WO2019038804A1 - Air conditioning device - Google Patents

Abstract

This air conditioning device capable of heating operations comprises: a refrigerant circuit in which refrigerant circulates and in which a compressor, a first heat exchanger, a throttling device, and a second heat exchanger are connected in order with refrigerant piping; and a control device that controls the compressor and the throttling device. When the set temperature is higher than the discharge temperature during heating operations, the control device varies the control of the degree of subcooling between the case when the condensing temperature is at or higher than a preset target condensing temperature and the case when same is lower than the target condensing temperature.

Description

Air conditioner

The present invention relates to an air conditioner provided with an outdoor unit and an indoor unit, and more particularly to control of the blowout temperature of the indoor unit.

BACKGROUND Conventionally, there is an air conditioner that controls the blowout temperature of an indoor unit during heating operation (see, for example, Patent Document 1).

During the heating operation, the air conditioner described in Patent Document 1 adjusts the opening degree of the expansion device in consideration of the blowout temperature and the blowout temperature target value, and depending on the necessary heat exchange capacity, also considering the degree of supercooling. Thus, the blowout temperature of the indoor unit is controlled.

Specifically, in the heating operation, when the set temperature is higher than the blowout temperature, control is performed to increase the operating frequency of the compressor and the rotational speed of the blower fan. At the same time, control is performed to lower the target degree of subcooling and to increase the opening degree of the expansion device so that the degree of subcooling becomes the target degree of subcooling. By doing so, the blowing temperature of the indoor unit is raised, and the blowing temperature is controlled to the set temperature.

WO 2015/166576

However, in the conventional air conditioner as described in Patent Document 1, the operating frequency of the compressor and the rotational speed of the blower fan under low temperature conditions where the temperature of the air taken in by the indoor unit falls below 0 ° C. Even when MAX became MAX, the blowout temperature did not reach the set temperature, and the blowout temperature could not be controlled to the set temperature. Therefore, there is a problem that the heating capacity can not be exhibited under the low temperature condition.

The present invention has been made to solve the problems as described above, and it is an object of the present invention to provide an air conditioner capable of improving the heating capacity under low temperature conditions during heating operation.

In the air conditioner according to the present invention, a compressor, a first heat exchanger, a throttling device, and a second heat exchanger are sequentially connected by piping, and a refrigerant circuit in which a refrigerant circulates, the compressor, and the throttling device An air conditioner capable of a heating operation, the controller being a target condensation whose condensing temperature is set in advance when the set temperature is higher than the blowing temperature during the heating operation The control of the degree of subcooling is changed depending on whether the temperature is higher or lower than the target condensation temperature.

According to the air conditioner of the present invention, when the set temperature is higher than the blowout temperature during the heating operation, the condensation temperature is higher than or equal to the preset target condensation temperature and lower than the target condensation temperature. Change control of degree of supercooling. By doing so, the heating capacity under low temperature conditions can be improved.

It is a figure showing an example of the air harmony device concerning an embodiment of the invention. It is a functional block diagram of the air harmony device concerning an embodiment of the invention. It is a figure which shows the control flow at the time of heating operation of the air conditioning apparatus which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described based on the drawings. The present invention is not limited by the embodiments described below. Moreover, in the following drawings, the relationship of the magnitude | size of each structural member may differ from an actual thing.

Embodiment.
FIG. 1 is a diagram showing an example of an air conditioning apparatus 100 according to an embodiment of the present invention. The arrows in FIG. 1 indicate the flow of the refrigerant.
An air conditioner 100 according to the present embodiment includes an outdoor unit 10 and an indoor unit 20, and is capable of performing a heating operation. The outdoor unit 10 has a function as a heat source of the indoor unit 20. The indoor unit 20 has a function of using the heat supplied from the outdoor unit 10 to control the temperature of outdoor air taken mainly from the outdoor, and supplying the air to an air conditioning target area such as indoor.

The outdoor unit 10 includes a compressor 11, a second heat exchanger 12, and a blower fan 13. Further, the indoor unit 20 is provided with the first heat exchanger 21 and the expansion device 22.

