor air OA passing through the supply air passage from being cooled. Therefore, it is possible to reduce the minimum capacity (exchange heat amount of the supply air SA) when the cooling capacity is suppressed, and to widen the supply air temperature range in which continuous operation is possible.

In the indoor unit 20B of Embodiment 3, when the supply air temperature _TSA does not fall below the lower limit air temperature _TL , the exhaust heat exchanger 23 is used to cool the outdoor air OA as shown in FIGS. can be done. Therefore, the size and specifications of the supply air heat exchanger 22 can be reduced, and the cost of the product can be suppressed.

<Configuration>
FIG. 17 is a schematic diagram showing the configuration of an indoor unit 20C in a modified example of the third embodiment. The modification of the third embodiment differs from the third embodiment in that part of the supply air heat exchanger 22 also serves as the exhaust heat exchanger 23 of the third embodiment. Other points are the same as those of the third embodiment.

The air passage of the indoor unit 20C is divided by a third damper 24a, a fourth damper 24b, and a fifth damper 24c. In the indoor unit 20C, part of the supply air heat exchanger 22 can have the function of the exhaust heat exchanger 23 shown in the third embodiment by partitioning the air passage.

Embodiment 4.
<Configuration>
FIG. 18 is a schematic diagram showing the configuration of an indoor unit 20D according to the fourth embodiment. The configuration of the indoor unit 20D in the fourth embodiment is the same as the configuration of the indoor unit 20 in the first embodiment. In the fourth embodiment, control when the outdoor air temperature _TOA is lower than the preset freezing temperature _Tf during heating operation will be described. The freezing temperature _Tf is a temperature set as a temperature at which moisture in the air flowing through the exhaust air passage may freeze.

When the outdoor air temperature _TOA is lower than the freezing temperature _Tf , the indoor air RA flowing through the exhaust air passage is cooled by the outdoor air OA, and the moisture contained in the air may freeze. As a result, there is a problem that the total heat exchanger 21 is clogged.

<Action>
FIG. 19 is a flow chart showing damper control in the fourth embodiment. In FIG. 19, the control of the damper will be described using the control during the heating operation as an example. In the indoor unit 20D, the supply air heat exchanger 22 and the exhaust heat exchanger 23 act as condensers.

As shown in FIG. 19, in step S41, the controller 60 determines whether the outdoor air temperature _TOA is higher than the freezing temperature _Tf . When the outdoor air temperature _TOA is higher than the freezing temperature _Tf (YES in step S41), the controller 60 proceeds to the process of step S42. In the processing of step S42, the control device 60 executes the processing of steps S11 to S17 in FIG. 9 described above, and returns the processing from the subroutine to the main routine.

When the outdoor air temperature _TOA is lower than the freezing temperature _Tf (NO in step S41), the control device 60 proceeds to the process of step S43. The control device 60 controls the first damper 24 so that the indoor air RA passes through the exhaust heat exchanger 23 in the process of step S43. Next, in step S44, the control device 60 controls the second damper 25 so that the indoor air RA passes through the total heat exchanger 21, and returns the process from the subroutine to the main routine.

Thus, according to the indoor unit 20D in Embodiment 4, the temperature of the indoor air RA flowing into the total heat exchanger 21 can be increased by passing through the exhaust heat exchanger 23 (steps S43, S44 processing). As a result, freezing of moisture in the air in the exhaust air passage and clogging of the total heat exchanger 21 can be reduced.

<Summary>
The present disclosure relates to an air conditioner 100 including an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 and the indoor unit 20 are connected by a refrigerant pipe 30 to form a refrigerant circuit. The outdoor unit 10 includes a compressor 11 and an outdoor heat exchanger 13. The indoor unit 20 includes an expansion valve 26, a supply air heat exchanger 22 and an exhaust heat exchanger 23, which are indoor heat exchangers, and a blower 28 as an air supply device that takes in the outdoor air OA into the room through the supply air passage. and a blower 29 as an exhaust device for discharging indoor air RA to the outside through an exhaust air passage. The indoor heat exchanger is configured to allow passage of air flowing through the supply air passage and air flowing through the exhaust air passage. The indoor unit 20 further includes a first damper 24 as a switching device capable of switching whether the indoor air RA flowing through the exhaust air passage passes through the exhaust heat exchanger 23, which is an indoor heat exchanger.

