KR20160028400A - Air conditioner and control method thereof - Google Patents

Abstract

One aspect of the present invention relates to an air conditioner and a control method thereof for suppressing a sudden flow of refrigerant stored in a refrigerant storage portion into a main refrigerant circuit when a type of operation is switched.
An air conditioner according to an embodiment of the present invention includes a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; Wherein the control unit determines the supercooled state or the gas-liquid two-phase state at the outlet of the condenser and determines the amount of refrigerant in the refrigerant circuit based on at least one of the temperature and the pressure detected in the refrigerant circuit, A refrigerant amount detecting device for calculating a ratio; And a control unit for controlling the refrigerant circuit according to a refrigerant amount ratio calculated by the refrigerant amount detection apparatus.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an air conditioner,

The present invention relates to an air conditioner for detecting the amount of refrigerant.

There is an air conditioner having a main refrigerant circuit in which a compressor, a four-way switching valve, an outdoor heat exchanger, a main pressure reducing valve and an indoor heat exchanger are connected in order, or a refrigerant cycle in which a refrigerant circulates. The conventional air conditioner performs the air conditioning operation such as the cooling operation and the heating operation by switching the circulation direction of the refrigerant by the four-way switching valve.

However, since the outdoor heat exchanger and the indoor heat exchanger have different volumes, the air conditioner differs in the amount of refrigerant required for the main refrigerant circuit depending on the type of air conditioning operation. Therefore, in order to improve the system efficiency, it is preferable that the air conditioner is operated at an optimal amount of refrigerant according to each operation type.

To this end, the air conditioner has a refrigerant storage portion for storing surplus refrigerant. Here, the air conditioner having the refrigerant storage part stores the surplus refrigerant in the refrigerant storage part when performing an operation with a small amount of refrigerant required for the main refrigerant circuit. Further, the air conditioner supplies the refrigerant stored in the refrigerant storage portion to the main refrigerant circuit when performing an operation requiring a large amount of refrigerant necessary for the main refrigerant circuit.

Patent Document 1 discloses a refrigeration system device having a compressor, a condenser, and an evaporator, and a receiver tank between a condenser and an evaporator. Patent Document 1 discloses that surplus refrigerant is collected in a receiver tank and refrigerant is discharged from a receiver tank in a refrigeration cycle in accordance with the operation state of the refrigerating system device.

Patent Document 1: JP-A-10-89780

One aspect of the present invention relates to an air conditioner and a control method thereof for suppressing a sudden flow of refrigerant stored in a refrigerant storage portion into a main refrigerant circuit when a type of operation is switched.

An air conditioner according to an embodiment of the present invention includes a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator; Wherein the control unit determines the supercooled state or the gas-liquid two-phase state at the outlet of the condenser and determines the amount of refrigerant in the refrigerant circuit based on at least one of the temperature and the pressure detected in the refrigerant circuit, A refrigerant amount detecting device for calculating a ratio; And a control unit for controlling the refrigerant circuit according to a refrigerant amount ratio calculated by the refrigerant amount detection apparatus.

The refrigerant amount detection device can calculate an average value of the refrigerant amount ratios based on the calculated refrigerant amount ratio.

Wherein the refrigerant circuit comprises: a first temperature sensor for detecting a first refrigerant temperature at an outlet of the condenser; And a second temperature sensor for detecting a second refrigerant temperature on the downstream side of the fluid resistance provided on the outlet side of the condenser, wherein the refrigerant amount detection device detects the refrigerant temperature based on the first refrigerant temperature and the second refrigerant temperature , The supercooled state or the vapor-liquid two-phase state can be judged.

The refrigerant circuit may further include a subcooler positioned between the condenser and the expansion valve and cooling the liquid refrigerant generated in the condenser.

The control unit may control at least one of the compressor, the condenser, the expansion valve, the evaporator, and the subcooler to operate constantly under the control of the refrigerant amount detecting apparatus.

The refrigerant circuit includes a refrigerant storage container for storing charged refrigerant; And a refrigerant injection valve for controlling the refrigerant supplied from the refrigerant storage container, wherein when the refrigerant is charged, the controller controls the refrigerant injection valve when the average value of the refrigerant amount ratio reaches 100% .

Wherein the refrigerant circuit comprises: a receiver for storing surplus refrigerant present in the refrigerant circuit in a supercooled liquid state; And a flow controller for reducing the pressure of the refrigerant flowing out of the receiver and adjusting the flow rate of the refrigerant.

The refrigerant may comprise a non-azeotropic refrigerant comprising R32 and HFO1234yf or HFO1234ze.

The non-azeotropic mixed refrigerant may be characterized in that the content of HFC is less than 70% by weight, the content of HFO1234yf or HFO1234ze is less than 30% by weight, and the balance is natural refrigerant.

The volume of the receiver may be the same as the volume of the refrigerant circuit in which the refrigerant amount obtained by subtracting the refrigerant amount during the cooling operation from the refrigerant amount during the heating operation is converted into the supercooled liquid state.

The refrigerant circuit may further include a main coolant condensed in the evaporator or the condenser and a supercooler that is subcooled in the main coolant and undergoes heat exchange with the decompressed refrigerant decompressed by the supercooling reducing valve, have.

The receiver may further include at least one refrigerant amount detecting mechanism for detecting an amount of refrigerant in the receiver.

And an auxiliary unit connected to the indoor unit including the compressor and the condenser and the indoor unit including the evaporator, the auxiliary unit being detachable from the refrigerant circuit piping and including the refrigerant amount detection device.

The auxiliary unit may further include a refrigerant injection valve for adjusting the refrigerant pipe of the auxiliary unit when the calculated refrigerant amount ratio reaches 100% when the refrigerant is filled in the refrigerant circuit.

The auxiliary unit includes a refrigerant storage container for storing charged refrigerant; And a refrigerant injection valve for controlling the refrigerant supplied from the refrigerant storage container, wherein when the refrigerant is charged, the controller controls the refrigerant injection valve when the average value of the refrigerant amount ratio reaches 100% .

The auxiliary unit may further include an auxiliary heat exchanger that performs heat exchange with the external heat source device except for the air conditioner.

Wherein the auxiliary unit comprises: a receiver for storing the surplus refrigerant present in the piping of the auxiliary unit in a supercooled liquid state; And a flow rate adjusting unit for reducing the pressure of the refrigerant flowing out of the receiver and adjusting the flow rate of the refrigerant.

In the control method of an air conditioner including a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator according to an embodiment of the present invention, it is determined whether or not the refrigerant state at the outlet of the condenser is a supercooled state or a gas- and; Calculating a refrigerant amount ratio in the refrigerant circuit based on at least one of a temperature and a pressure detected in the refrigerant circuit and a predetermined value according to the refrigerant state; And controlling the refrigerant circuit according to the calculated refrigerant amount ratio.

The control method of the air conditioner may further include calculating an average value of the refrigerant amount ratios based on the calculated refrigerant amount ratios.

According to the air conditioner and the control method thereof, when the type of operation is switched, the refrigerant stored in the refrigerant storage portion can be prevented from flowing rapidly into the main refrigerant circuit.

1 is a schematic diagram showing a configuration of an air conditioner in a first embodiment.
Fig. 2 is a schematic block diagram showing the configuration of the refrigerant quantity detection device in the first embodiment. Fig.
3 is a schematic block diagram showing the configuration of the air conditioner according to the second embodiment.
Fig. 4 is a schematic block diagram showing the configuration of a refrigerant amount detection device according to the second embodiment. Fig.
5 is a flowchart showing an example of the operation of the refrigerant amount detection device according to the second embodiment.
6 is a schematic block diagram showing the configuration of the air conditioner according to the third embodiment.
7 is a schematic block diagram showing the configuration of a refrigerant amount detection device according to the third embodiment.
8 is a flowchart showing an example of the operation of the refrigerant amount detection device according to the third embodiment.
9 is a schematic block diagram showing a configuration of an air conditioner according to a fourth embodiment.
10 is a schematic block diagram showing the configuration of a conventional air conditioner.
11 is a pressure-specific enthalpy diagram of the air conditioner during the cooling operation.
12 is a diagram showing the relationship between the opening and closing of the connection opening / closing valve of the fourth embodiment and the refrigerant temperature discharged from the compressor.
Fig. 13 is a flowchart showing a procedure of opening and closing control of a connection opening / closing valve executed by the control unit of the fourth embodiment.
14 is a schematic block diagram showing the configuration of an air conditioner according to a fifth embodiment.
15 is a view showing a configuration in the vicinity of the supercooler of the fifth embodiment.
16 is a pressure-specific enthalpy diagram of the air conditioner of the fifth embodiment.
17A and 17B are views showing the relationship between the coolant temperature flowing through the first pipe and the coolant temperature flowing through the second pipe in the supercooler.
18 is a diagram showing a procedure of opening control of a supercooling reducing valve controlled by the control unit of the fifth embodiment.
19 is a diagram showing the relationship between the opening degree of the supercooling reducing valve, the amount of refrigerant sucked into the compressor, and the system efficiency of the air conditioner.
20 is a schematic block diagram showing the configuration of the air conditioner according to the sixth embodiment.
21 is a view showing a refrigerant amount detecting mechanism of the sixth embodiment.
22 is a view showing a modified example of the refrigerant amount detecting mechanism.
23 is a schematic diagram showing the configuration of an air conditioner and an auxiliary unit in the seventh embodiment.
24 is a schematic block diagram showing the configuration of the refrigerant quantity detection device in the seventh embodiment.
Fig. 25 is a schematic block diagram showing the configuration of an air conditioner and an auxiliary unit in the eighth embodiment. Fig.
26 is a schematic block diagram showing a configuration of a refrigerant quantity detection device according to the eighth embodiment.
27 is a schematic block diagram showing the configuration of an air conditioner and an auxiliary unit according to a ninth embodiment.
28 is a view showing a refrigerant amount detecting mechanism of the ninth embodiment.
29 is a schematic view showing the configuration of an air conditioner and an auxiliary unit in the tenth embodiment.
30 is a schematic view showing the type of the heater and the configuration of the auxiliary heat exchanger for heating the refrigerant.
31 is a schematic diagram showing a modified example of the auxiliary unit.
32 is a schematic diagram showing a modified example of the auxiliary unit.
33 is a schematic view showing a configuration of an air conditioner and an auxiliary unit in the eleventh embodiment.
34 is a view showing the flow of refrigerant during the normal cooling operation according to the eleventh embodiment.
35 is a view showing the flow of refrigerant when the outdoor air temperature is low according to the eleventh embodiment.
36 is a view showing the flow of the refrigerant during the heating operation of the eleventh embodiment.

≪ First Embodiment >

A first embodiment of the present invention will be described with reference to the drawings.

1, the air conditioner 100 of the first embodiment includes: an outdoor unit 10 installed outdoors of a building; An indoor unit (11) installed in the building; A refrigerant circuit (20) configured by connecting an outdoor unit (10) and an indoor unit (11) with a refrigerant pipe; An air conditioner controller 30 for controlling the outdoor unit 10 and the indoor unit 11 to perform an air conditioning operation; And a refrigerant quantity detecting device (40) for detecting the refrigerant quantity in the refrigerant circuit. On the other hand, an air conditioner 100 that performs a cooling operation will be described below.

The refrigerant circuit 20 is constituted by connecting a compressor 201, a four-way switching valve 202, a condenser (outdoor heat exchanger) 203, a first expansion valve 204 and an evaporator (indoor heat exchanger) . In this embodiment, the compressor 201, the four-way switching valve 202, the condenser 203, and the first expansion valve 204 are installed inside the outdoor unit 10 and the evaporator 205 is connected to the indoor unit 11, As shown in Fig. On the other hand, the outdoor unit 10 compresses the refrigerant vaporized in the evaporator 205 in the indoor unit 11 and cools it. Further, the indoor unit 11 performs heat exchange between the room air and the refrigerant in the evaporator 205, cools the room air, and evaporates the refrigerant.

