JP6773100B2 - Air conditioner - Google Patents

Description

The present disclosure relates to an air conditioner.

Conventionally, as an air conditioner, as disclosed in Japanese Patent Application Laid-Open No. 2004-108618 (Patent Document 1), after performing a first dehumidifying operation having a large sensible heat capacity, the air conditioner becomes more visible than the first dehumidifying operation. Some perform a second dehumidifying operation with a small thermal capacity.

Japanese Unexamined Patent Publication No. 2004-108618

The conventional air conditioner has a problem that the humidity in the room rises when the first dehumidification operation is switched to the second dehumidification operation, that is, a so-called humidity return occurs.

An object of the present disclosure is to provide an air conditioner capable of suppressing humidity return after shifting from the first dehumidifying operation to the second dehumidifying operation.

The air conditioner of the present disclosure is
A refrigerant circuit in which a compressor, an outdoor heat exchanger, an expansion mechanism and an indoor heat exchanger are connected in a ring shape and a refrigerant circulates.
The first dehumidification operation in which substantially all of the indoor heat exchanger is in the evaporation region and a part of the indoor heat exchanger in the evaporation region, while the remaining part of the indoor heat exchanger is in the overheating region. Equipped with a control unit that performs the second dehumidification operation
The control unit starts the second dehumidifying operation when the frequency of the compressor at the first start when the second dehumidifying operation starts following the first dehumidifying operation is stopped when the air conditioning operation is stopped. The frequency of the compressor at the second start is higher than the frequency of the compressor, and the opening degree of the expansion mechanism at the first start is larger than the opening degree of the expansion mechanism at the second start. , Control the compressor and expansion mechanism.

According to the above configuration, the control unit controls the compressor and the expansion mechanism, so that the frequency of the compressor at the first start can be made higher than the frequency of the compressor at the second start, and The opening degree of the expansion mechanism at the first start can be made larger than the opening degree of the expansion mechanism at the second start. Therefore, it is possible to suppress the return of humidity after shifting from the first dehumidifying operation to the second dehumidifying operation.

One aspect of the air conditioner is
A first refrigerant temperature sensor that detects the temperature of the refrigerant decompressed by the expansion mechanism is provided.
After the start of the second dehumidifying operation, the control unit adjusts the opening degree of the expansion mechanism by using the temperature of the refrigerant detected by the first refrigerant temperature sensor.

According to the above aspect, after the start of the second dehumidification operation, the temperature of the refrigerant detected by the first refrigerant temperature sensor is used to adjust the opening degree of the expansion mechanism, whereby the evaporation region and the superheat region of the indoor heat exchanger are used. The controllability for the size of is increased.

One aspect of the air conditioner is
Equipped with an indoor temperature sensor that detects the indoor temperature
The control unit performs the second dehumidification operation when the temperature difference obtained by subtracting the set temperature from the room temperature is equal to or less than the first predetermined value and equal to or greater than the second predetermined value smaller than the first predetermined value.

According to the above aspect, when the indoor heat load stage is divided into three stages of high heat load, medium heat load and low heat load, the second dehumidifying operation sets the set temperature from the room temperature detected by the room temperature sensor. Since it is performed when the subtracted temperature difference is equal to or less than the first predetermined value and greater than or equal to the second predetermined value (<first predetermined value), the medium heat load should be efficiently reduced while suppressing an excessive decrease in the room temperature. Can be done.

In one aspect of the air conditioner,
The indoor heat exchanger has a control valve and
When the temperature difference becomes smaller than the second predetermined value, the control unit sets the portion upstream of the control valve as the condensation region in the indoor heat exchanger, while the control valve in the indoor heat exchanger. The third dehumidifying operation is performed with the portion downstream of the evaporation area as the evaporation area.

According to the above aspect, when the heat load in the room to be air-conditioned is divided into three stages of high heat load, medium heat load and low heat load, the third dehumidification operation is set from the room temperature detected by the room temperature sensor. Since this is performed when the temperature difference obtained by subtracting the temperature becomes smaller than the second predetermined value (<first predetermined value), it is possible to efficiently reduce the low heat load while suppressing an excessive decrease in the room temperature.

One aspect of the air conditioner is
A second refrigerant temperature sensor provided near the upstream side or the downstream side of the control valve and detecting the temperature of the refrigerant flowing in the indoor heat exchanger is provided.
After the start of the second dehumidifying operation, the control unit adjusts the opening degree of the expansion mechanism by using the temperature of the refrigerant detected by the second refrigerant temperature sensor.