The compressor 11 is a positive displacement type capable of changing the operating frequency F, and compresses the sucked refrigerant into a high temperature / high pressure state. As a control method for changing the operating frequency F, for example, there is a method by driving a motor controlled by an inverter. The second heat exchanger 12 functions as an evaporator and performs heat exchange between the air and the refrigerant. The blower fan 13 is, for example, a blower unit configured by a propeller fan, and supplies air to the second heat exchanger 12.

The first heat exchanger 21 functions as a condenser or a radiator and performs heat exchange between air and a refrigerant. Although the first heat exchanger 21 is mainly used to control the temperature of outdoor air, it may be used to control the temperature of indoor air. The expansion device 22 has a variable opening degree, functions as a pressure reducing valve or an expansion valve, and decompresses and expands the refrigerant.

The air conditioner 100 further includes a refrigerant circuit 200 in which the compressor 11, the first heat exchanger 21, the expansion device 22, and the second heat exchanger 12 are sequentially connected by a refrigerant pipe, and the refrigerant circulates. There is.

The outdoor unit 10 is provided on the discharge side of the compressor 11 and includes a discharge pressure detection device 14 that detects the pressure of the refrigerant discharged from the compressor 11. The indoor unit 20 further includes a first temperature detection device 23 provided between the first heat exchanger 21 and the expansion device 22 for detecting the temperature of the refrigerant flowing out of the first heat exchanger 21. Furthermore, the indoor unit 20 is provided downstream of the air of the first heat exchanger 21 and includes a second temperature detection device 24 that detects the blowout temperature Tout.

The air conditioning apparatus 100 also includes a control device 50 that controls the operating frequency F of the compressor 11, the number of rotations N of the blower fan 13, the opening degree Sj of the expansion device 22, and the like. The control device 50 includes, for example, a dedicated hardware or a CPU (Central Processing Unit, central processing unit, processing unit, arithmetic unit, microprocessor, microcomputer, processor) that executes a program stored in a memory. Be done.

FIG. 2 is a functional block diagram of the air conditioning apparatus 100 according to the embodiment of the present invention.
As shown in FIG. 2, the control device 50 includes a main control unit 51, a storage unit 52, and a drive unit 53.
The main control unit 51 operates the operating frequency F of the compressor 11 and the rotational speed N of the blower fan 13 (including ON / OFF) based on detection values of various detection devices and an instruction from a remote control (not shown) or the like. The controller 53 instructs the drive unit 53 to control the opening degree Sj of the diaphragm device 22.

The various detection devices include the discharge pressure detection device 14, the first temperature detection device 23, and the second temperature detection device 24.

The storage unit 52 stores various pieces of information such as a target condensation temperature Tcm and a target degree of supercooling SCm described later.

The drive unit 53 controls the operating frequency F of the compressor 11, the rotational speed N (including ON / OFF) of the blower fan 13, and the opening degree Sj of the expansion device 22 based on an instruction from the main control unit 51. It is a thing.

Although the control device 50 includes the storage unit 52 in the present embodiment, the present invention is not limited thereto, and the storage unit 52 may be provided separately from the control device 50.

FIG. 3 is a diagram showing a control flow during heating operation of the air conditioning apparatus 100 according to the embodiment of the present invention.
Hereinafter, control during heating operation of the air conditioning apparatus 100 according to the present embodiment will be described using FIG. 3.
The control device 50 executes the following processing when the set temperature Ts preset by the remote controller or the like is larger than the blowout temperature Tout detected by the second temperature detection device 24 after the heating operation of the air conditioning device 100 is started.

The main control unit 51 compares the condensation temperature Tc converted from the pressure of the refrigerant detected by the discharge pressure detection device 14 with the preset target condensation temperature Tcm stored in the storage unit 52 (step S101).

If the main control unit 51 determines that the condensation temperature Tc is equal to or higher than the target condensation temperature Tcm (Tc ≧ Tcm) (NO in step S101), the process proceeds to step S102.

In step S102, the main control unit 51 causes the drive unit 53 to lower the operating frequency F of the compressor 11 and the rotational speed N of the blower fan 13 so that the condensation temperature Tc becomes the target condensation temperature Tcm. Further, at the same time, the main control unit 51 reduces the target degree of supercooling SCm stored in the storage unit 52 so that the drive unit 53 performs the throttling device so that the degree of subcooling SC becomes the target degree of supercooling SCm. Increase the opening degree Sj of 22. By doing so, the blowout temperature Tout of the indoor unit 20 rises.