Preferably, the indoor heat exchanger comprises a supply air heat exchanger 22 as a first indoor heat exchanger and an exhaust air heat exchanger 23 as a second indoor heat exchanger. The indoor unit 20 further includes a control device 60 that controls the operation of the first damper 24 . The controller 60 controls the first damper 24 so that the room air RA passes through the exhaust heat exchanger 23, thereby suppressing the amount of heat exchanged by the supply air heat exchanger 22 in the supply air passage.

Preferably, the indoor heat exchanger comprises a supply air heat exchanger 22 as a first indoor heat exchanger and an exhaust air heat exchanger 23 as a second indoor heat exchanger. The indoor unit 20 further includes a control device 60 that controls the operation of the first damper 24 . The first damper 24 can adjust the air volume of the indoor air RA passing through the exhaust heat exchanger 23 . The control device 60 adjusts the amount of heat exchanged by the supply air heat exchanger 22 in the supply air path by controlling the first damper 24 so as to adjust the air volume of the indoor air RA passing through the exhaust heat exchanger 23 .

Preferably, the indoor heat exchanger comprises a supply air heat exchanger 22 as a first indoor heat exchanger and an exhaust air heat exchanger 23 as a second indoor heat exchanger. The indoor unit 20 further includes a control device 60 that controls operations of the third damper 24a, the fourth damper 24b, and the fifth damper 24c as switching devices. The supply air heat exchanger 22 is positioned in the supply air path, and the control device 60 controls the third damper 24a, the fourth damper 24b, and the fifth damper 24c to control the outdoor air OA and the indoor air OA. It is located in a common air path that can be switched to pass either one of the air RA and the air RA.

Preferably, the indoor unit 20 further includes a total heat exchanger 21 that exchanges heat between the outdoor air OA and the indoor air RA. The second damper 25 as a switching device can switch whether the room air RA flowing through the exhaust air passage passes through the total heat exchanger 21 or not.

Preferably, the switching device includes a first damper 24 for switching whether or not the room air RA passes through the exhaust heat exchanger 23, and a second damper 24 for switching whether or not the room air RA passes through the total heat exchanger 21. 25. When the temperature _TSA of the supply air taken into the room is higher than the preset lower limit and the indoor air temperature _TIN is lower than the outdoor air temperature _TOA , the controller 60 controls the indoor air RA to exhaust heat exchange. The first damper 24 is controlled so that the indoor air RA does not pass through the heat exchanger 23 , and the second damper 25 is controlled so that the room air RA passes through the total heat exchanger 21 .

Preferably, the switching device includes a first damper 24 for switching whether or not the room air RA passes through the exhaust heat exchanger 23, and a second damper 24 for switching whether or not the room air RA passes through the total heat exchanger 21. 25. When the temperature _TSA of the supply air taken into the room is higher than the preset lower limit and the indoor air temperature _TIN is higher than the outdoor air temperature _TOA , the controller 60 controls the indoor air RA to exhaust heat exchange. The first damper 24 is controlled so that the indoor air RA does not pass through the heat exchanger 23, and the second damper 25 is controlled so that the indoor air RA does not pass through the total heat exchanger 21.

Preferably, the switching device includes a first damper 24 for switching whether or not the room air RA passes through the exhaust heat exchanger 23, and a second damper 24 for switching whether or not the room air RA passes through the total heat exchanger 21. 25. The control device 60 controls the first damper 24 so that the indoor air RA passes through the exhaust heat exchanger 23 when the temperature _TSA of the supply air taken into the room is lower than a preset lower limit value. The second damper 25 is controlled so that the air RA does not pass through the total heat exchanger 21.