The compressor (201) compresses the vaporized refrigerant gas introduced at the inlet of the low pressure side to generate a high temperature and high pressure compressed gas. The compressor 201 is driven by a motor capable of controlling the rotation speed, and the compression ability is changed in accordance with the rotation speed of the motor. That is, the compression capability is high when the rotation speed of the motor is high, and the compression ability is low when the rotation speed of the motor is low. The compressor 201 controls the rotational speed of the motor by a compressor control unit 301, which will be described later. The compressor 201 sends the generated high-temperature and high-pressure compressed gas to the condenser 203 through the four-way switching valve 202.

The condenser 203 condenses the compressed gas generated by the compressor 201 through a heat exchanger. The condenser 203 performs heat exchange between the high temperature compressed gas and the low temperature outdoor air, and generates liquid refrigerant. Then, the condenser 203 delivers the liquid refrigerant generated by the heat exchange to the first expansion valve 204.

The first expansion valve (204) is a valve that adjusts a flow rate flowing through the first expansion valve (204) by opening and closing. Here, the first expansion valve (204) is opened / closed by the first expansion valve control section (302). By opening the first expansion valve (204), the liquid refrigerant expands and vaporizes to become refrigerant gas. This refrigerant gas is lower in temperature than the liquid refrigerant before it flows into the first expansion valve (204). The first expansion valve 204 controls the degree of opening (degree of opening) indicating the degree of opening according to a signal output from the first expansion valve control section 302, which will be described later. Then, the first expansion valve (204) delivers the refrigerant gas to the evaporator (205).

The evaporator 205 performs heat exchange between the refrigerant gas generated by the first expansion valve 204 and the room air at a high temperature. The evaporator 205 cools the room air and vaporizes part of the refrigerant. The gas-liquid two-phase refrigerant generated in the evaporator 205 is sent to the compressor 201 through the four-way switching valve 202. The gas-liquid two-phase refrigerant means two states of gas and liquid.

In addition, the outdoor unit fan 10F is installed in the outdoor unit 10 and the indoor unit fan 11F is installed in the indoor unit 11. [

The outdoor fan (10F) blows to the condenser (203) to cool the refrigerant. The outdoor fan 10F is controlled by the outdoor fan control unit 303, which will be described later.

The indoor fan (11F) cools the room air in the evaporator (205) and blows the cooled air into the room. The indoor fan 11F is controlled by the indoor fan control unit 304, which will be described later.

A discharge temperature sensor 206, an intake temperature sensor 207, an outlet temperature sensor 208, a liquid pipe temperature sensor 209, a high pressure sensor 210, and a low pressure sensor 211 are connected to the refrigerant circuit 20 Is installed.

The discharge temperature sensor 206 detects the refrigerant temperature (discharge temperature Td) at the high pressure side of the compressor 201 and outputs a signal indicating the detected discharge temperature to the A / D converter 50.

The suction temperature sensor 207 detects the refrigerant temperature (suction temperature Tsuc) at the low-pressure side of the compressor 201 and outputs a signal indicating the detected suction temperature to the A / D converter 50. [

The outlet temperature sensor 208 detects the refrigerant temperature (outlet temperature Tcond (first refrigerant temperature)) at the outlet of the condenser 203 and outputs a signal indicating the detected outlet temperature to the A / D converter 50 do. On the other hand, the outlet temperature sensor 208 is installed in the heat transfer pipe on the outlet side of the condenser 203.

The liquid pipe temperature sensor 209 detects the refrigerant temperature (liquid pipe temperature Tsub (second refrigerant temperature)) on the downstream side of the first expansion valve 204 installed on the outlet side of the condenser 203, To the A / D converter 50. The A / On the other hand, the liquid pipe temperature sensor 209 is provided in the liquid pipe 212. The liquid pipe 212 is a pipe connecting the outlet of the condenser 203 and the inlet of the evaporator 205.

The high pressure sensor 210 detects the pressure (high pressure side pressure Pd) on the high pressure side of the compressor 201 and outputs a signal indicating the detected high pressure side pressure to the A / D conversion section 50.

The low pressure sensor 211 detects the pressure on the low pressure side of the compressor 201 (low pressure side pressure Ps) and outputs a signal indicating the detected low pressure side pressure to the A / D converter 50.

The air conditioner control unit 30 controls each component of the air conditioner 100. On the other hand, although the air conditioner control unit 30 is connected to the components of the indoor unit 11 and the outdoor unit 10, the description of the connection is omitted in Fig. The details of the air conditioner control unit 30 will be described later with reference to Fig.

The refrigerant amount detection device (40) detects the amount of refrigerant in the refrigerant circuit in the air conditioner (100). On the other hand, although the refrigerant quantity detecting device 40 is connected to the components of the indoor unit 11 and the outdoor unit 10, the description of the connection is omitted in Fig. Details of the refrigerant amount detection device 40 will be described later with reference to Fig.

2 is a schematic block diagram showing the configuration of the refrigerant amount detection device 40 according to the present embodiment. On the other hand, the A / D converter 50 analog-to-digital converts the signals received from the sensors 206 to 211, and outputs the converted signals to the refrigerant amount detecting unit 41. [ The input unit 60 outputs, to the control unit 411, detection start information or the like indicating that the detection of the refrigerant amount is started, based on the operation of the user. The display unit 70 is a display unit for displaying information such as a digital display panel by LED, for example, and displays information on the refrigerant amount ratio inputted from the refrigerant amount averaging unit 414 described later.

Specifically, the refrigerant amount detection device 40 includes a refrigerant amount detection part 41 for determining the refrigerant state, a refrigerant amount detection part 41 for calculating the refrigerant amount ratio, a storage part 42 for storing the parameters used for calculating the refrigerant amount ratio and the previously calculated refrigerant amount ratio, Respectively.

The refrigerant amount detection unit 41 calculates the refrigerant amount ratio based on the information of the temperature and the pressure inputted from the A / D conversion unit 50, and outputs the calculated information on the refrigerant amount ratio to the display unit 70. [ Here, the refrigerant amount ratio is a value ("actual refrigerant amount" / "prescribed refrigerant amount") obtained by dividing the amount of refrigerant actually in the air conditioner 100 by the amount of refrigerant specified as the specification for the air conditioner 100.

The refrigerant amount detection unit 41 includes a control unit 411, a refrigerant state acquisition unit 412, a refrigerant amount calculation unit 413, and a refrigerant amount average calculation unit 414.

The control unit 411 receives detection start information indicating that the detection of the refrigerant amount ratio of the air conditioner 100 is to be started from the input unit 60. [ Further, the control unit 411 outputs to the air conditioner control unit 30 an instruction to perform the operation in the predetermined operation mode which is the cooling operation. The control unit 411 outputs an operation termination command for terminating the operation to the air conditioner control unit 30. [

On the other hand, the air conditioner control unit 30 includes a compressor control unit 301 for controlling the rotation speed of the motor of the compressor 201 based on a command input from the control unit 411; A first expansion valve control section (302) for controlling the opening degree of the first expansion valve (204); An outdoor fan control unit 303 for controlling the rotating speed of the outdoor fan 10F; And an indoor fan control unit 304 for controlling the rotating speed of the indoor fan 11F.

More specifically, the air conditioner control unit 30 controls the superheating degree SH of the evaporator 205 provided in the indoor unit 11 to be constant (for example, 3K). The superheat degree is obtained by subtracting the saturation temperature at the evaporation temperature from the refrigerant temperature at the outlet of the evaporator 205, that is, subtracting the saturation temperature at the low pressure side of the compressor 201 from the refrigerant temperature at the low pressure side of the compressor 201 will be. The first expansion valve control unit 302 controls the degree of superheat of the evaporator 205 to be constant by adjusting the opening degree of the first expansion valve 204.

The control unit 411 also outputs to the compressor control unit 301 a command to operate the rotation speed of the motor of the compressor 201 at a predetermined rotation speed (for example, 65 Hz). The compressor control unit 301 receives a command from the control unit 411 to cause the motor 201 to rotate at a predetermined rotational speed (for example, 65 Hz) Hz.

The control unit 411 outputs to the outdoor fan control unit 303 an instruction to cause the outdoor fan 10F to operate at a constant speed. The outdoor fan control unit 303 causes the outdoor fan 10F to operate at a constant speed.

The control unit 411 outputs to the indoor fan control unit 304 a command to control the indoor fan 11F at a constant speed. The indoor fan control unit 304 causes the indoor fan 11F to operate at a constant speed.

Further, the control unit 411 outputs a command to the refrigerant state acquisition unit 412 and the refrigerant amount calculation unit 413 to calculate the refrigerant amount ratio. The control unit 411 receives from the refrigerant amount average calculation unit 414 an average value calculation end signal indicating that the calculation of the average value of the refrigerant amount ratios is completed. The control unit 411 outputs an operation end signal to the air conditioner control unit 30 when receiving the average value calculation end signal from the refrigerant amount average calculation unit 414. [

The refrigerant state acquisition section 412 determines whether or not the refrigerant state at the outlet of the condenser 203 is the supercooled state after the air conditioner control section 30 starts the operation of the air conditioner 100 in the predetermined operation mode Liquid two-phase state. The refrigerant state acquisition section 412 determines that the refrigerant state is one of the supercooled state or the vapor-liquid two-phase state, using the outlet temperature Tcond indicated by the outlet temperature signal and the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal as parameters. Then, this discrimination signal is outputted to the refrigerant quantity calculation section 413. [

Details are as follows.

Tcond-Tsub? X, it is determined that the refrigerant state is the "supercooled state ".

When Tcond-Tsub > X, the refrigerant state is judged as "gas-liquid two-phase state ".

Here, X is a constant and is a value (for example, X = 1.5) obtained in advance using the measured data.

The refrigerant amount calculation unit 413 calculates the refrigerant amount ratio in the air conditioner 100 by using different calculation equations according to the refrigerant state acquired by the refrigerant state acquisition unit 412. [

More specifically, the coolant amount calculation unit 413 calculates the coolant amount ratio RA by using the supercooled state calculation formula when the supercooled state is in the supercooled state, and calculates the coolant amount ratio RA by using the vapor-liquid two- do.

The calculation formula for the supercooled state is as follows.

RA = a1 + b1 x Pd + c1 x Ps + d1 x Tsub + e1 x Td

Here, the constants a1, b1, c1, d1, and e1 are values obtained in advance by multiple regression calculation using the actual data showing the relationship between Pd, Ps, Tsub, Td and RA in the supercooled state. On the other hand, the constants a1, b1, c1, d1 and e1 are recorded in the calculation parameter storage section 421 set in the storage section 42. [

The equation for the vapor-liquid two-phase state is as follows.

RA = a2 + b2 x Pd + c2 x Ps + d2 x Tsub + e2 x Td

Here, the constants a2, b2, c2, d2, and e2 are values previously obtained by multiple regression calculation using the actual data showing the relationship between Pd, Ps, Tsub, Td and RA in the vapor-liquid two- On the other hand, the constants a2, b2, c2, d2, and e2 are recorded in the calculation parameter storage unit 421.

The refrigerant quantity calculation section 413 reads the constants a1, b1, c1, d1, e1 or constants a2, b2, c2, d2, e2 in accordance with the refrigerant state acquired by the refrigerant state acquisition section 412. Further, the coolant amount calculation section 413 calculates the coolant amount based on the discharge pressure Pd indicated by the discharge pressure signal and the suction pressure Ps indicated by the suction pressure signal, the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal, and the discharge temperature Td indicated by the discharge temperature signal, The refrigerant quantity ratio RA is calculated by an equation corresponding to the state. The coolant amount calculation unit 413 records the coolant amount ratio data indicating the calculated coolant amount ratio RA in the coolant amount storage unit 422 set in the storage unit 42. [

The refrigerant amount calculation unit 414 reads the refrigerant amount ratio RA calculated within a predetermined time (for example, past five minutes) from the refrigerant amount calculation unit 413. The refrigerant amount average calculation unit 414 calculates an average value of the read refrigerant amount ratio RA and outputs the calculated average value of the refrigerant amount ratio RA to the display unit 70. [ When the calculation of the average value of the refrigerant amount ratio RA ends, the refrigerant amount average calculation unit 414 outputs the calculation end signal indicating that the calculation of the average value of the refrigerant amount ratio RA is ended to the control unit 411. [

According to the air conditioner 100 constructed as described above, when the refrigerant state is the supercooled state, the calculation formula for the supercooled state is used. When the refrigerant state is the gas-liquid two-phase state, It is possible to detect the amount of the refrigerant precisely regardless of the refrigerant state at the outlet of the condenser 203. [ Therefore, the present invention can accurately detect the refrigerant amount ratio even when a long piping is used or when the installation state has a large difference between the outdoor unit 10 and the indoor unit 11.