According to the above aspect, when the control unit adjusts the opening degree of the expansion mechanism, the temperature of the refrigerant detected by the second refrigerant temperature sensor after the start of the second dehumidifying operation is used for adjusting the opening degree of the expansion mechanism. As a result, the controllability of the size of the evaporation region and the superheat region of the indoor heat exchanger is improved.

One aspect of the air conditioner is
A second refrigerant temperature sensor provided in the middle portion of the refrigerant path of the indoor heat exchanger and detecting the temperature of the refrigerant flowing in the intermediate portion is provided.
After the start of the second dehumidifying operation, the control unit adjusts the opening degree of the expansion mechanism by using the temperature of the refrigerant detected by the second refrigerant temperature sensor.

Here, the intermediate portion of the refrigerant path means an intermediate portion in the length direction of the refrigerant path. For example, when the refrigerant path is divided into three equal parts, the remaining portion excluding the portions on both ends of the refrigerant path. Is the middle part.

According to the above aspect, when the control unit adjusts the opening degree of the expansion mechanism, the temperature of the refrigerant detected by the second refrigerant temperature sensor after the start of the second dehumidifying operation is used for adjusting the opening degree of the expansion mechanism. As a result, the controllability of the size of the evaporation region and the superheat region of the indoor heat exchanger is improved.

It is a circuit diagram of the refrigerant circuit of the air conditioner of 1st Embodiment of this disclosure. It is a control block diagram of the said air conditioner. It is a schematic diagram for demonstrating the cooling dehumidification operation of the said air conditioner. It is a schematic diagram for demonstrating the overthrottle dehumidification operation of the said air conditioner. It is a schematic diagram for demonstrating the reheat dehumidification operation of the said air conditioner. It is a Moriel diagram at the time of the cooling dehumidification operation, the over-throttle dehumidification operation, and the reheat dehumidification operation of the air conditioner. It is a flowchart about control at the start of the over-throttle dehumidification operation. It is a circuit diagram of the refrigerant circuit of the air conditioner of the 2nd Embodiment of this disclosure. It is a control block diagram of the said air conditioner. It is a circuit diagram of the refrigerant circuit of the modification of the said air conditioner.

Hereinafter, the air conditioner of the present disclosure will be described in detail with reference to the illustrated embodiment.

[First Embodiment]
FIG. 1 is a circuit diagram of a refrigerant circuit RC included in the air conditioner of the first embodiment of the present disclosure.

The air conditioner includes an indoor unit 1 installed indoors to be air-conditioned and an outdoor unit 2 installed outdoors.

The indoor unit 1 is, for example, a wall-mounted indoor unit that is attached to a wall surface of the room. The indoor unit 1 uses an indoor heat exchanger 11, an indoor fan 12 that sends air to the indoor heat exchanger 11, an indoor heat exchanger temperature sensor 51 that detects the temperature of the indoor heat exchanger 11, and an indoor temperature. It has an indoor temperature sensor 52 for detecting and an indoor humidity sensor 53 for detecting indoor humidity.

The indoor heat exchanger 11 is located on the upstream side of the indoor fan 12 with respect to the air flow by the indoor fan 12. The indoor heat exchanger 11 includes a main body heat exchange unit 11a, an auxiliary heat exchange unit 11b, and an electromagnetic valve 13 as an example of a control valve in order to exchange heat between the air from the indoor fan 12 and the refrigerant. Have.

The main body heat exchange portion 11a includes a front portion 11a-1 located on the indoor user side and a back portion 11a-2 located on the side opposite to the indoor user side. Further, the front portion 11a-1 is fluidly connected to the back portion 11a-2 via the refrigerant pipes L1 and L2 and the solenoid valve 13. As a result, the refrigerant flowing from the expansion valve 24 to the main body heat exchange portion 11a can flow into the back portion 11a-2 after flowing through the front portion 11a-1.

The auxiliary heat exchange portion 11b is provided on the side opposite to the back surface portion 11a-2 side of the main body heat exchange portion 11a with respect to the front portion 11a-1 of the main body heat exchange portion 11a. That is, the auxiliary heat exchange unit 11b is located closer to the indoor user than the front portion 11a-1 of the main body heat exchange unit 11a. The volume of the auxiliary heat exchange unit 11b is smaller than that of the main body heat exchange unit 11a. Further, the auxiliary heat exchange portion 11b is fluidly connected to the front portion 11a-1 of the main body heat exchange portion 11a via the refrigerant pipe L11. As a result, the refrigerant from the expansion valve 24 side is supplied to the main body heat exchange unit 11a via the auxiliary heat exchange unit 11b. As described above, it can be said that the auxiliary heat exchange unit 11b has a refrigerant path between the refrigerant pipe L3 and the refrigerant pipe L11.