Preferably, the switching device includes a first damper 24 capable of increasing or decreasing the volume of the room air RA passing through the exhaust heat exchanger 23, and a second damper switching whether or not the room air RA passes through the total heat exchanger 21. 25. When the temperature _TSA of the supply air taken into the room is higher than a preset target value, the control device 60 operates the first damper 24 so that the amount of indoor air RA passing through the exhaust heat exchanger 23 is reduced. When the supply air temperature _TSA is lower than a preset target value, the first damper 24 is controlled so that the amount of room air RA passing through the exhaust heat exchanger 23 increases.

Preferably, the switching device includes a third damper 24a, a fourth damper 24b, and a fifth damper 24c as a first damper group for switching whether the indoor air RA or the outdoor air OA passes through the exhaust heat exchanger 23; A second damper 25 is provided for switching whether the room air RA passes through the total heat exchanger 21 . When the temperature _TSA of the supply air taken into the room is higher than the preset lower limit and the indoor air temperature _TIN is lower than the outdoor air temperature _TOA , the controller 60 controls the outdoor air OA to exhaust heat exchange. The third damper 24a, the fourth damper 24b, and the fifth damper 24c are controlled so that the indoor air RA passes through the heat exchanger 23, and the second damper 25 is controlled so that the indoor air RA passes through the total heat exchanger 21.

Preferably, the switching device includes a third damper 24a, a fourth damper 24b, and a fifth damper 24c as a first damper group for switching whether the indoor air RA or the outdoor air OA passes through the exhaust heat exchanger 23; A second damper 25 is provided for switching whether the room air RA passes through the total heat exchanger 21 . When the temperature _TSA of the supply air taken into the room is higher than the preset lower limit and the indoor air temperature _TIN is higher than the outdoor air temperature _TOA , the controller 60 controls the outdoor air OA to exhaust heat exchange. The third damper 24a, the fourth damper 24b, and the fifth damper 24c are controlled so that the indoor air RA passes through the heat exchanger 23, and the second damper 25 is controlled so that the room air RA does not pass through the total heat exchanger 21.

Preferably, the switching device includes a third damper 24a, a fourth damper 24b, and a fifth damper 24c as a first damper group for switching whether the indoor air RA or the outdoor air OA passes through the exhaust heat exchanger 23; A second damper 25 is provided for switching whether the room air RA passes through the total heat exchanger 21 . The control device 60 controls the third damper 24a and the fourth damper 24b so that the indoor air RA passes through the exhaust heat exchanger 23 when the temperature _TSA of the supply air taken into the room is lower than a preset lower limit value. , controls the fifth damper 24 c and controls the second damper 25 so that the room air RA does not pass through the total heat exchanger 21 .

Preferably, the switching device includes a first damper 24 for switching whether or not the room air RA passes through the exhaust heat exchanger 23, and a second damper 24 for switching whether or not the room air RA passes through the total heat exchanger 21. 25. The control device 60 controls the first damper 24 so that the indoor air RA passes through the first exhaust heat exchanger 23 when the outdoor air temperature _TOA is lower than the freezing temperature _Tf , and the indoor air RA is completely heat exchanged. The second damper 25 is controlled to pass through the vessel 21 .

With the above configuration, the air conditioner 100 of the present embodiment can keep the temperature of the blown air at a suitable level while executing continuous operation.

<Modification>
In the above-described embodiment, the configuration may be such that the total heat exchanger 21 and the second damper 25 are eliminated.

As a method of suppressing the cooling capacity, there is a method of lowering the frequency of the compressor 11 (reducing the rotational speed) to raise the evaporating temperature, and a method of lowering the opening of the expansion valve 26 to raise the degree of superheat at the outlet of the evaporator. In the above-described embodiment, when the supply air temperature _TSA is lower than the lower limit air temperature _TL , the cooling capacity may be suppressed by combining these methods with the damper operation control method described above.