According to the present embodiment, the control section 411 fixes the opening degree of the second expansion valve 215 at a predetermined value. Accordingly, the degree of cooling of the liquid refrigerant in the liquid pipe 212 can be made constant, and the amount of refrigerant can be detected with high precision.

Further, according to the present embodiment, the control unit 411 fixes the compression capacity of the compressor 201 to a predetermined value. Accordingly, in the present embodiment, the refrigerant state at the inlet and the outlet of the compressor 201 can be made constant, and the refrigerant amount ratio with high accuracy can be detected.

Further, according to the present embodiment, the control section 411 fixes the opening degree of the first expansion valve 204 to a predetermined value. Accordingly, in the present embodiment, the degree of cooling in the first expansion valve 204 can be made constant, and the refrigerant amount ratio can be detected with high precision.

Further, according to the present embodiment, the controller 411 fixes the rotational speed of the outdoor fan 10F and the rotational speed of the indoor fan 11F to predetermined values. Accordingly, in the present embodiment, the degree of heat exchange in the condenser 203 can be made constant, the degree of heat exchange in the evaporator 205 can be made constant, and a highly accurate refrigerant amount ratio can be detected.

≪ Second Embodiment >

Next, a second embodiment of the present invention will be described with reference to the drawings.

The configuration of the air conditioner 100 of the second embodiment is the same as the configuration of the air conditioner 100 of the first embodiment except that a subcooler 213 is newly added as shown in Fig. 3 . On the other hand, in this embodiment, the first expansion valve 204 is provided in the indoor unit 11.

Specifically, the air conditioner 100 includes a subcooler 213 installed between the condenser 203 and the first expansion valve 204; A bypass path 214 branched from the downstream side of the subcooler 213 in the refrigerant circuit 20 and connected to the low-pressure side of the compressor 201 via the subcooler 213; And a second expansion valve 215 installed in the bypass path 214 for adjusting the amount of refrigerant flowing into the subcooler 213.

The subcooler 213 cools the liquid refrigerant generated in the condenser 203 by using the subcooler cooling refrigerant sent from the second expansion valve 215. The subcooler 213 performs heat exchange between the high temperature liquid refrigerant and the low temperature subcooler cooling refrigerant. The subcooler 213 sends the cooled liquid refrigerant to the first expansion valve 204. The subcooler 213 sends the subcooler-cooled refrigerant after heat exchange to the low-pressure-side inlet of the compressor 201.

The second expansion valve 215 is a valve that adjusts a flow rate flowing through the second expansion valve 215 by opening and closing. Here, the second expansion valve 215 is controlled by the second expansion valve control unit 305 to indicate the degree of opening thereof (see Fig. 4). The liquid refrigerant generated in the evaporator 205 and introduced into the second expansion valve 215 through the subcooler 213 is expanded and vaporized by the opening of the second expansion valve 215, And becomes a sub cooler cooling refrigerant that is a refrigerant. The second expansion valve 215 sends the subcooler-cooled refrigerant to the subcooler 213.

In addition, the liquid pipe temperature sensor 209 of the present embodiment detects the refrigerant temperature (liquid pipe temperature Tsub) near the outlet of the subcooler 213, and outputs a signal indicating the detected liquid pipe temperature to A / D conversion (50). On the other hand, the liquid pipe 212 is a pipe for flowing liquid refrigerant, which is provided in the section from the outlet of the condenser 203 to the first expansion valve 204 through the subcooler 213.

Next, the operation of the refrigerant amount detection device 40 according to the present embodiment will be described with reference to Fig.

5 is a flowchart showing an example of the operation of the refrigerant amount detection device 40 according to the present embodiment.

(Step S201) The input unit 60 accepts input of information indicating start of detection of the amount of refrigerant from the user. Then, the input unit 60 outputs the detection start information for starting the detection of the refrigerant amount to the control unit 411. [ Thereafter, the flow proceeds to step S102.

(Step S102) Based on the detection start information inputted in Step S201, the control unit 411 outputs a command to start the operation of the air conditioner 100 to the air conditioner control unit 30 implementation).

On the other hand, in all the operation modes described later, the air conditioner 100 performs the cooling operation.

When the air conditioner 100 includes a plurality of indoor units 11 (only one indoor unit 11 is shown in Fig. 1), all the indoor units 11 are operated in the same manner.

Further, the control unit 411 outputs a command to the air conditioner control unit 30 to perform the initial mode operation. The air conditioner control unit 30 starts the initial mode operation. The initial mode operation means specifically performing the following operation.

The air conditioner control unit 30 blows the rotation speed of the indoor fan 11F at a rotation speed of a "rapid" mode preset in advance and having a larger amount of air than usual. The air conditioner control unit 30 controls the superheat degree of the evaporator 205 provided in the indoor unit 11 to be 3K (all indoor units SH control: SH = 3K). The first expansion valve control unit 302 controls the degree of superheat of the evaporator 205 to be 3K by adjusting the opening degree of the first expansion valve 204. [ The air conditioner control unit 30 sets the set temperature of the room temperature to 3 DEG C and operates the air conditioner 100 (all indoor unit set temperature: Remote = 3K). The air conditioner control unit 30 continues the initial mode operation, for example, for 5 to 10 minutes, and then proceeds to step S103.

(Step S103) The control unit 411 outputs a command to the air conditioner control unit 30 to perform the normal mode operation. The air conditioner control unit 30 starts the normal mode operation. The normal mode operation means specifically performing the following operation.

The control unit 411 outputs a command to the compressor control unit 301 to make the rotation speed of the motor of the compressor 201 run at a predetermined rotation speed (for example, 65 Hz) (compressor 65 Hz Fixed). The compressor control unit 301 receives a command from the control unit 411 to cause the motor 201 to rotate at a predetermined rotational speed (for example, 65 Hz) Hz.

The control unit 411 outputs a command to the first expansion valve control unit 302 to control the opening degree to a predetermined value (for example, 120 pls). Here, pls used as the unit of opening of the expansion valve is defined to be "0" pls when fully closed and "2000" pls when fully opened. The first expansion valve control unit 302 receives a command to control the opening degree to 120 pls from the control unit 411 and operates the opening degree of the first expansion valve 204 to 120 pls (EEV: 120 pls Fixed).

The control unit 411 outputs a command to the second expansion valve control unit 305 to control the opening degree to a predetermined value (for example, 120 pls). The second expansion valve control unit 305 receives an instruction to control the opening degree to 120 pls and operates the opening degree of the second expansion valve 215 to 120 pls (EVI: 120 pls Fixed) from the control unit 411. [ The control unit 30 continues the normal mode operation, for example, for five minutes, and then proceeds to step S104.

(Step S104) The control unit 411 outputs a command to the air conditioner control unit 30 to perform the measurement mode operation. The air conditioner control unit 30 starts the measurement mode operation. Specifically, the measurement mode operation means performing the following operation.

The control unit 411 outputs a command to the outdoor fan control unit 303 to measure the outdoor fan 10F at a constant speed. The indoor fan control unit 304 drives the outdoor fan 10F at a constant speed (outdoor fan: Step Fixed). After the measurement mode operation is continued for, for example, 25 minutes, the flow proceeds to step S105.

(Step S105) The control unit 411 outputs a command to the refrigerant state acquisition unit 412 and the refrigerant amount calculation unit 413 to calculate the refrigerant amount ratio. The refrigerant state acquisition section 412 receives the outlet temperature signal and the liquid pipe temperature signal. The refrigerant amount calculation section 413 receives the discharge temperature signal, the liquid pipe temperature signal, the high-pressure-side pressure signal, and the low-pressure-side pressure signal. Thereafter, the process proceeds to step S106.

(Step S106) The refrigerant state acquisition section 412 determines whether the supercooled state or the gas-liquid two-phase state is determined based on the outlet temperature Tcond indicated by the outlet temperature signal input in step S105 and the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal do.

The refrigerant amount calculation unit 413 reads the calculation formula (calculation formula parameter) according to the refrigerant state obtained by the refrigerant state acquisition unit 412 from the calculation parameter storage unit 421. [ The coolant amount calculation section 413 calculates the coolant amount calculation section 413 based on the high pressure side pressure Pd indicated by the high pressure side pressure signal, the low pressure side pressure Ps indicated by the low pressure side pressure signal, the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal, Based on the temperature Td, the refrigerant amount ratio RA is calculated by an equation that is matched to the refrigerant state (refrigerant amount detecting step). The refrigerant amount calculation section 413 records the calculated RA in the refrigerant amount storage section 422. [ Thereafter, the flow proceeds to step S107.

(Step S107) The control unit 411 determines whether or not five minutes have elapsed since the start of the command to calculate the refrigerant amount ratio. If it is determined that 5 minutes have elapsed (Yes), the process proceeds to step S108. If it is not determined that 5 minutes have elapsed (No), the flow returns to step S105.

(Step S108) The refrigerant amount calculation section 414 reads the refrigerant amount ratio recorded in the refrigerant amount storage section 422 in step S106, and calculates the average value of the refrigerant amount ratios. The refrigerant amount averaging unit 414 outputs information on the average value of the calculated refrigerant amount ratios to the display unit 70. [ The refrigerant amount calculation unit 414 outputs the average value calculation end information indicating that the average value of the refrigerant amount ratios has been completed to the control unit 411. [ Thereafter, the flow proceeds to step S109.

(Step S109) The display unit 70 receives and displays information indicating the average value of the refrigerant amount ratios calculated by the refrigerant amount averaging calculation unit 414 in step S108. The control unit 411 outputs an operation stop instruction of the air conditioner 100 to the air conditioner control unit 30 based on the average value calculation end information inputted from the refrigerant amount average calculation unit 414 in step S108. The air conditioner control unit 30 stops the operation of the air conditioner 100 based on the operation stop signal inputted from the control unit 411. [ Thereafter, the process proceeds to the termination process.

As described above, according to the present embodiment, when the refrigerant state is the supercooled state, the calculation formula for the supercooled state is used, and when the refrigerant state is the vapor-liquid two-phase state, The amount of refrigerant can be accurately detected regardless of the refrigerant state at the outlet. The refrigerant amount ratio can be accurately detected even when a long pipe using the subcooler 213 is used to prevent vaporization in the liquid pipe or when there is a large difference between the outdoor unit 10 and the indoor unit 11. [

≪ Third Embodiment >

Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

In the first and second embodiments, the amount of the refrigerant in the air conditioner 100 can be accurately measured. In the present embodiment, when the refrigerant is supplemented, the refrigerant amount ratio is calculated, When the refrigerant amount ratio reaches 100%, a display prompting the operator to perform the operation of the refrigerant injection valve 216 is performed.

6 is a schematic block diagram showing the configuration of the air conditioner 100 according to the third embodiment.

The configuration of the air conditioner 100 of the present embodiment is similar to that of the air conditioner 100 of the second embodiment except that a refrigerant injection valve (charge valve) 216 and a refrigerant storage container 217 are newly added. (Fig. 3). Therefore, description of the refrigerant injection valve 216 and the refrigerant storage container 217 will be omitted.

The refrigerant injection valve 216 is a valve that is opened and closed by the person performing the operation in order to supplement the refrigerant in accordance with an instruction to be displayed on the display unit 70.

The refrigerant storage container 217 is a container for storing the refrigerant to be replenished.

7 is a schematic block diagram showing the configuration of the refrigerant amount detection device 40 according to the present embodiment.