As the indoor fan 12, for example, a cross flow fan is adopted. This cross-flow fan blows out air whose temperature and the like are adjusted by the indoor heat exchanger 11 toward the room.

The solenoid valve 13 is provided in the middle portion of the refrigerant path of the indoor heat exchanger 11. More specifically, it is a valve for setting a differential pressure between the front portion 11a-1 side of the main body heat exchange portion 11a and the front portion 11a-1 side of the main body heat exchange portion 11a. The solenoid valve 13 is an on / off valve that can take only two positions, a large opening and a small opening, and is turned on when necessary (for example, during reheat dehumidification operation described later) and slightly opened from the position of the large opening. It can be switched to the degree position.

The outdoor unit 2 includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an expansion valve 24 as an example of an expansion mechanism, an accumulator 25, and an outdoor fan that sends air to the outdoor heat exchanger 23. It has 26 and. Further, the outdoor unit 2 includes an outdoor heat exchanger temperature sensor 56 that detects the temperature of the outdoor heat exchanger 23, an outside air temperature sensor 57 that detects the outside air temperature, and the temperature (evaporation temperature) of the refrigerant decompressed by the expansion valve 24. ) Is detected by the refrigerant temperature sensor 58. The refrigerant temperature sensor 58 is an example of the first refrigerant temperature sensor.

The outdoor heat exchanger 23 is located on the downstream side of the outdoor fan 26 with respect to the air flow by the outdoor fan 26. The refrigerant flowing in the outdoor heat exchanger 23 exchanges heat with the air from the indoor fan 12.

The expansion valve 24 is, for example, an electric valve that can be adjusted to three or more opening degrees different from each other, and the opening degree changes according to a signal from the control device 100 (shown in FIG. 2).

Further, the refrigerant circuit RC of the air conditioner includes an indoor heat exchanger 11, a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23, an expansion valve 24, an accumulator 25, and refrigerant pipes L3 to L9. .. More specifically, the indoor heat exchanger 11, the compressor 21, the four-way switching valve 22, the outdoor heat exchanger 23, the expansion valve 24, and the accumulator 25 are fluidly connected by the refrigerant pipes L3 to L9. As a result, the annular refrigerant circuit RC is configured. In such a refrigerant circuit RC, the refrigerant circulates when the compressor 21 is driven.

Although not shown, the air conditioner includes a remote controller (hereinafter, referred to as "remote controller"). The user can operate the remote controller to start or stop automatic operation, cooling operation, heating operation, dehumidifying operation, and the like.

FIG. 2 is a control block diagram of the air conditioner.

The air conditioner includes a control device 100 that controls the refrigerant circuit RC. More specifically, the control device 100 includes a microcomputer, an input / output circuit, and the like. The control device 100 compresses based on signals from the indoor heat exchanger temperature sensor 51, the indoor temperature sensor 52, the indoor humidity sensor 53, the outdoor heat exchanger temperature sensor 56, the outside air temperature sensor 57, the refrigerant temperature sensor 58, and the like. It controls the machine 21, the four-way switching valve 22, the expansion valve 24, the outdoor fan 26, the indoor fan 12, the electromagnetic valve 13, and the like. The control device 100 is an example of a control unit.

Further, the control device 100 includes a cooling dehumidification operation control unit 100a that performs a cooling dehumidification operation, an overthrottle dehumidification operation control unit 100b that performs an overslot dehumidification operation, and a reheat dehumidification operation control unit 100c that performs a reheat dehumidification operation. Have. The cooling dehumidification operation control unit 100a, the over-throttle dehumidification operation control unit 100b, and the reheat dehumidification operation control unit 100c are each composed of software. The cooling dehumidification operation is an example of the first dehumidification operation. The over-throttle dehumidification operation is an example of the second dehumidification operation. The reheat dehumidification operation is an example of the third dehumidification operation.