Specifically, when the supply air temperature _TSA is lower than the lower limit air temperature _TL , the control device 60 executes a process of decreasing the frequency of the compressor 11 or a process of decreasing the degree of opening of the expansion valve 26 . Even if the frequency of the compressor 11 is lowered to the lower limit or the opening of the expansion valve 26 is lowered to the lower limit, if the supply air temperature _TSA is lower than the lower limit air temperature _TL , the control device 60 controls the exhaust heat A process for causing air to flow through the exchanger 23 is executed. As a result, the room air RA flowing through the exhaust air passage is cooled, and the cooling capacity of the supply air heat exchanger 22 is suppressed, so that the supply air temperature _TSA can be increased.

Here, the process of lowering the frequency of the compressor 11 or the process of lowering the degree of opening of the expansion valve 26 leads to a decrease in the power consumption of the air conditioner 100 as well as a decrease in the cooling capacity. On the other hand, damper control in the exhaust heat exchanger 23 reduces the cooling capacity of the supply air heat exchanger 22, but the exhaust heat exchanger 23 exhibits the reduced cooling capacity, so the power consumption of the air conditioner 100 is reduced. does not lead to decline. Therefore, power consumption can be suppressed by executing damper control in the exhaust heat exchanger 23 after executing the process of lowering the frequency of the compressor 11 or the process of lowering the degree of opening of the expansion valve 26 .

The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is indicated by the scope of the claims rather than the description of the above-described embodiments, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

10 outdoor unit, 11 compressor, 12 four-way valve, 13 outdoor heat exchanger, 14, 28, 29 blower, 20, 20A, 20B, 20C, 20D indoor unit, 21 total heat exchanger, 22 supply air heat exchanger, 23 exhaust heat exchanger, 24 first damper, 24a third damper, 24b fourth damper, 24c fifth damper, 25 second damper, 26 expansion valve, 30, 30a, 30b refrigerant pipe, 40 duct, 41 outlet, 42 Suction port, 50 Supply air temperature detection part, 51 Outside air temperature detection part, 60 Control device, 61 CPU, 62 Memory, 100 Air conditioner, EA Exhaust air, SA Supply air, OA Outdoor air, RA Indoor air.