The configuration of the refrigerant quantity detection device 40 of the present embodiment is the same as the configuration of the refrigerant quantity detection device 40 except that the refrigerant quantity determination section 415 is newly added and the second function is added to the refrigerant quantity averaging section 414 and the control section 411, (FIG. 4) of the refrigerant amount detection device 40 in the embodiment. Therefore, explanations of the refrigerant amount calculation section 414, the refrigerant amount determination section 415, and the control section 411 will be omitted.

The coolant amount average calculation section 414 reads the coolant amount ratio calculated from the coolant amount storage section 422 within a predetermined time (for example, past five minutes). The refrigerant amount calculation section 414 calculates the moving average value of the read refrigerant amount ratio and outputs the calculated moving average value to the refrigerant amount determination section 415. [

The refrigerant amount determining section 415 determines whether or not the moving average value of the refrigerant amount ratio exceeds 100% based on the moving average value of the refrigerant amount ratio inputted from the refrigerant amount averaging calculation section 414. When the refrigerant amount determining section 415 determines that the moving average value of the refrigerant amount ratio exceeds 100%, the refrigerant amount determining section 415 outputs a charging end signal to the control section 411. [

The control unit 411 causes the display unit 70 to open the refrigerant injection valve 216 on the basis of the input of the detection start information from the input unit 60 and the input of the charge end signal from the refrigerant amount determination unit 415 Quot ;, "close ", or" close "

Next, the operation of the refrigerant amount detection device 40 according to the present embodiment will be described with reference to Fig. 8 is a flowchart showing an example of the operation of the refrigerant amount detection device 40 according to the present embodiment.

(Step S201) The input unit 60 receives the input to start automatic charging of the amount of refrigerant from the user, and outputs detection start information for starting detection of the amount of refrigerant to the control unit 411. [ Thereafter, the flow proceeds to step S202.

(Step S202) The control unit 411 outputs to the display unit 70 a command to perform a display for instructing the person who performs the operation so as to close the refrigerant injection valve 216. [ Thereafter, the flow proceeds to step S203. The processes in steps 203 to 205 are the same as those in steps S102 to S104 in the second embodiment (FIG. 5).

(Step S206) The control unit 411 outputs to the display unit 70 a command to perform an instruction to instruct the person who performs the operation to open the refrigerant injection valve 216. [ Thereafter, the flow proceeds to step S207. The processes in steps S207 and 208 are the same as those in steps S105 and 106 in the second embodiment (FIG. 5).

(Step S209) The coolant amount calculation section 414 reads the coolant amount ratio recorded in the coolant amount storage section 422, and calculates a moving average value of the coolant amount ratio, for example, for 5 minutes. The refrigerant amount averaging unit 414 outputs information on the moving average value of the calculated refrigerant amount ratio to the refrigerant amount determining unit 415. [ Thereafter, the flow proceeds to step S210.

(Step S210) The refrigerant amount determining section 415 determines whether or not the moving average value of the refrigerant amount ratio is equal to or more than 100%, based on the information on the moving average value of the refrigerant amount ratio input from the refrigerant amount averaging section 414. If it is determined that the moving average value is equal to or more than 100% (Yes), the coolant amount determining section 415 outputs the charge end signal indicating that the coolant has been completely charged to the control section 411, and then proceeds to step S211. If it is determined that the moving average value is less than 100% (No), the process proceeds to step S207.

(Step S211) The control unit 411 outputs to the display unit 70 a command to perform a display for instructing the person performing the operation so as to close the refrigerant injection valve 216. [ The control unit 411 outputs an operation stop instruction of the air conditioner 100 to the air conditioner control unit 30 based on the charge end signal inputted from the refrigerant amount determination unit 415 in step S210. The air conditioner control unit 30 stops the operation of the air conditioner 100 based on the operation stop signal inputted from the control unit 411. [ And outputs an operation stop instruction of the air conditioner (100) to the air conditioner control unit (30). The air conditioner control unit 30 stops the operation of the air conditioner 100 based on the operation stop signal inputted from the control unit 411. [ Thereafter, the process proceeds to the termination process.

As described above, according to the present embodiment, the air conditioner 100 is provided with the refrigerant injection valve 216 for filling the air conditioner 100 with the refrigerant. In accordance with the judgment of the refrigerant amount determination section 415, An instruction to close the valve 216 is displayed on the display unit 70. [ Accordingly, in the present embodiment, when the detection of the refrigerant amount ratio is started to the person performing the operation, the refrigerant injection valve 216 is opened, and when the refrigerant amount ratio becomes 100% or more, the refrigerant injection valve 216 So that the refrigerant can be replenished reliably.

In the present embodiment, the refrigerant injection valve 216 is opened and closed by a person who performs the operation, but the control unit 411 controls the refrigerant injection valve 216 through the air conditioner control unit 30 , It may be automatically opened and closed.

On the other hand, in each of the above-described embodiments, the reliability of the compressor 201 continues to be protected. In the case of entering the protection zone (each measured value of the discharge temperature, overcurrent, high pressure and low pressure is the minimum physical quantity causing a predetermined reaction The operation of the air conditioner 100 may be stopped, and the "detection failure" may be displayed on the display unit 70. [

In addition, the following equations are also used as calculation formulas for calculating the refrigerant amount ratios in the above-described respective embodiments, and they are also free.

RA = f (Tc, Te, Tsub, Td)

That is, the calculation formula for the supercooled state is as follows.

RA = a3 + b3 x Tc + c3 x Te + d3 x Tsub + e3 x Td

Here, the constants a3, b3, c3, d3 and e3 are values obtained in advance by multiple regression calculation using the actual data showing the relationship between Tc, Te, Tsub, Td and RA in the supercooled state.

The equation for the vapor-liquid two-phase state is as follows.

RA = a4 + b4 x Tc + c4 x Te + d4 x Tsub + e4 x Td

Here, constants a4, b4, c4, d4 and e4 are values obtained in advance by multiple regression calculation using actual measurement data showing the relationship between Tc, Te, Tsub, Td and RA in the supercooled state.

At this time, the refrigerant quantity calculation section 413 calculates the refrigerant quantity Sd from the saturation temperature Tc and the saturation temperature Tc from the suction pressure Ps represented by the discharge pressure Pd indicated by the discharge pressure signal and the suction pressure signal and the saturated vapor curve data stored in the calculation parameter storage section 421 Calculate Te. Then, the coolant amount calculation section 413 calculates the coolant amount ratio RA using these, the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal, and the discharge temperature Td indicated by the discharge temperature signal.

The calculation formula for the supercooled state and the calculation formula for the gas-liquid two-phase state differ depending on the type of the refrigerant. Here, in order to detect the amount of refrigerant in various types of air conditioners, it is preferable that the refrigerant amount detecting device records a constant of an arithmetic expression depending on the kind of the refrigerant. The refrigerant amount calculation unit 412 reads the parameter (constant) corresponding to the refrigerant from the calculation parameter storage unit 421 and calculates the refrigerant amount according to the type of the refrigerant input from the input unit 60, for example It is acceptable.

≪ Fourth Embodiment &

Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

The air conditioner 100 of the present embodiment includes a refrigerant storage portion for storing surplus refrigerant of the refrigerant circuit 20 in addition to the configuration of the first embodiment.

Specifically, as shown in Fig. 9, the air conditioner 100 includes a receiver 218 as an example of a refrigerant storage portion for storing surplus refrigerant; And a receiver pressure reducing valve 219 as an example of a flow rate adjusting unit for reducing the pressure of the refrigerant flowing out of the receiver 218 and adjusting the flow rate of the refrigerant.

The opening degree of the receiver pressure reducing valve 219 of this embodiment is controlled by the control of the air conditioner control section 30 so that the amount and pressure of the refrigerant passing through the receiver pressure reducing valve 219 are adjusted.

The outdoor unit 10 of the air conditioner 100 is switched to the opened state or the closed state under the control of the air conditioner control unit 30 to adjust the flow rate of the refrigerant passing through the connection path 20b And a connection opening / closing valve 220 as an example of a supply amount adjusting unit.

The air conditioner 100 further includes a branch passage 20a branched from the refrigerant circuit 20 and a connection passage 20b connecting the refrigerant circuit 20 and the branch passage 20a.

The branch path 20a is branched from the piping between the condenser (outdoor heat exchanger) 102 and the first expansion valve 103 in the refrigerant circuit 20. The above-described receiver 218 is connected to the end of the branch path 20a. In addition, the above-described receiver pressure reducing valve 219 is provided in the branch passage 20a.

The connection passage 20b is branched from the piping between the receiver pressure reducing valve 219 and the receiver 218 in the branch passage 20a and is connected to the low pressure pipe 20s of the refrigerant circuit 20. The connection path 20b is provided with the above-described connection opening / closing valve 220.

The details will be described later, but in the air conditioner 100 of the present embodiment, the connection opening / closing valve 220 is normally closed. The connection opening / closing valve 220 can be switched to the open state when the discharge temperature Td of the refrigerant discharged from the compressor 201 rises to a predetermined temperature. The refrigerant stored in the receiver 218 is supplied to the compressor 201 through the connection path 20b and the rise of the discharge temperature Td of the refrigerant discharged from the compressor 201 is suppressed.

The receiver 218 of the present embodiment is formed of a material having heat conductivity such as iron. The receiver 218 has a cylindrical shape, for example, and is installed vertically in the outdoor unit 10. The receiver 218 is formed with a connecting portion to which the terminating end of the branch passage 20a is connected. In other words, in the receiver 218 of the present embodiment, the refrigerant flows in and out of the connection portion provided at the lower portion of the vertical direction.

The receiver 218 stores surplus refrigerant at the time of cooling operation and at the time of defrosting operation. Further, the receiver 218 supplies the refrigerant stored in the cooling operation mode or the defrosting operation mode to the refrigerant circuit 20 during the heating operation. In other words, in the air conditioner 100 of the present embodiment, the amount of the refrigerant circulating in the refrigerant circuit 20 is adjusted by the receiver 218. [

On the other hand, it is preferable that the volume of the receiver 218 is set so that the amount of refrigerant obtained by subtracting the optimum amount of refrigerant at the time of cooling operation from the optimum amount of refrigerant at the time of heating operation is equal to the volume converted into the supercooled liquid state. Here, the optimum amount of refrigerant means the amount of refrigerant in which the system efficiency of the heating operation and the cooling operation is the highest in the air conditioner 100. Although the details will be described later, the refrigerant circuit 20 is filled with the refrigerant having the optimum amount of refrigerant at the time of heating operation in the air conditioner 100 of the present embodiment. Therefore, when the volume of the receiver 218 is set as described above, the surplus refrigerant is received in the receiver 218 during the cooling operation, so that the cooling operation is performed with the optimum amount of refrigerant. Also, the size of the receiver 218 is suppressed.

In the air conditioner 100 of the present embodiment, R32 refrigerant or a mixed refrigerant containing at least 70% by weight of R32 is used as the refrigerant. R32 has a lower warming coefficient than, for example, R410A which is conventionally used as a refrigerant in an air conditioner. Therefore, in the present embodiment, by using the R32 refrigerant or the mixed refrigerant containing at least 70% by weight of R32, for example, as compared with the case of using the R410A refrigerant containing 50% by weight of R32 and R125, The effect is reduced.

On the other hand, the refrigerant may contain various additives such as lubricating oil for increasing the lubricity of the refrigerant in the compressor (201).

Next, the behavior of the refrigerant in the air conditioner 100 of the present embodiment will be described. First, the behavior of the refrigerant in the air conditioner 100 during the heating operation will be described.

During the heating operation, the refrigerant circuit 20 is switched to the flow path shown by the broken line in Fig. 9 by the four-way switching valve 107, and the refrigerant flows as shown by the broken arrow in Fig. That is, during the heating operation, the refrigerant is supplied to the compressor 201, the four-way switching valve 107, the indoor heat exchanger 104, the first expansion valve 103, the outdoor heat exchanger 102, The refrigerant flows in order to return to the compressor 201, thereby constituting a refrigeration cycle.