[Cooling and dehumidifying operation]
As shown in FIG. 1, the cooling / dehumidifying operation is started by switching the four-way switching valve 22 to the solid line switching position and activating the compressor 21. During this cooling / dehumidifying operation, the high-temperature and high-pressure refrigerant discharged from the compressor 21 flows into the outdoor heat exchanger 23 via the four-way switching valve 22. Then, the refrigerant condensed by the outdoor heat exchanger 23 is decompressed by the expansion valve 24, and then the auxiliary heat exchange portion 11b of the indoor heat exchanger 11 and the main body heat exchange portion 11a of the indoor heat exchanger 11 are subjected to this. Inflow in order. The refrigerant evaporated in the main body heat exchange section 11a and the auxiliary heat exchange section 11b returns to the suction side of the compressor 21 via the four-way switching valve 22 and the accumulator 25. In this way, when the refrigerant circulates in the refrigerant circuit RC, the cooling / dehumidifying operation control unit 100a adjusts the frequency of the compressor 21 and the opening degree of the expansion valve 24, and turns off the solenoid valve 13. As shown in FIG. 3, substantially the entire indoor heat exchanger 11 is defined as an evaporation region (the region shaded in FIG. 3). As a result, the cooling / dehumidifying operation has a high sensible heat capacity, which is the ability to change the room temperature.

Here, to make substantially all of the indoor heat exchanger 11 an evaporation region is not only when the entire indoor heat exchanger 11 is made into an evaporation region, but also a part of the indoor heat exchanger 11 under predetermined conditions. It also includes the case where only the excluded part is set as the evaporation area. As a predetermined condition that only a part of this (for example, a portion of 1/3 or less of the total volume of the indoor heat exchanger 11) does not become an evaporation region, for example, depending on the indoor environment or the like, in the vicinity of the refrigerant outlet of the indoor heat exchanger 11. There are times when the part becomes an overheated area.

[Over-throttle dehumidification operation]
In the over-throttle dehumidification operation, the refrigerant flows in the same direction as in the cooling dehumidification operation. At this time, the over-throttle dehumidification operation control unit 100b adjusts the frequency of the compressor 21 and the opening degree of the expansion valve 24, and turns off the solenoid valve 13 to turn off the electromagnetic valve 13 so as to be one on the upstream side of the indoor heat exchanger 11. The portion is set as an evaporation region, while the remaining portion of the indoor heat exchanger 11 is set as a superheat region. For example, as shown in FIG. 4, the over-throttle dehumidification operation control unit 100b sets the auxiliary heat exchange unit 11b into an evaporation region (a region with hatched diagonal lines), while the front portion 11a-1 of the main body heat exchange unit 11a. And the back surface portion 11a-2 is set to a superheated region (area with hatched dots). As a result, the sensible heat capacity of the over-squeezing dehumidifying operation is lower than that of the cooling dehumidifying operation. Therefore, when the heat load in the room is neither high nor low, the room can be dehumidified while suppressing the decrease in room temperature. In FIG. 4, the entire auxiliary heat exchange unit 11b is drawn so as to be in the evaporation region, but it is also possible to set only a part of the auxiliary heat exchange unit 11b as the evaporation region. That is, the evaporation region is a variable region whose volume can be changed.

Further, the compressor 21 and the expansion valve 24 are controlled so that the volume of the evaporation region changes according to the load during the over-throttle dehumidification operation. For example, the over-throttle dehumidification operation control unit 100b has a compressor 21 and an expansion valve so that the evaporation area becomes a predetermined volume (for example, 2/3 of the total volume of the indoor heat exchanger 11) during the over-throttle dehumidification operation. 24 is controlled.

Here, what changes according to the load means that it changes according to the amount of heat supplied from the room to the evaporation area, and the amount of heat is, for example, the indoor temperature (the temperature of the air sucked by the indoor unit 1) and the amount of indoor air. It is determined by (the amount of air blown by the indoor unit 1). Further, the load corresponds to the required dehumidifying capacity (required cooling capacity), and can be detected based on, for example, the difference between the room temperature and the set temperature. As the set temperature, a preset temperature or a temperature set by the user with the remote controller is used.

[Reheat dehumidification operation]
In the reheat dehumidification operation, the refrigerant flows in the same direction as in the cooling dehumidification operation. At this time, the reheat dehumidification operation control unit 100c adjusts the frequency of the compressor 21 and the opening degree of the expansion valve 24, and turns on the solenoid valve 13 so that the room heat exchanger 11 is connected to the solenoid valve 13. At least a part of the upstream side is set as a condensation area, while at least a part of the room heat exchanger 11 on the downstream side of the solenoid valve 13 is set as an evaporation area. For example, as shown in FIG. 5, the reheat dehumidification operation control unit 100c sets the auxiliary heat exchange unit 11b and the front surface portion 11a-1 of the main body heat exchange unit 11a into a condensation region (a region with hatched lattices). On the other hand, the back surface portion 11a-2 of the main body heat exchange portion 11a is set as an evaporation region (a region with shaded hatching). As a result, the reheat dehumidification operation has a lower sensible heat capacity than the over-squeeze dehumidification operation. Therefore, when the heat load in the room is low, the room can be dehumidified while suppressing the decrease in room temperature.