Here, the degree of subcooling SC is a value calculated by the difference (Tо−Tc) between the temperature To of the refrigerant detected by the first temperature detection device 23 and the condensation temperature Tc, and SCm is the degree of the degree of supercooling It is a value to be a target value of SC.

On the other hand, when the main control unit 51 determines that the condensing temperature Tc is smaller than the target condensing temperature Tcm (Tc <Tcm) (YES in step S101), the process proceeds to step S103.

In step S103, the main control unit 51 determines whether the operating frequency F of the compressor 11 is MAX and the rotational speed N of the blower fan 13 is MAX (step S103). Here, MAX of the operating frequency F of the compressor 11 is the maximum of the operating frequency F range that can prevent the compressor 11 from being damaged by excessive temperature rise of the compressor motor (not shown). A value is stored in the storage unit 52. Further, MAX of the rotational speed N of the blower fan 13 is the largest value in the range of the rotational speed N that can prevent the blower fan 13 from being damaged by excessive temperature increase of the blower fan motor (not shown). , And is stored in the storage unit 52.

When the main control unit 51 determines that the operating frequency F of the compressor 11 is MAX and the rotation speed N of the blower fan 13 is not MAX (NO in step S103), the driving unit 53 operates the compressor 11 The frequency F and the rotational speed N of the blower fan 13 are increased (step S104).

On the other hand, when the main control unit 51 determines that the operating frequency F of the compressor 11 is MAX and the rotation speed N of the blower fan 13 is MAX (YES in step S103), the main control unit 51 is stored in the storage unit 52. The target subcooling degree SCm is increased, and the drive unit 53 reduces the opening degree Sj of the expansion device 22 so that the subcooling degree SC becomes the target subcooling degree SCm (step S105). By doing so, the blowout temperature Tout of the indoor unit 20 rises.

The conventional air conditioner performs control to increase the operating frequency F of the compressor 11 and the rotational speed N of the blower fan 13 when the set temperature Ts is higher than the blowout temperature Tout during heating operation. At the same time, the target supercooling degree SCm stored in the storage unit 52 is lowered to increase the opening degree Sj of the expansion device 22 so that the subcooling degree SC becomes the target supercooling degree SCm. By doing so, the blowout temperature Tout of the indoor unit 20 is raised, and the blowout temperature Tout is controlled to the set temperature Ts.

However, in the conventional air conditioner, the operating frequency F of the compressor 11 and the rotational speed N of the blower fan 13 become MAX under low temperature conditions where the temperature of the air taken in by the indoor unit 20 falls below 0 ° C. Also, the blowout temperature Tout did not reach the set temperature Ts, and the blowout temperature Tout could not be controlled to the set temperature Ts.

Therefore, in the air conditioner 100 according to the present embodiment, the operating frequency of the compressor 11 when the condensation temperature Tc is less than the target condensation temperature Tcm when the set temperature Ts is higher than the blowout temperature Tout during heating operation. When F is MAX, the target subcooling degree SCm stored in the storage unit 52 is increased, and the opening degree Sj of the expansion device 22 is decreased so that the subcooling degree SC becomes the target subcooling degree SCm. . By doing so, the blowout temperature Tout can be raised, and the blowout temperature Tout can reach the set temperature Ts. As a result, the air conditioning apparatus 100 according to the present embodiment can improve the heating capacity under low temperature conditions.

Here, in the air conditioning apparatus 100 according to the present embodiment, the control of the degree of supercooling SC is changed depending on whether the condensing temperature Tc is equal to or higher than the target condensing temperature Tcm or less than the target condensing temperature Tcm. This is to prevent damage to the compressor 11 due to excessive temperature rise of the compressor motor. As described above, when the condensation temperature Tc is less than the target condensation temperature Tcm, the operation frequency F of the compressor 11 needs to be increased in order to bring the condensation temperature Tc closer to the target condensation temperature Tcm. If MAX exceeds MAX, the compressor 11 may be damaged due to excessive temperature rise of the compressor motor. Therefore, when the operating frequency F of the compressor 11 reaches MAX, the condensing temperature Tc is reduced to the target condensing temperature Tcm by decreasing the opening degree Sj of the expansion device 22 so that the degree of subcooling SC becomes the target degree of subcooling SCm. Can be closer to As a result, even if the operating frequency F of the compressor 11 becomes MAX, the condensing temperature Tc can be set to the target condensing temperature Tcm. Therefore, damage to the compressor 11 due to excessive temperature increase of the compressor motor can be prevented. Can bring out the heating capacity of