More specifically, the high-temperature, high-pressure, gaseous refrigerant compressed by the compressor 201 and discharged from the discharge portion flows into the indoor heat exchanger 104 through the four-way switching valve 107. As described above, during the heating operation, the indoor heat exchanger 104 functions as a condenser. Therefore, the refrigerant is heat-exchanged with indoor air in the indoor heat exchanger (104), condensed and liquefied, and discharged from the indoor heat exchanger (104). The high-pressure liquid refrigerant discharged from the indoor heat exchanger (104) is depressurized by the first expansion valve (103) to become a gas-liquid two-phase state, and then flows into the outdoor heat exchanger (102). During the heating operation, the outdoor heat exchanger (102) functions as an evaporator. Therefore, the refrigerant is heat-exchanged with the outside air in the outdoor heat exchanger (102), evaporated and discharged from the outdoor heat exchanger (102). The low-pressure gas-like refrigerant discharged from the outdoor heat exchanger 102 is sucked into the compressor 201 from the suction portion and compressed again.

During the heating operation, the refrigerant stored in the receiver 218 is supplied to the refrigerant circuit 20 after being reduced in pressure by the receiver pressure reducing valve 219 through the branch passage 20a.

Here, the receiver pressure reducing valve 219 is adjusted in opening degree based on the control by the air conditioner control section 30. The air conditioner 100 of the present embodiment controls the opening degree of the receiver pressure reducing valve 219 so as to prevent a large amount of refrigerant from flowing rapidly from the receiver 218 into the refrigerant circuit 20. [ On the other hand, control of the opening degree of the receiver pressure reducing valve 219 will be described later in detail

Next, the behavior of the refrigerant in the air conditioner 100 at the time of cooling operation or defrosting operation will be described.

During the cooling operation or the defrost operation, the refrigerant circuit 20 is switched to the flow path shown by the solid line in Fig. 9 by the four-way switching valve 107, and the refrigerant flows as indicated by the solid arrow in Fig. That is, during the cooling operation and the defrost operation, the refrigerant is supplied to the compressor 201, the four-way switching valve 107, the outdoor heat exchanger 102, the first expansion valve 103, the indoor heat exchanger 104, (107) in this order to return to the compressor (201).

Specifically, the high-temperature, high-pressure, gaseous refrigerant compressed in the compressor 201 and discharged from the discharge portion passes through the four-way switching valve 107 and is sucked into the outdoor heat exchanger 102. As described above, during the cooling operation or the defrost operation, the outdoor heat exchanger 102 functions as a condenser. Therefore, the refrigerant undergoes heat exchange with the outside air in the outdoor heat exchanger (102) to be condensed and liquefied, is supercooled liquid phase, and is discharged from the outdoor heat exchanger (102). The high-pressure liquid refrigerant discharged from the outdoor heat exchanger 102 branches to the refrigerant circuit 20 side and the branch line 20a side. The refrigerant in the refrigerant circuit (20) is depressurized by the first expansion valve (103) to become a vapor-liquid two-phase state and then sucked into the indoor heat exchanger (104). During the cooling operation or defrost operation, the indoor heat exchanger (104) functions as an evaporator. Therefore, the refrigerant is heat-exchanged with the indoor air in the indoor heat exchanger (104), evaporated and discharged from the indoor heat exchanger (104). The low-pressure gas-like refrigerant discharged from the indoor heat exchanger (104) is sucked into the compressor (201) from the suction portion and is compressed again.

Further, the refrigerant branched to the branch passage 20a is sucked into the receiver 218 from the connection portion after passing through the receiver pressure reducing valve 219, and is stored. On the other hand, at the time of the cooling operation and the heating operation, the receiver pressure reducing valve 219 is set to the fully opened state by the air conditioner control unit 30. [ Thus, the refrigerant branched off toward the branch passage 20a is sucked into the receiver 218 without being depressurized by the receiver pressure reducing valve 219.

Here, in the air conditioner 100, depending on the type of the outdoor heat exchanger 102, the volume of the outdoor heat exchanger 102 may be smaller than the volume of the indoor heat exchanger 104. In this case, in the cooling operation and the defrosting operation of the air conditioner 100 in which the outdoor heat exchanger 102 functions as a condenser, compared with the heating operation in which the outdoor heat exchanger 102 functions as an evaporator, The amount of refrigerant required for the compressor 20 is reduced.

That is, in the air conditioner 1 in which the optimum amount of refrigerant is filled in the refrigerant circuit 20 during the heating operation, the refrigerant circulating in the refrigerant circuit 20 , The amount of refrigerant is excessively larger than the optimum amount of refrigerant at the time of cooling operation or defrosting operation. In other words, during the cooling operation and the defrost operation, surplus refrigerant is generated in the refrigerant circuit (20).

When the cooling operation or the defrosting operation is performed with the amount of refrigerant circulating in the refrigerant circuit 20 being excessive, when the discharge pressure from the compressor 201 rises and the system efficiency of the air conditioner 100 decreases .

In contrast, in the air conditioner 100 of the present embodiment, part of the refrigerant is stored in the receiver 218 during the cooling operation and the defrosting operation, thereby suppressing the occurrence of surplus refrigerant in the refrigerant circuit (20). For this reason, in the air conditioner 100, the cooling operation and the defrosting operation are performed with the optimum amount of refrigerant. This prevents the discharge pressure from the compressor 201 from rising during the cooling operation and the defrost operation. In the cooling operation and the defrosting operation of the air conditioner 100, deterioration of the system efficiency is suppressed.

However, in the conventional air conditioner 100, there is a problem that the supercooling degree can not be sufficiently given to the refrigerant before it is sucked into the first expansion valve 103 as described below. FIG. 10 is a view showing a conventional air conditioner 100. FIG. On the other hand, in Fig. 10, the same components as those of the air conditioner 100 of the present embodiment shown in Fig. 9 are denoted by the same reference numerals, and a detailed description thereof will be omitted.

11 is a pressure-specific enthalpy diagram (p-h diagram) of the air conditioner 100 at the time of cooling operation. 11, the one-dot chain line shows the ph diagram of the air conditioner 1 of the present embodiment when the connection opening / closing valve 220 of the connection path 20b is closed, And the ph diagram of the air conditioner 1 is shown. 11, AB corresponds to the compression stroke by the compressor 201, and BC corresponds to the condensation stroke by the outdoor heat exchanger 102. In Fig. Further, the interval between the CD corresponds to the depressurization stroke by the first expansion valve 103, and the interval between DAs corresponds to the evaporation stroke by the indoor heat exchanger 104. [

10, in the conventional air conditioner 100, the receiver 218p is connected to a pipe located between the outdoor heat exchanger 102 and the first expansion valve 103 in the refrigerant circuit 20 do. In addition, unlike the air conditioner 100 of the present embodiment, the conventional air conditioner 100 shown in Fig. 10 does not have the branch passage 20a.

In the conventional air conditioner 100 shown in Fig. 10, surplus refrigerant generated during cooling operation or defrosting operation is stored in a gas-liquid two-phase state in the receiver 218p. In the air conditioner 100 shown in Fig. 10, the liquid refrigerant in the gas-liquid two phase refrigerant stored in the receiver 218p is discharged from the receiver 218p to the refrigerant circuit 20, and the refrigerant in the first expansion valve 103).

Therefore, in the air conditioner 100 shown in Fig. 10, the refrigerant discharged from the receiver 218p and sucked into the first expansion valve 103 flows into the saturated liquid state or the saturated liquid As shown in FIG. In other words, in the air conditioner 100 shown in Fig. 10, the refrigerant before being sucked into the first expansion valve 103 is difficult to be supercooled.

When the surplus refrigerant is stored in the gas-liquid two-phase state in the receiver 218p as in the air conditioner 100 shown in Fig. 10, the volume of the refrigerant to be stored tends to become large. For this reason, the receiver 218p tends to be large-sized.

On the other hand, in the air conditioner 100 of the present embodiment, the surplus refrigerant in the receiver 218 is stored in a supercooled state as described below. Thus, unlike the conventional air conditioner 100 shown in Fig. 10, the refrigerant before it is sucked into the first expansion valve 103 becomes supercooled.

That is, at the time of cooling operation or defrosting operation, the temperature of the refrigerant condensed and condensed in the outdoor heat exchanger 102 and discharged from the outdoor heat exchanger 102 is usually about 50 ° C to 60 ° C. On the other hand, the ambient temperature of the receiver 218 is usually about 20 캜 to 40 캜. Therefore, the temperature of the refrigerant discharged from the outdoor heat exchanger 102 and sucked into the receiver 218 is lower than the temperature around the receiver 218. Further, as described above, the receiver 218 of the present embodiment is made of a thermally conductive material.

Accordingly, the refrigerant discharged from the outdoor heat exchanger 102 and sucked into the receiver 218 exchanges heat with ambient air through the wall surface of the receiver 218. [ As a result, the refrigerant is supercooled in the receiver 218 and the surplus refrigerant is stored in the receiver 218 in a supercooled liquid state.

The branch passage 20a in which the receiver 218 is installed is connected to the piping between the outdoor heat exchanger 102 and the first expansion valve 103 among the refrigerant circuits 20 as described above. Therefore, the refrigerant stored in the receiver 218 is supercooled, whereby the supercooling degree SC is imparted to the refrigerant before it is sucked into the first expansion valve 103, as shown in FIG.

As a result, in the air conditioner 100 of this embodiment, the cooling effect (W1 in Fig. 11) during the cooling operation and the defrosting operation is larger than the refrigeration effect (also shown in Fig. 11) of the conventional air conditioner 100 W2 in Fig. 11). In the air conditioner 100 of the present embodiment, system efficiency is improved as compared with the air conditioner 100 shown in Fig.

Here, the R32 used as the refrigerant in the air conditioner 100 of the present embodiment has a larger enthalpy difference (calorific value difference) in the supercooled region than, for example, R410A. Therefore, in the air conditioner 100 using the R32 refrigerant or a mixed refrigerant containing at least 70% by weight of R32, the refrigerant before being sucked into the first expansion valve 103 after condensation tends to be hardly supercooled .

On the other hand, in the air conditioner 100 of the present embodiment, the refrigerant is stored in the supercooled state in the receiver 218 as described above. Accordingly, even in the case where the R32 refrigerant or a mixed refrigerant containing at least 70% by weight of R32 is used in the air conditioner 100, the refrigerant before being sucked into the first expansion valve 103 after the condensation is supercooled can do.

In the air conditioner 100 of the present embodiment, the receiver 218 is provided to make the refrigerant before it is sucked into the first expansion valve 103 into a supercooled state. For example, in order to supercool the refrigerant, the outdoor heat exchanger 102 need not be made large.

Further, in the air conditioner 100 of the present embodiment, the surplus refrigerant is stored in the supercooled liquid state during the cooling operation and the defrosting operation, so that compared with the case where the surplus refrigerant is stored in the vapor-liquid two-phase state, Can be reduced in size.

As a result, the size of the outdoor unit (10) in which the outdoor heat exchanger (102) and the receiver (218) are installed can be suppressed.

In addition, in the air conditioner 100 of the present embodiment, since the surplus refrigerant is stored in the supercooled state during the cooling operation and the defrosting operation, as compared with the case where the surplus refrigerant is stored in the vapor-liquid two-phase state, A large amount of surplus refrigerant can be stored. Therefore, for example, in the defrosting operation in which surplus refrigerant tends to easily occur, surplus refrigerant is stored in the receiver 218 and the reliability of the compressor 201 can be increased.

In the air conditioner 100 of the present embodiment, the branch passage 20a that branches from the refrigerant circuit 20 is provided, and the receiver 218 is provided at the end of the branch passage 20a. In other words, the receiver 218 is provided at a position where it does not interfere with the refrigeration cycle by the refrigerant circuit 20. Accordingly, compared with the conventional air conditioner 100 (see Fig. 10) in which the receiver 218 is installed in the refrigerant circuit 20, for example, the air conditioner 100 for storing the surplus refrigerant in the receiver 218 The variation of the ability is suppressed.