Further, in the reheat dehumidification operation, the solenoid valve 13 is switched to a position having a small opening degree. That is, the opening degree of the solenoid valve 13 in the reheat dehumidification operation is an opening degree corresponding to an air flow rate of less than 10 L / min. The opening degree of the solenoid valve 13 in the reheat dehumidification operation is preferably an opening degree corresponding to an air flow rate of 5 L / min. Further, the opening degree of the solenoid valve 13 in the reheat dehumidification operation is preferably an opening degree corresponding to an air flow rate of 3.5 L / min. Here, "the opening degree of the solenoid valve 13 in the reheat dehumidifying operation is an opening degree corresponding to an air flow rate of less than 10 L / min" means that the air flow rate flowing through the refrigerant circuit RC at the said opening degree is 10 L / min. It does not mean that it is less than min, but that the air flow rate at the opening degree obtained from the flow rate characteristics of the solenoid valve 13 is less than 10 L / min.

The cooling dehumidifying operation, the over-squeezing dehumidifying operation, or the reheat dehumidifying operation is started in response to pressing the button of the dehumidifying operation of the remote controller. More specifically, when the dehumidification operation button is pressed, one of the cooling dehumidification operation, the over-squeeze dehumidification operation, and the reheat dehumidification operation is automatically selected based on, for example, the sensible heat ratio. To start. After that, it automatically switches to another dehumidifying operation according to the change in the sensible heat ratio. The sensible heat ratio refers to the ratio of sensible heat to total heat (= sensible heat + latent heat).

FIG. 6 is a Moriel diagram during the cooling dehumidification operation, the over-throttle dehumidification operation, and the reheat dehumidification operation of the air conditioner.

The control of the over-throttle dehumidification operation control unit 100b is performed so that the evaporation temperature of the over-throttle dehumidification operation is lower than the evaporation temperature of the cooling dehumidification operation. At this time, the opening degree of the expansion valve 24 is usually smaller than the opening degree of the expansion valve 24 during the cooling / dehumidifying operation.

The control of the reheat dehumidification operation control unit 100c is performed so that the evaporation temperature of the reheat dehumidification operation is lower than the evaporation temperature of the over-throttle dehumidification operation. At this time, the opening degree of the expansion valve 24 is fixed to an opening degree larger than the maximum opening degree of the expansion valve 24 during the over-throttle dehumidification operation.

Further, under the control of the over-throttle dehumidification operation control unit 100b, the frequency of the compressor 21 is set to air conditioning when the over-throttle dehumidification operation starts following the cooling dehumidification operation (hereinafter referred to as "first start time"). It differs from the time when the over-throttle dehumidification operation starts from the time when the operation is stopped (hereinafter, referred to as "the second start time"). More specifically, the frequency of the compressor 21 at the first start is higher than the frequency of the compressor 21 at the second start. Further, the opening degree of the expansion valve 24 at the first start is larger than the opening degree of the expansion valve 24 at the second start.

Further, the over-throttle dehumidification operation control unit 100b adjusts the opening degree of the expansion valve 24 by using the evaporation temperature detected by the refrigerant temperature sensor 58 after the start of the over-throttle dehumidification operation. More specifically, the opening degree of the expansion valve 24 is set so that the evaporation temperature becomes a predetermined temperature (for example, 10 ° C.) and the middle portion of the refrigerant path of the indoor heat exchanger 11 becomes a superheat region. Is adjusted.

Further, the over-throttle dehumidification operation control unit 100b performs the over-squeeze dehumidification operation when the temperature difference obtained by subtracting the set temperature from the room temperature detected by the room temperature sensor 52 is within a predetermined range. Here, the above-mentioned predetermined range is, for example, a range satisfying the first predetermined value (for example, +1.0 deg) or less and the second predetermined value (for example, -1.0 deg) smaller than the first predetermined value. Point to. As the set temperature, a preset temperature or a temperature set by the user with the remote controller is used.

Further, the reheat dehumidification operation control unit 100c performs the reheat dehumidification operation when the absolute value of the temperature difference is smaller than the second predetermined value.

In the air conditioner having the above configuration, the cooling / dehumidifying control unit 100a controls the compressor 21 and the expansion valve 24. As a result, the frequency of the compressor 21 is higher at the first start of the over-throttle dehumidification operation that is performed following the cooling dehumidification operation than at the second start of the over-throttle dehumidification operation that is performed from the stop of the air conditioning operation. It becomes high and the opening degree of the expansion valve 24 becomes large. As a result, when shifting from the cooling dehumidifying operation to the over-squeezing dehumidifying operation, the size of the evaporation region can be gradually changed, so that the humidity return after the transition can be suppressed.