Claims

An air conditioner comprising an outdoor unit and an indoor unit,
The outdoor unit and the indoor unit are connected by refrigerant pipes to form a refrigerant circuit,
The outdoor unit includes a compressor and an outdoor heat exchanger,
The indoor unit includes an expansion valve, an indoor heat exchanger, an air supply device that takes in outdoor air into the room through a supply air passage, and an exhaust device that discharges indoor air to the outside through an exhaust air passage,
The indoor heat exchanger is configured to allow passage of air flowing through the supply air passage and air flowing through the exhaust air passage,
The indoor unit further includes a switching device capable of switching whether the indoor air flowing through the exhaust air passage passes through the indoor heat exchanger.
The indoor heat exchanger comprises a first indoor heat exchanger and a second indoor heat exchanger,
The indoor unit further includes a control device that controls the operation of the switching device,
The control device controls the switching device so that the indoor air passes through the second indoor heat exchanger, thereby suppressing the amount of heat exchanged by the first indoor heat exchanger in the supply air passage. 1. The air conditioner according to 1.
The indoor heat exchanger comprises a first indoor heat exchanger and a second indoor heat exchanger,
The indoor unit further includes a control device that controls the operation of the switching device,
The switching device is capable of adjusting the amount of air that the indoor air passes through the second indoor heat exchanger,
The control device adjusts the amount of heat exchanged by the first indoor heat exchanger in the supply air passage by controlling the switching device so as to adjust the air volume of the indoor air passing through the second indoor heat exchanger. The air conditioner according to claim 1, wherein
The indoor heat exchanger comprises a first indoor heat exchanger and a second indoor heat exchanger,
The indoor unit further includes a control device that controls the operation of the switching device,
The first indoor heat exchanger is positioned in the supply air passage, and the second indoor heat exchanger is switched between the outdoor air and the indoor air by the control device controlling the switching device. 2. The air conditioner according to claim 1, located in a common air path that can be switched to pass through one of them.
The indoor unit further comprises a total heat exchanger that exchanges heat between the outdoor air and the indoor air,
The air conditioner according to any one of claims 2 to 4, wherein the switching device is capable of switching whether the indoor air flowing through the exhaust air passage passes through the total heat exchanger. .
The switching device includes a first damper that switches whether the indoor air passes through the second indoor heat exchanger, and a second damper that switches whether the indoor air passes through the total heat exchanger. with
The control device allows the indoor air to pass through the second indoor heat exchanger when the temperature of the supply air taken into the room is higher than a preset lower limit value and the indoor air temperature is lower than the outdoor air temperature. 6. The air conditioner according to claim 5, wherein the first damper is controlled so as not to prevent the indoor air from passing through the total heat exchanger, and the second damper is controlled so that the indoor air passes through the total heat exchanger.
The switching device includes a first damper that switches whether the indoor air passes through the second indoor heat exchanger, and a second damper that switches whether the indoor air passes through the total heat exchanger. with
The control device allows the indoor air to pass through the second indoor heat exchanger when the temperature of the supply air taken into the room is higher than a preset lower limit and the indoor air temperature is higher than the outdoor air temperature. 6. The air conditioner according to claim 5, wherein said first damper is controlled so as not to pass through said total heat exchanger, and said second damper is controlled so that said room air does not pass through said total heat exchanger.
The switching device includes a first damper that switches whether the indoor air passes through the second indoor heat exchanger, and a second damper that switches whether the indoor air passes through the total heat exchanger. with
The control device controls the first damper so that the indoor air passes through the second indoor heat exchanger when the temperature of the supply air taken into the room is lower than a preset lower limit, and The air conditioner according to claim 5, wherein said second damper is controlled so that indoor air does not pass through said total heat exchanger.
The switching device includes a first damper that can increase or decrease the amount of the indoor air passing through the second indoor heat exchanger, and a second damper that switches whether the indoor air passes through the total heat exchanger. with
The control device operates the first damper so that the volume of the indoor air passing through the second indoor heat exchanger is reduced when the temperature of the supply air taken into the room is higher than a preset target value. and controlling the first damper so that the amount of the indoor air passing through the second indoor heat exchanger increases when the temperature of the supplied air is lower than a preset target value. Item 6. The air conditioner according to item 5.
The switching device includes a first damper group that switches whether the indoor air or the outdoor air passes through the second indoor heat exchanger, and a damper group that switches whether the indoor air passes through the total heat exchanger. and a switching second damper,
The controller controls the outdoor air to pass through the second indoor heat exchanger when the temperature of the supply air taken into the room is higher than a preset lower limit and the indoor air temperature is lower than the outdoor air temperature. 6. The air conditioner according to claim 5, wherein said first damper group is controlled to allow said room air to pass through said total heat exchanger, and said second damper is controlled to pass said total heat exchanger.
The switching device includes a first damper group that switches whether the indoor air or the outdoor air passes through the second indoor heat exchanger, and a damper group that switches whether the indoor air passes through the total heat exchanger. and a switching second damper,
When the temperature of the supply air taken into the room is higher than a preset lower limit and the indoor air temperature is higher than the outdoor air temperature, the outdoor air passes through the second indoor heat exchanger. 6. The air conditioner according to claim 5, wherein said first damper group is controlled so as to prevent said room air from passing through said total heat exchanger.
The switching device includes a first damper group that switches whether the indoor air or the outdoor air passes through the second indoor heat exchanger, and a damper group that switches whether the indoor air passes through the total heat exchanger. and a switching second damper,
The control device controls the first damper group so that the indoor air passes through the second indoor heat exchanger when the temperature of the supply air taken into the room is lower than a preset lower limit, The air conditioner according to claim 5, wherein said second damper is controlled so that said indoor air does not pass through said total heat exchanger.
The switching device includes a first damper that switches whether the indoor air passes through the second indoor heat exchanger, and a second damper that switches whether the indoor air passes through the total heat exchanger. with
The control device controls the first damper so that the indoor air passes through the second indoor heat exchanger when the outdoor air temperature is lower than the freezing temperature, and the indoor air passes through the total heat exchanger. The air conditioner according to claim 5, wherein said second damper is controlled to pass through.