In the air conditioner (100), the refrigerant absorbs heat and evaporates in the outdoor heat exchanger (102) during heating operation. Therefore, in some cases, such as when the humidity of the outside air is high or when the outside air temperature is low, frost may adhere to the outdoor heat exchanger 102 during the heating operation. When frost is attached to the outdoor heat exchanger 102, the heat exchange in the outdoor heat exchanger 102 is inhibited and evaporation of the refrigerant in the outdoor heat exchanger 102 can be prevented. As a result, the amount of the refrigerant circulating in the refrigerant circuit (20) decreases and the heating capacity of the air conditioner (100) decreases. When the outdoor heat exchanger 102 is left with the frost attached thereto, the evaporation temperature of the refrigerant in the outdoor heat exchanger 102 is lowered, and the frost is more likely to adhere.

In order to suppress such a situation, in the air conditioner 100 of the present embodiment, when the amount of frost attached to the outdoor heat exchanger 102 exceeds a predetermined amount, defrosting operation for removing frost from the outdoor heat exchanger 102 . As described above, in the defrosting operation of the air conditioner 100, the refrigerant circulates in the refrigerant circuit 20 as in the cooling operation. As a result, the high temperature, high pressure refrigerant discharged from the compressor 201 is sucked into the outdoor heat exchanger 102, and the frost attached to the outdoor heat exchanger 102 is melted. As a result, the frost is removed from the outdoor heat exchanger (102).

Further, in the air conditioner 100 of the present embodiment, surplus refrigerant is stored in the receiver 218 during the defrosting operation, as described above. Generally, in the defrosting operation, the outdoor air temperature is low and the temperature around the receiver 218 is low as compared with the cooling operation. Therefore, compared with the case of the cooling operation, it is easy to perform heat exchange between the refrigerant stored in the receiver 218 and the ambient air of the receiver 218. As a result, a large amount of refrigerant is liable to be stored in the receiver 218 during the defrosting operation.

Subsequently, in the air conditioner 100, after the frost is removed from the outdoor heat exchanger 102 by the defrosting operation, it is possible to switch to the heating operation. In the air conditioner 100, when the mode is switched from the defrosting operation to the heating operation, the refrigerant stored in the receiver 218 is supplied to the refrigerant circuit 20 through the branch passage 20a.

More specifically, when the refrigerant circuit 20 is switched from the defrosting operation to the heating operation, the pipe between the first expansion valve 103 and the outdoor heat exchanger 102, to which the branch passage 20a is connected, The refrigerant in the gas-liquid two-phase state, which is depressurized in the compressor 103, flows in. Here, the refrigerant temperature after passing through the first expansion valve 103 at the time of the heating operation is about -15 캜 to -5 캜. The refrigerant temperature in the receiver 218 connected to the pipe between the first expansion valve 103 and the outdoor heat exchanger 102 through the branch passage 20a is also - 15 ° C to -5 ° C or so.

On the other hand, the temperature around the receiver 218 is about 0 ° C to 10 ° C. That is, when the mode is switched from the defrosting operation to the heating operation, the refrigerant temperature in the receiver 218 becomes lower than the temperature around the receiver 218. Accordingly, a part of the refrigerant stored in the receiver 218 is heat-exchanged with the ambient air through the wall surface of the receiver 218 to evaporate.

When a part of the refrigerant evaporates in the receiver 218, the refrigerant in the receiver 218 is separated into the gas-like portion and the liquid-like portion. The gas-form coolant is located on the vertical upper side of the receiver 218, and the liquid coolant is located on the vertically lower side. When the evaporation of the refrigerant further proceeds in the receiver 218 to increase the amount of gaseous refrigerant, the liquid refrigerant is pressed by the gaseous refrigerant. As a result, liquid refrigerant is discharged to the branch passage 20a from the connection portion provided on the vertical lower portion of the receiver 218. [

The refrigerant discharged from the receiver 218 to the branch passage 20a is supplied to the refrigerant circuit 20 after passing through the receiver pressure reducing valve 219. [ As a result, the amount of the refrigerant circulating in the refrigerant circuit 20 increases, and the heating operation is performed with the optimum amount of refrigerant.

Further, when the mode is switched from the defrosting operation to the heating operation, the temperature around the receiver 218 is higher than the saturation temperature equivalent to the pressure in the receiver 218 as described above. Therefore, during the heating operation, the refrigerant in the receiver 218 is maintained in the overheated gas state. Thus, the intrusion of the liquid refrigerant into the receiver 218 is suppressed. That is, during the heating operation, the refrigerant is prevented from entering the receiver 218 from the refrigerant circuit 20 through the branch passage 20a.

In the receiver 218 of the present embodiment, the connecting portion through which the refrigerant enters and exits is provided below the vertical portion of the receiver 218. Thus, for example, when the air conditioner 1 is switched from the defrosting operation to the heating operation and the refrigerant stored in the receiver 218 is discharged from the receiver 218, the lubricant or the like contained in the refrigerant flows into the receiver 218, Is suppressed.

Concretely, R32 used in the air conditioner 100 of the present embodiment is low in solubility of lubricating oil or the like at low temperature as compared with, for example, R410A. Therefore, as compared with R410A, the refrigerant and the lubricating oil are easily separated from the R32 refrigerant or a mixed refrigerant containing 70% by weight or more of R32. However, in the present embodiment, the connection portion is provided in the vertical lower portion of the receiver 218, so that the lubricating oil separated from the refrigerant in the receiver 218 is discharged from the receiver 218 by gravity. Accordingly, the lubricant is prevented from remaining in the receiver 218, and the lowering of the lubricant of the refrigerant in the compressor 201 is suppressed.

Next, the opening and closing control of the receiver pressure reducing valve 219 when switching from the defrosting operation to the heating operation in the air conditioner 100 will be described. In the air conditioner 100 of the present embodiment, the air conditioner control section 30 switches the opening degree of the receiver pressure reducing valve 219 to be smaller than that in the defrosting operation mode when switching from the defrosting operation to the heating operation .

First, during the cooling operation and defrosting operation, the receiver pressure reducing valve 219 is set to the open state by the air conditioner control unit 30 in order to store the surplus refrigerant in the receiver 218. [ Accordingly, during the cooling operation and the defrosting operation, the surplus refrigerant entering the branch passage 20a passes through the receiver pressure reducing valve 219 without being decompressed. The refrigerant having passed through the receiver pressure reducing valve 219 is stored in the receiver 218 in a supercooled state as described above.

On the other hand, when switching from the defrosting operation to the heating operation, the opening degree of the receiver pressure reducing valve 219 is switched to be small by the air conditioner control section 30 in accordance with the timing of switching to the heating operation. As a result, the flow rate of the refrigerant passing through the receiver pressure reducing valve 219 per unit time becomes smaller as compared with the case where the receiver pressure reducing valve 219 is fully opened.

By controlling the opening degree of the receiver pressure reducing valve 219 as described above, it is possible to suppress the sudden flow of the refrigerant discharged from the receiver 218 into the refrigerant circuit 20 when switching from the defrosting operation to the heating operation.

That is, when switching from the defrosting operation to the heating operation, evaporation of the refrigerant occurs in the receiver 218 as described above, and a large amount of refrigerant is discharged from the receiver 218. Therefore, when the receiver pressure reducing valve 219 is fully opened, a large amount of refrigerant discharged from the receiver 218 rapidly flows into the refrigerant circuit 20 through the branch passage 20a. When the refrigerant discharged from the receiver 218 suddenly flows into the refrigerant circuit 20, the amount of refrigerant sucked into the compressor 201 becomes excessive. In this case, there is a fear that the compressor 201 may fail.

On the other hand, in the present embodiment, the opening degree of the receiver pressure reducing valve 219 is reduced and the amount of the refrigerant passing through the receiver pressure reducing valve 219 is adjusted so that the refrigerant flowing from the branch passage 20a to the refrigerant circuit 20 The amount of refrigerant decreases. Accordingly, the excessive amount of the refrigerant sucked into the compressor 201 is suppressed, and the failure of the compressor 201 is suppressed.

Next, the operation of the connection path 20b and the connection opening / closing valve 220 will be described. 12 is a diagram showing the relationship between the opening and closing of the connection opening / closing valve 220 and the refrigerant temperature discharged from the compressor 201 in the present embodiment. Fig. 13 is a flowchart showing the sequence of opening / closing control of the connection opening / closing valve 220 executed by the air conditioner control section 30 of the present embodiment. In the air conditioner 100 of the present embodiment, opening and closing of the connection opening / closing valve 220 is controlled on the basis of the temperature detection result by the discharge temperature sensor 206. Thus, the rise of the refrigerant temperature (discharge temperature) discharged from the compressor 201 is suppressed. Hereinafter, the opening / closing control of the connection opening / closing valve 220 will be described in detail.

In the air conditioner 100 of the present embodiment, the connection opening / closing valve 220 is normally closed.

First, the air conditioner control unit 30 acquires the refrigerant temperature (discharge temperature Td) discharged from the compressor 201 detected by the discharge temperature sensor 206 (step 301). Next, the air conditioner control unit 30 compares the discharge temperature Td obtained in step 301 with the first reference temperature T1, which is an example of a predetermined reference temperature (step 302). If it is determined that the discharge temperature T is lower than the first reference temperature T1 (NO in step 302), the air conditioner control section 30 returns to step 301 to continue the processing.

On the other hand, if it is determined that the discharge temperature T is equal to or higher than the first reference temperature T1 (YES in step 302), the air conditioner control section 30 switches the connection opening / closing valve 220 from the closed state to the open state 303). Thus, the supercooled refrigerant stored in the receiver 218 is supplied to the low-pressure pipe 20s of the refrigerant circuit 20 through the connection passage 20b.

Here, the connection passage 20b is connected to the pipe between the receiver 218 and the receiver pressure reducing valve 219 in the branch passage 20a. Therefore, when the connection opening / closing valve 220 is opened, the refrigerant stored in the receiver 218 is supplied to the low-pressure pipe 20s while being not under reduced pressure by the receiver pressure-reducing valve 219 and being in a supercooled state.

As a result, the temperature of the refrigerant sucked into the compressor 201 from the low-pressure pipe 20s decreases, and the compressor 201 is cooled. Then, the discharge temperature T of the refrigerant discharged from the compressor 201 decreases.

Subsequently, the air conditioner control unit 30 acquires again the discharge temperature Td detected by the discharge temperature sensor 206 (step 304).

Then, the air conditioner control unit 30 compares the discharge temperature Td obtained in Step 304 with the second reference temperature T2 which is an example of another predetermined reference temperature (Step 305). If it is determined that the discharge temperature Td is higher than the second reference temperature T2 (NO in step 305), the air conditioner control section 30 returns to step 304 to continue the processing.

On the other hand, if it is determined that the discharge temperature Td is equal to or lower than the second reference temperature T2 (YES in step 305), the air conditioner control section 30 switches the connection opening / closing valve 220 from the open state to the closed state (step 306) .

Thus, the supply of the refrigerant to the low-pressure pipe 20s through the connection passage 20b is stopped. As a result, the discharge temperature T of the refrigerant discharged from the compressor 201 is lowered.

As described above, in the air conditioner 100 of this embodiment, by repeatedly performing the opening / closing control of the connection opening / closing valve 220, the refrigerant temperature discharged from the compressor 201 is maintained within the predetermined range Between T1 and the second reference temperature T2).

As a result, stable air-conditioning operation can be performed in the air conditioner 100, and deterioration of system efficiency is suppressed. Further, the occurrence of the problem of the compressor 201 accompanying the rise of the discharge temperature is suppressed.

In the air conditioner 100 of the present embodiment, R32 refrigerant or a mixed refrigerant containing R32 at 70 wt% or more is used as the refrigerant. Compared to R410A, R32 has such a property that the discharge temperature of the refrigerant discharged from the compressor 201 tends to be higher.

Further, for example, when the compression ratio of the refrigerant in the compressor 201 at the time of the heating operation in the state where the outdoor air temperature is low is large, the refrigerant discharge temperature Td is likely to rise.