Further, after the over-throttle dehumidification operation control unit 100b starts the over-throttle dehumidification operation, the evaporation temperature detected by the refrigerant temperature sensor 58 is used for adjusting the opening degree of the expansion valve 24 to evaporate the indoor heat exchanger 11. Greater control over the size of the region and overheated region.

Further, when the indoor heat load stage is divided into three stages of high heat load, medium heat load and low heat load, the over-throttle dehumidification operation control unit 100b has a predetermined temperature difference between the room temperature and the set temperature. When the difference is greater than or equal to the difference, the over-squeezing dehumidifying operation is performed, so that the medium heat load can be efficiently reduced while suppressing the decrease in the indoor temperature.

Further, since the over-throttle dehumidification operation control unit 100b is not performed when the temperature difference is less than the predetermined temperature difference, it is not necessary to deal with the low heat load by the over-throttle dehumidification operation. Therefore, it is possible to prevent the efficiency of the over-throttle dehumidification operation from deteriorating.

Further, in that case, the reheat dehumidification operation control unit 100c performs reheat dehumidification when the temperature difference is less than the predetermined temperature difference, so that the low heat load can be efficiently reduced while suppressing the decrease in the room temperature. Can be done.

Hereinafter, control at the start of the over-throttle dehumidification operation will be described with reference to the flowchart of FIG. 7. The above control is performed, for example, when the over-throttle dehumidification operation is started after the dehumidification operation button on the remote controller is pressed.

When the above control is started, first, in step S1, it is determined whether or not the immediately preceding operation was the cooling / dehumidifying operation. If it is determined in step S1 that the immediately preceding operation was the cooling / dehumidifying operation, the process proceeds to the next step S2. On the other hand, if it is determined in step S1 that the immediately preceding operation is not the cooling / dehumidifying operation, the control ends via step S11. As an example when the immediately preceding operation is not the cooling dehumidification operation, there is a case where the air conditioning operation is stopped, the reheat dehumidification operation is performed immediately before, and the like.

In step S11, the compressor is set so that the frequency of the compressor 21 becomes the default start frequency of the over-throttle dehumidification operation and the opening degree of the expansion valve 24 becomes the default start opening degree of the over-throttle dehumidification operation. 21 and the expansion valve 24 are controlled. The step S11 is performed by the over-throttle dehumidification operation control unit 100b.

Next, in step S2, it is determined whether or not the heat load in the room is a medium heat load. That is, in step S2, the temperature difference obtained by subtracting the set temperature from the room temperature detected by the room temperature sensor 52 is the first predetermined value (for example, +1.0 deg) or less and smaller than the first predetermined value. It is determined whether or not it is equal to or more than a predetermined value (for example, −1.0 deg). If it is determined in step S2 that the absolute value of the temperature difference is equal to or less than the first predetermined value and equal to or greater than the second predetermined value, the process proceeds to the next step S3. On the other hand, if it is determined in step S2 that the absolute value of the temperature difference is larger than the first predetermined value or smaller than the second predetermined value, the control ends.

Finally, in step S3, the compressor 21 and expansion are made so that the frequency of the compressor 21 is higher than the default start frequency and the opening degree of the expansion valve 24 is larger than the default start opening. By controlling the valve 24, the above control becomes the end. After the end of the control is reached, for example, the determination made immediately after pressing the dehumidifying operation button is performed again. Further, step S3 is performed by the over-throttle dehumidification operation control unit 100b.

Therefore, when the cooling dehumidification operation is switched to the over-throttle dehumidification operation, the frequency of the compressor 21 can be made higher than the default start frequency of the over-throttle dehumidification operation by step S3, and the opening degree of the expansion valve 24 is opened. Can be made larger than the default start opening of the over-throttle dehumidification operation.

In the first embodiment, the indoor heat exchanger 11 has a main body heat exchange unit 11a and an auxiliary heat exchange unit 11b, but has a main body heat exchange unit 11a but does not have an auxiliary heat exchange unit 11b. You may do so. In this case, during the over-throttle dehumidification operation, only a part of the main body heat exchange unit 11a may be in the evaporation region.

In the first embodiment, the solenoid valve 13 is provided between the front portion 11a-1 side of the main body heat exchange portion 11a and the front portion 11a-1 side of the main body heat exchange portion 11a. An electric valve that can be adjusted to the opening degree of the above may be provided as an example of the control valve.