As described above, in the air conditioner 100 according to the present embodiment, the compressor 11, the first heat exchanger 21, the expansion device 22, and the second heat exchanger 12 are sequentially connected by the refrigerant pipe, and a refrigerant circuit in which the refrigerant circulates And 200, and a control device 50 for controlling the compressor 11 and the expansion device 22. Further, when the set temperature Ts is higher than the blowout temperature Tout during the heating operation, the control device 50 determines whether the condensation temperature Tc is equal to or higher than the preset target condensation temperature Tcm or lower than the target condensation temperature Tcm. , Control of the degree of subcooling SC.

In addition, when the set temperature Ts is higher than the blowout temperature Tout during heating operation, the controller 50 reduces the pressure when the condensation temperature Tc is less than the target condensation temperature Tcm and when the operating frequency F of the compressor 11 is MAX. The opening degree Sj of the device 22 is increased to decrease the subcooling degree SC.

According to the air conditioner 100 of the present embodiment, when the set temperature Ts is higher than the blowout temperature Tout during the heating operation, the condensation temperature Tc is equal to or higher than the preset target condensation temperature Tcm, and the target condensation The control of the degree of subcooling SC is changed when the temperature is less than Tcm. When the condensation temperature Tc is less than the target condensation temperature Tcm, and when the operating frequency F of the compressor 11 is MAX, the degree of opening Sj of the expansion device 22 is decreased to increase the degree of subcooling SC. By so doing, the blowout temperature Tout can be raised, and the blowout temperature Tout can reach the set temperature Ts, so the heating capacity under low temperature conditions can be improved.

In addition, although the air conditioning apparatus 100 which concerns on this Embodiment becomes a structure which can perform only heating operation, it is not limited to it, for example, provides flow-path switching means, such as a four-way valve, and can also perform cooling operation. It is good also as composition.

In addition, although the outdoor unit 10 is configured to include the blower fan 13, the configuration is not limited thereto, and the configuration may not include the blower fan 13. In that case, in the processing of steps S102 to S104 in FIG. 3, the control and conditions relating to the blower fan 13 are excluded.

Further, the air conditioning apparatus 100 may include a plurality of indoor units 20 in parallel to the outdoor unit 10. In that case, the control device 50 performs the same control on each throttling device 22 of each indoor unit 20 at the same time.

Reference Signs List 10 outdoor unit, 11 compressor, 12 second heat exchanger, 13 air blowing fan, 14 discharge pressure detection device, 20 indoor unit, 21 first heat exchanger, 22 expansion device, 23 first temperature detection device, 24 second Temperature detection device, 50 control device, 51 main control unit, 52 storage unit, 53 drive unit, 100 air conditioner, 200 refrigerant circuit.

Claims (4)

A refrigerant circuit in which a compressor, a first heat exchanger, a throttling device, and a second heat exchanger are sequentially connected by a refrigerant pipe, and the refrigerant circulates;
An air conditioner comprising a control device for controlling the compressor and the expansion device and capable of heating operation,
The controller is
If the set temperature is higher than the blowing temperature during heating operation,
An air conditioner, which changes control of the degree of supercooling depending on whether the condensing temperature is equal to or higher than a preset target condensing temperature or lower than the target condensing temperature. The controller is
If the set temperature is higher than the blowing temperature during heating operation,
If the condensation temperature is less than the target condensation temperature, and if the operating frequency of the compressor is a preset MAX,
The air conditioner according to claim 1, wherein the degree of opening of the expansion device is reduced to increase the degree of subcooling. The controller is
If the set temperature is higher than the blowing temperature during heating operation,
If the condensation temperature is less than the target condensation temperature, and if the operating frequency of the compressor is less than a preset MAX:
The air conditioner according to claim 1, wherein the operating frequency of the compressor is increased. The controller is
If the set temperature is higher than the blowing temperature during heating operation,
If the condensation temperature is above the target condensation temperature,
The air conditioner according to any one of claims 1 to 3, wherein the degree of opening of the expansion device is increased to reduce the degree of subcooling.

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