On the other hand, in the present embodiment, the compressor 201 can be directly cooled by the supercooled refrigerant stored in the receiver 218. Therefore, even when the refrigerant whose discharge temperature Td is likely to rise is used, or when the air conditioning operation is performed under the condition that the discharge temperature Td is likely to rise, the rise of the discharge temperature Td is suppressed.

Here, the first reference temperature T 1 is set to a temperature lower than the discharge temperature limit Ta of the compressor 201. On the other hand, the discharge temperature limit Ta is a temperature at which the problem of the compressor 201 such as deterioration of the sealant and the lubricating oil of the compressor 201 can occur. By setting the first reference temperature T1 to a temperature lower than the discharge temperature limit Ta, the discharge temperature T is prevented from reaching the discharge temperature limit Ta and the deterioration of the compressor 201 is suppressed. In this example, the discharge temperature limit Ta of the compressor 201 is 120 占 폚, and the first reference temperature T1 is set at 110 占 폚.

The second reference temperature T2 is not particularly limited, but is set to a temperature lower than the first reference temperature T1. In this example, the second reference temperature T2 is set at 90 占 폚.

On the other hand, in the present embodiment, the connection switching valve 220 is switched to either the open state or the closed state in accordance with the discharge temperature Td. However, the opening degree of the connection switching valve 220 may be varied It is acceptable to use a configuration. More specifically, the air conditioner control unit 30 controls the opening degree of the connection opening / closing valve 220 to be larger as the discharge temperature Td becomes higher and decrease the opening degree of the connection opening / closing valve 220 as the discharge temperature Td becomes lower You can do it.

In addition, in the air conditioner 100 of the present embodiment, the amount of refrigerant circulating through the refrigerant circuit 20 can be adjusted by opening the connection opening / closing valve 220. That is, when the connection opening / closing valve 220 is opened, the refrigerant stored in the receiver 218 is supplied to the low pressure pipe 20s of the refrigerant circuit 20. As a result, the amount of refrigerant stored in the receiver 218 decreases, and the amount of refrigerant circulating in the refrigerant circuit 20 increases.

Therefore, depending on conditions such as outside air temperature and room temperature, for example, by opening the connection opening / closing valve 220 at the time of cooling operation under a low ambient temperature and increasing the amount of refrigerant circulating through the refrigerant circuit 20 , The air conditioning operation can be performed with the optimum amount of refrigerant.

The first expansion valve 103, the receiver decompression valve 219, and the connection open / close valve 219 are opened and closed by the air conditioner control unit 30, It may be controlled by interlocking the opening and closing of the door 220. Thus, for example, when the cooling operation is performed after the cooling operation is stopped, the temperature of the refrigerant sucked into the compressor 201 can be lowered.

Specifically, when the cooling operation is stopped, the air conditioner control unit 30 keeps the receiver pressure reducing valve 219 in the open state, keeps the connection open / close valve 220 in the closed state, 1 switch the expansion valve 103 to the closed state. Accordingly, when the cooling operation is stopped, the amount of refrigerant flowing from the refrigerant circuit (20) to the branch passage (20a) increases and the refrigerant is stored in the receiver (218). Thereafter, when the cooling operation is resumed, the air conditioner control unit 30 switches the first expansion valve 103 and the connection opening / closing valve 220 to the open state. As a result, the supercooled refrigerant stored in the receiver 218 is supplied to the low-pressure pipe 20s, and the temperature of the refrigerant sucked into the compressor 201 lowers. As a result, even when the cooling operation in which the temperature of the compressor 201 is likely to be high is started, the system efficiency of cooling operation is prevented from being lowered.

On the other hand, in the above-described example, the air conditioner 1 having the receiver pressure reducing valve 219 as an example of the flow rate adjusting means has been described. However, the flow rate regulating means is not limited to the pressure reducing valve. For example, an opening / closing valve, a flow rate control valve, or the like may be used as the flow rate regulating means. In this case, the flow rate of the refrigerant discharged from the receiver 218 to the refrigerant circuit 20 through the branch passage 20a and the speed of the refrigerant can be adjusted.

On the other hand, in the above description, the R32 refrigerant used as the refrigerant used in the air conditioner 100 or the mixed refrigerant containing R32 in an amount of 70% by weight or more is taken as an example, but the present embodiment is also applied to the air conditioner 100 using other refrigerant can do. However, in consideration of the characteristics of R32 as described above, the present embodiment is preferably applied to the air conditioner 100 using R32 refrigerant or a mixed refrigerant containing R32 at 70 wt% or more.

≪ Embodiment 5 >

Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

14, the air conditioner 100 according to the present embodiment is provided with the supercooling (supercooling) system for supercooling the refrigerant after being condensed in the outdoor heat exchanger 102 or the indoor heat exchanger 104, (Sub cooler) In this example, the supercooler 80 is installed in the outdoor unit 10 of the air conditioner 1.

As shown in Fig. 15, the supercooler 80 has a first pipe 81 and a second pipe 82 arranged in parallel with each other. The first pipe 81 has a first inlet 81a through which the refrigerant flows and a first outlet 81b through which the refrigerant is discharged. Similarly, the second pipe 82 has a second inlet 82a through which the refrigerant flows and a second outlet 82b through which the refrigerant is discharged.

The first inlet 81a of the first pipe 81 and the second inlet 82a of the second pipe 82 are located at positions opposite to each other in the refrigerant transport direction in the subcooler 80 Respectively. Likewise, the first outlet 81b of the first pipe 81 and the second outlet 82b of the second pipe 82 are installed at positions opposite to each other in the refrigerant transport direction in the subcooler 80 do.

Accordingly, in the subcooler 80, the flow direction of the coolant flowing through the first pipe 81 and the flow direction of the coolant flowing through the second pipe 82 are opposite to each other. In other words, in the supercooler 80, the refrigerant flowing through the first pipe 81 and the refrigerant flowing through the second pipe 82 are countercurrent.

14, the air conditioner 1 has first expansion valves 204a and 204b for inflating the supercooled refrigerant in the supercooler 80 to low temperature and low pressure. In this example, one of the first expansion valves 204a is installed in the indoor unit 10 and the other of the first expansion valves 204b is installed in the outdoor unit 10. [ In this embodiment, when the air conditioner 100 performs the cooling operation or the defrosting operation, the refrigerant is inflated in one of the first expansion valves 204a. Further, when performing the heating operation, the refrigerant is inflated in the other first expansion valve 204b.

The air conditioner 100 also has a connection opening / closing valve 221 for adjusting the amount of refrigerant passing through the connection path 25 to be described later.

The air conditioner 100 also includes a supercooling-degree reducing valve (second expansion valve) 215 for reducing the refrigerant flowing in the supercooling branch path 22 described later and adjusting the flow rate of the refrigerant.

The compressor 201 of the present embodiment has an intermediate-pressure suction portion 201c through which an intermediate-pressure refrigerant is sucked through an injection path 24 to be described later.

The air conditioner 1 of the present embodiment has a supercooling furnace 21 in which the supercooler 80 is installed. The supercooling furnace 21 is connected to piping between one of the first expansion valves 204a and the other of the first expansion valves 204b in the refrigerant circuit 20 through a bridge circuit 23 described later.

The supercooling furnace 21 is connected to the second connecting point 23b of the bridge circuit 23 and the first inlet 81a of the first pipe 81 in the supercooler 80 by an upstream supercooling (21a). The supercooling furnace 21 is connected to the first outlet 81b of the first pipe 81 in the subcooler 80 and the downstream end of the downstream side connecting the fourth connection point 23d of the bridge circuit 23 And a supercooling path 21b.

The air conditioner 100 according to the present embodiment is branched from the upstream side supercooling path 21a and connected to the second inlet portion 82a of the second pipe 82 in the supercooler 80, (22).

The air conditioner 100 also includes a bridge circuit (not shown) for making the flow direction of the refrigerant in the supercooling path 21 and the supercooling branch path 22 in one direction during the cooling operation (during the defrost operation) and the heating operation 23).

The bridge circuit 23 is constituted by connecting four pipes. More specifically, the bridge circuit 23 includes a first check valve 231, a second check valve 232, a third check valve 233, and a fourth check valve 234, Have pipelines. These are connected in a closed loop manner through the first connection point 23a, the second connection point 23b, the third connection point 23c and the fourth connection point 23d.

In the bridge circuit 23, a pipe extending from the other first expansion valve 204b of the refrigerant circuit 20 is connected to the first connection point 23a. A pipe extending from one of the first expansion valves 204a of the refrigerant circuit 20 is connected to the third connection point 23c. An upstream supercooling path 21a is connected to the second connection point 23b. The downstream side supercooling path 21b is connected to the fourth connecting point 23d.

The air conditioner 1 also has an injection path 24 for sucking the refrigerant that has passed through the second pipe 82 of the supercooler 80 into the intermediate pressure suction portion 201c of the compressor 201 do. The injection path 24 is connected to the second outlet portion 82b of the second pipe 82 in the subcooler 80 as shown in Fig.

The air conditioner 1 also has a connection path 25 for connecting the injection path 24 and the low pressure pipe 20s in the refrigerant circuit 20. [

The air conditioner 100 of the present embodiment is provided with an inlet temperature sensor 222 provided in the supercooling branch path 22 for detecting the temperature of the refrigerant before being sucked into the second pipe 82 of the subcooler 80, Respectively. The air conditioner 100 also has an outlet temperature sensor 223 installed in the injection path 24 for detecting the temperature of the refrigerant discharged from the second outlet 82b of the second pipe 82. The air conditioner 100 further includes a supercooling temperature sensor 224 installed at the downstream side supercooling passage 21b for detecting the temperature of the refrigerant discharged from the first outlet 81b of the first pipe 81 do.

The opening degree of the supercooling pressure reducing valve 215 is controlled by the air conditioner control section 30 based on the detection results of the inlet temperature sensor 222, the outlet temperature sensor 223 and the supercooling temperature sensor 224. In this embodiment, Is controlled. On the other hand, the opening control of the supercooling reducing valve 215 by the air conditioner control unit 30 will be described later.

In the air conditioner 100 of the present embodiment, R32 (HFC32) as a refrigerant and a non-azeotropic mixed refrigerant of two or three kinds including HFO1234yf or HFO1234ze are used. In addition, the nonspecifically mixed refrigerant may contain natural refrigerant.

Here, the non-azeotropic mixed refrigerants including R32 and HFO1234yf or HFO1234ze have a lower warming coefficient than, for example, R32 refrigerant and the like. Therefore, in the air conditioner 100 of the present embodiment, the influence on the environment is reduced by using the non-azeotropic mixed refrigerant including R32 as the refrigerant and HFO1234yf or HFO1234ze.

In the air conditioner 100 of the present embodiment, it is preferable that the content of R32 is less than 70% by weight, the content of HFO1234yf or HFO1234ze is less than 30% by weight, and the rest is natural refrigerant . By setting the mixing ratio of the non-azeotropic mixed refrigerant as described above, the temperature gradient in the saturation range of the non-azeotropic mixed refrigerant becomes 2 degrees or more. In this case, as will be described later, the heat exchange efficiency in the supercooler 30 is improved, and the refrigerating effect of the air conditioner 100 is improved.

Next, the behavior of the refrigerant in the air conditioner 100 of the present embodiment will be described with reference to Figs. 14 and 15. Fig. On the other hand, in the air conditioner 100 of the present embodiment, the behavior of the refrigerant in the refrigerant circuit 20 is the same as in the fourth embodiment. Therefore, the behavior of the refrigerant in the bridge circuit 23, the supercooling path 21, and the supercooling branch path 22 will be described here.

As described above, the bridge circuit 23 includes the first check valve 231 to the fourth check valve 234. 15, the refrigerant flows in one direction from the first check valve 231 to the fourth check valve 234. As shown in Fig.

The refrigerant condensed in the outdoor heat exchanger 102 and having passed through the first expansion valve 204b at the other end of the first expansion valve 204b flows into the first connection point 23a when the air conditioner 100 performs the cooling operation or defrost operation, To the bridge circuit 23. The refrigerant flowing into the bridge circuit 23 passes through the first check valve 231 and is discharged from the second connecting point 23b to the upstream side supercooling path 21a.