In the first embodiment, the control device 100 may be composed of an indoor control unit (not shown) on the indoor unit 1 side and an outdoor control unit (not shown) on the outdoor unit 2 side. It may be composed only of the indoor control unit, or may be composed only of the outdoor control unit. In other words, the control device 100 may be partially mounted on the indoor unit 1 and the remaining other portion mounted on the outdoor unit 2, or the entire control device 100 may be mounted on the indoor unit 1. It may be mounted, or all of them may be mounted on the outdoor unit 2.

In the first embodiment, the cooling dehumidifying operation control unit 100a, the over-squeezing dehumidifying operation control unit 100b, and the reheat dehumidifying operation control unit 100c are respectively composed of software, but the cooling dehumidifying operation control unit 100a and the over-squeezing At least one of the dehumidifying operation control unit 100b and the reheat dehumidifying operation control unit 100c may be configured by hardware.

In the first embodiment, the control of the flowchart of FIG. 7 is performed when the over-squeezing dehumidifying operation is started after the dehumidifying operation button of the remote controller is pressed. For example, the automatic operation button of the remote controller is used. This may be performed when the over-throttle dehumidification operation is started after is pressed. Here, in the above automatic operation, one of the cooling operation, the dehumidifying operation, the heating operation, etc. is automatically selected and started based on the indoor temperature, the outdoor temperature, etc., and then automatically switched to the other air conditioning operation. Is. In this automatic dehumidifying operation, the over-squeezing dehumidifying operation may be automatically started. Further, in the dehumidifying operation of the automatic operation, the cooling dehumidifying operation, the over-squeezing dehumidifying operation, and the reheat dehumidifying operation may be automatically switched to each other in response to a change in the sensible heat ratio, for example.

In the first embodiment, the process of step S3 is performed when shifting from the cooling dehumidifying operation to the over-squeezing dehumidifying operation, but it may be performed when shifting from the cooling operation to the over-squeezing dehumidifying operation. Good. In this case, the cooling operation is an example of the first dehumidifying operation.

In the first embodiment, after the process of step S3, the frequency of the compressor 21 and the opening degree of the expansion valve 24 may be maintained for a predetermined time.

[Second Embodiment]
FIG. 8 is a circuit diagram of a refrigerant circuit RC included in the air conditioner of the second embodiment of the present disclosure. In addition, in FIG. 8, the same constituent part as the constituent part of FIG. 1 is given the same reference number as the reference number of the constituent part of FIG.

The indoor unit 201 of the air conditioner includes a refrigerant temperature sensor 261 provided near the upstream side of the solenoid valve 13. The refrigerant temperature sensor 261 is attached to the refrigerant pipe L1 and detects the temperature of the refrigerant in the refrigerant pipe L1. The refrigerant temperature sensor 261 is an example of the second refrigerant temperature sensor.

FIG. 9 is a control block diagram of the air conditioner. In addition, in FIG. 9, the same component as the component of FIG. 2 has the same reference number as the reference number of the component of FIG.

The air conditioner includes a control device 200 including a microcomputer, an input / output circuit, and the like. The control device 200 has an over-throttle dehumidification operation control unit 200b different from the over-squeeze dehumidification operation control unit 100b of the first embodiment.

At the start of the over-throttle dehumidification operation performed following the cooling dehumidification operation, the over-throttle dehumidification operation control unit 200b determines the frequency of the compressor 21 and the opening degree of the expansion valve 24, similarly to the over-throttle dehumidification operation control unit 100b. Control. Further, the over-throttle dehumidification operation control unit 200b adjusts the opening degree of the expansion valve 24 by using the temperature of the refrigerant detected by the refrigerant temperature sensor 261 after the start of the over-throttle dehumidification operation.

The air conditioner having the above configuration has the same effects as those of the first embodiment.

Further, the over-throttle dehumidification operation control unit 200b uses the temperature of the refrigerant detected by the refrigerant temperature sensor 261 after the start of the over-throttle dehumidification operation to adjust the opening degree of the expansion valve 24, whereby the indoor heat exchanger 11 The controllability for the size of the evaporation region and the superheat region of the above is higher than that of the first embodiment.

In the second embodiment, the indoor heat exchanger 11 has the solenoid valve 13, but the refrigerant temperature sensor is located in the middle of the refrigerant path of the indoor heat exchanger 11 so as not to have the solenoid valve 13. You may just provide 261.

In the second embodiment, the refrigerant temperature sensor 261 in the indoor unit 201 is provided near the upstream side of the solenoid valve 13, but is provided near the downstream side of the solenoid valve 13, for example, as shown in FIG. May be good. In this case, the refrigerant temperature sensor 261 may be attached to, for example, the refrigerant pipe L2. Further, the mounting position of the refrigerant temperature sensor 261 may be other than the refrigerant pipes L1 and L2, and may be any position as long as the temperature of the refrigerant flowing in the middle portion of the refrigerant path of the indoor heat exchanger 11 can be detected.

Although specific embodiments of the present disclosure have been described, the present disclosure is not limited to the above-described embodiments and variations thereof, and various modifications can be made within the scope of the present disclosure. For example, a modified example of the second embodiment applied to the first embodiment or a modified example of the first embodiment applied to the second embodiment may be an embodiment of the present disclosure.

1 Indoor unit 2 Outdoor unit 11 Indoor heat exchanger 11a Main body heat exchange part 11a-1 Front part 11a-2 Back part 11b Auxiliary heat exchange part 13 Electromagnetic valve 12 Indoor fan 21 Compressor 22 Four-way switching valve 23 Outdoor heat exchanger 24 Expansion valve 25 Accumulator 26 Outdoor fan 51 Indoor heat exchanger temperature sensor 52 Indoor temperature sensor 53 Indoor humidity sensor 56 Outdoor heat exchanger temperature sensor 57 Outdoor air temperature sensor 58,261 Refrigerant temperature sensor 100 Control device 100a Cooling and dehumidifying operation control unit 100b , 200b Over-throttle dehumidification operation control unit 100c Reheat dehumidification operation control unit RC refrigerant circuit

Claims (6)

A refrigerant circuit (RC) in which a compressor (21), an outdoor heat exchanger (23), an expansion mechanism (24) and an indoor heat exchanger (11) are connected in a ring shape and a refrigerant circulates.
The first dehumidifying operation in which substantially all of the indoor heat exchanger (11) is in the evaporation region, and the indoor heat exchanger (11) while making a part of the indoor heat exchanger (11) in the evaporation region. It is equipped with a control unit (100, 200) that performs a second dehumidifying operation that makes the remaining part of the heat exchange area.
In the control unit (100, 200), the frequency of the compressor (21) at the first start when the second dehumidification operation is started following the first dehumidification operation is from the time when the air conditioning operation is stopped. The opening degree of the expansion mechanism (24) at the first start is set to be higher than the frequency of the compressor (21) at the second start when the second dehumidification operation is started. An air conditioner characterized in that the compressor (21) and the expansion mechanism (24) are controlled so as to be larger than the opening degree of the expansion mechanism (24) at the time. In the air conditioner according to claim 1,
A first refrigerant temperature sensor (58) for detecting the temperature of the refrigerant decompressed by the expansion mechanism (24) is provided.
After the start of the second dehumidifying operation, the control unit (100, 200) adjusts the opening degree of the expansion mechanism (24) by using the temperature of the refrigerant detected by the first refrigerant temperature sensor (58). An air conditioner characterized by In the air conditioner according to claim 1 or 2.
Equipped with an indoor temperature sensor (52) that detects the indoor temperature,
When the temperature difference obtained by subtracting the set temperature from the room temperature is equal to or less than the first predetermined value and greater than or equal to the second predetermined value smaller than the first predetermined value, the control unit (100, 200) has the second predetermined value. An air conditioner characterized by performing dehumidifying operation. In the air conditioner according to claim 3,
The indoor heat exchanger (11) has a control valve (13).
When the temperature difference becomes smaller than the second predetermined value, the control unit (100, 200) sets the portion of the indoor heat exchanger (11) upstream of the control valve (13) as the condensation region. On the other hand, the air conditioner characterized in that the indoor heat exchanger (11) performs a third dehumidifying operation with a portion downstream of the control valve (13) as an evaporation region. In the air conditioner according to claim 4,
A second refrigerant temperature sensor (261) provided near the upstream side or the downstream side of the control valve (13) and detecting the temperature of the refrigerant flowing in the indoor heat exchanger (11) is provided.
After the start of the second dehumidifying operation, the control unit (200) adjusts the opening degree of the expansion mechanism (24) by using the temperature of the refrigerant detected by the second refrigerant temperature sensor (261). An air conditioner featuring. In the air conditioner according to claim 1,
A second refrigerant temperature sensor (261) provided in the middle portion of the refrigerant path of the indoor heat exchanger (11) and detecting the temperature of the refrigerant flowing in the intermediate portion is provided.
After the start of the second dehumidifying operation, the control unit (200) adjusts the opening degree of the expansion mechanism (24) by using the temperature of the refrigerant detected by the second refrigerant temperature sensor (261). An air conditioner featuring.

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