Subsequently, the refrigerant discharged to the upstream side supercooling furnace 21a flows into the subcooling path 21 side of the supercooler 80 toward the first pipe 31 and the supercooling branch path 22 toward the second pipe 82 ) Side.

The refrigerant on the side of the supercooling furnace 21 flows into the first pipe 81 from the first inlet portion 81a. The refrigerant flowing into the first pipe 81 is heat-exchanged with the refrigerant flowing through the second pipe 82 and then discharged from the first outlet portion 81b to the downstream side supercooling passage 21b. The refrigerant discharged to the downstream side supercooling passage 21b flows into the bridge circuit 23 through the fourth connecting point 23d. The refrigerant flowing into the bridge circuit 23 passes through the third check valve 233 and is discharged to the refrigerant circuit 20 from the third connecting point 23c. The refrigerant discharged to the refrigerant circuit (20) is decompressed by one of the first expansion valves (204a), and then circulates through the refrigerant circuit (20) as in the fourth embodiment.

Further, the refrigerant on the side of the supercooling branch path 22 flows into the second pipe 82 from the second inlet portion 82a.

The refrigerant flowing into the second pipe 82 is heat-exchanged with the refrigerant flowing through the first pipe 81 and then discharged from the second outlet 82b to the injection path 24. [

Then, the refrigerant discharged into the injection path (24) is sucked into the compressor (201) from the intermediate pressure suction portion (201c).

On the other hand, the heat exchange of the refrigerant in the supercooler 80 will be described later in detail.

On the other hand, when the air conditioner 100 performs the heating operation, the refrigerant condensed in the indoor heat exchanger 104 and having passed through the first expansion valve 204a flows from the third connection point 23c to the bridge circuit 23). The refrigerant flowing into the bridge circuit 23 passes through the second check valve 232 and then is discharged from the second connecting point 23b to the upstream side supercooling path 21a.

Subsequently, the refrigerant discharged to the upstream side supercooling furnace 21a flows into the subcooling path 21 toward the first pipe 81 of the subcooler 80 and the subcooling path 22 toward the second pipe 82 ) Side.

The refrigerant on the side of the supercooling furnace 21 flows into the first pipe 81 from the first inlet portion 81a as in the cooling operation. The refrigerant flowing into the first pipe 81 is heat-exchanged with the refrigerant flowing through the second pipe 82 and then discharged from the first outlet portion 81b to the downstream side supercooling passage 21b. The refrigerant discharged to the downstream side supercooling passage 21b flows into the bridge circuit 23 through the fourth connecting point 23d. The refrigerant flowing into the bridge circuit 23 passes through the fourth check valve 234 and is then discharged to the refrigerant circuit 20 from the first connecting point 23a. The refrigerant discharged to the refrigerant circuit 20 is decompressed by one of the first expansion valves 204b and then circulated in the refrigerant circuit 20 as in the fourth embodiment.

Further, the refrigerant on the side of the supercooling branch path 22 flows into the second pipe 82 from the second inlet portion 82a as in the cooling operation. The refrigerant flowing into the second pipe 82 is heat-exchanged with the refrigerant flowing through the first pipe 81 and then discharged from the second outlet 82b to the injection path 24. [

Then, the refrigerant discharged into the injection path (24) is sucked into the compressor (201) from the intermediate pressure suction portion (201c).

As described above, in the present embodiment, the flow direction of the refrigerant in the supercooling passage 21 and the supercooling branch passage 22 is the same in the cooling operation (during the defrost operation) and the heating operation. As a result, the refrigerant flowing through the first pipe 81 and the second pipe 82 of the supercooler 80 is countercurrent in both the cooling operation and the heating operation.

Subsequently, the heat exchange of the refrigerant in the supercooler 80 of the present embodiment will be described.

16 is a pressure-specific enthalpy diagram (p-h diagram) of the air conditioner 100 to which the present embodiment is applied. Here, the p-h line diagram of the air conditioner 100 at the time of the cooling operation is shown, but the tendency of the heating operation trial is the same.

In Fig. 16, the AB interval corresponds to the compression stroke by the compressor 201, and the BC interval corresponds to the condensation stroke by the outdoor heat exchanger 102. Fig. Corresponding to the depressurizing stroke by the supercooling pressure reducing valve 215 between CEs. The point G corresponds to the intermediate-pressure suction portion 201c in the compressor 201. [

Also, between the CC 'and the EF corresponds to the heat exchange stroke by the subcooler 80. Concretely, the interval CC 'corresponds to the refrigerant state from the first inlet 81a to the first outlet 81b in the first pipe 81 of the subcooler 80. The interval between the EFs corresponds to the refrigerant state from the second inlet 82a to the second outlet 82b in the second pipe 82 of the subcooler 80. [

The interval between C'D corresponds to the depressurization stroke by the first expansion valve 204a, and the interval between DAs corresponds to the evaporation stroke by the indoor heat exchanger 104. [

On the other hand, in Fig. 16, the one-dot chain lines Y1 and Y2 represent the isotherms. Here, Y1 corresponds to the refrigerant temperature at the point C (the first inlet portion 81a). Further, Y2 corresponds to the refrigerant temperature at the point C '(first outlet portion 81b).

In the subcooler 80, heat exchange is performed between the refrigerant flowing through the first pipe 81 and the refrigerant flowing through the second pipe 82, as described above. Thus, the refrigerant flowing through the first pipe 81 is supercooled.

Specifically, the refrigerant that has been condensed by the outdoor heat exchanger 102 or the indoor heat exchanger 104 flows into the first pipe 81. That is, in the first pipe 81, as shown between CC 'in FIG. 16, the refrigerant in the high-pressure liquid state after the condensation flows.

On the other hand, the refrigerant after being reduced in pressure by the supercooling reducing valve 215 provided in the supercooling branch path 22 flows into the second pipe 82. That is, as shown between EF in FIG. 16, refrigerant in the gas-liquid two-phase state (saturated region) flows from the low-temperature and low-pressure state to the second pipe 32 as compared with the refrigerant flowing through the first pipe 81.

In the supercooler 80, heat is taken from the high-pressure liquid refrigerant flowing through the first pipe 81 by the cold-low-pressure refrigerant flowing through the second pipe 82. Accordingly, in the supercooler (80), the refrigerant flowing through the first pipe (81) is supercooled.

17A and 17B are views showing the relationship between the coolant temperature flowing through the first pipe 81 and the coolant temperature flowing through the second pipe 82 in the supercooler 80. FIG. 17A shows the relationship of the present embodiment in which the refrigerant flowing through the first pipe 81 and the refrigerant flowing through the second pipe 82 are countercurrent. On the other hand, FIG. 17 (b) shows the relationship when the refrigerant flowing through the first pipe 81 and the refrigerant flowing through the second pipe 82 are in a parallel flow.

As described above, in the present embodiment, R32 is used as the refrigerant, and non-azeotropic mixed refrigerant containing HFO1234yf or HFO1234ze is used. By using the non-azeotropic mixed refrigerant, a temperature gradient is generated in the refrigerant in the second pipe 82 through which the refrigerant in the vapor-liquid two-phase state (saturation region) flows. In other words, as shown in Fig. 17A, a temperature difference? S1 is generated in the refrigerant at the second inlet portion 82a (point E) and the second outlet portion 82b (point F).

As described above, in the present embodiment, the refrigerant flowing through the first pipe 81 and the second pipe 82 in the supercooler 80 is a countercurrent flow. 17 (a) or 16, the refrigerant flowing through the first pipe 81 flows from the first inlet 81a (point C) to the first outlet 81b (point C '), The temperature difference between the refrigerant flowing through the first pipe 82 and the refrigerant flowing through the second pipe 82 is secured. In other words, as compared with the case of FIG. 17 (b) in which the refrigerant flowing through the first pipe 81 and the second pipe 82 are parallel flows, the average of the refrigerants of the first pipe 81 and the second pipe 82 The temperature difference becomes large.

As a result, compared with the case where the refrigerant flowing through the first pipe 81 and the second pipe 82 is a parallel flow, for example, the first expansion valve 204a (the first expansion valve 204a A large supercooling degree SC is given by the refrigerant before it is sucked into the refrigerant circuit (the valve 204b).

In the air conditioner 100 of the present embodiment, the cooling effect is improved in both the cooling operation and the heating operation, as compared with the case where this configuration is not employed.

As described above, in the present embodiment, R32 is used as the refrigerant, and non-azeotropic mixed refrigerant containing HFO1234yf or HFO1234ze is used.

Non-azeotropic refrigerants, including R32 and HFO1234yf or HFO1234ze, have low refrigeration effects compared to, for example, R32 refrigerants. Therefore, in order to obtain an efficiency equivalent to that of the R32 refrigerant, it is necessary to increase the amount of refrigerant circulated in the air conditioner 100. [ However, when the amount of refrigerant circulated in the air conditioner 100 is increased, the pressure loss occurring in the subcooler 80 is liable to increase. In this case, the heat exchange efficiency in the supercooler 80 is lowered, and it becomes difficult to sufficiently supercool the refrigerant in the supercooler 80. [

On the other hand, in the supercooler 80 of the present embodiment, heat exchange is performed in a countercurrent flow in both the cooling operation and the heating operation. Thus, as compared with the case where the supercooler 80 performs heat exchange with the parallel flow, the lowering of the heat exchange efficiency in the supercooler 80 is suppressed. As a result, it becomes possible to sufficiently supercool the refrigerant in the supercooler (80). Further, even in the case of using a non-azeotropic mixed refrigerant containing R32, HFO1234yf or HFO1234ze, which has lower refrigeration effect than R32 refrigerant, deterioration of the refrigerating effect in the air conditioner 100 is suppressed.

Further, in this embodiment, a supercooling branch path 22 for branching at the supercooling path 21 is provided on the upstream side of the supercooler 80. In the supercooler 80, the refrigerant flowing through the first pipe 81 is supercooled by the refrigerant introduced into the second pipe 82 by being divided (branched) into the supercooling branch path 22.

The amount of the refrigerant flowing into the first pipe 81 of the supercooler 80 from the supercooling furnace 21 is reduced in comparison with the case where the supercooling branch path 22 is not provided in the supercooler 80 of the present embodiment, . As a result, the pressure loss generated in the first pipe 81 of the supercooler 80 is reduced, and the lowering of the heat exchange efficiency in the supercooler 80 is further suppressed.

In the air conditioner 100 of the present embodiment, the refrigerant discharged from the second outlet portion 82b of the second pipe 82 in the supercooler 80 is discharged to the intermediate pressure suction portion 201c. In other words, the intermediate-pressure suction portion 201c of the compressor 201 sucks the intermediate-pressure refrigerant whose temperature has decreased due to heat exchange in the subcooler 80. [

As a result, in the air conditioner 1 of the present embodiment, the refrigerant temperature at the intermediate pressure suction portion 201c (point G) of the compressor 201 drops as shown in Fig. This makes it possible to reduce the refrigerant temperature (discharge temperature) discharged from the discharge portion (point B) of the compressor 201, as compared with the case where the refrigerant discharged from the second piping 32 is not sucked into the intermediate pressure suction portion 201c, Is suppressed. Further, for example, occurrence of problems such as deterioration of the service life of the compressor 201 accompanying the increase of the discharge temperature is suppressed.

The air conditioner 100 of the present embodiment has a connection path 25 for connecting the injection path 24 and the low pressure pipe 20s in the refrigerant circuit 20. The connection path 25 is provided with a connection opening / closing valve 221 whose opening degree is controlled by the air conditioner control section 30.

The pressure of the refrigerant flowing through the injection path 24 and the second pipe 82 of the supercooler 80 can be adjusted by controlling the opening degree of the connection opening / closing valve 221 in this embodiment.

More specifically, when the connection opening / closing valve 221 is opened, the low-pressure pipe 20s of the refrigerant circuit 20 is connected to the injection path 24 through the connection passage 25. [ This reduces the pressure of the refrigerant flowing through the injection path 24 and the second pipe 82 of the subcooler 80, as compared with the case where the connection opening / closing valve 221 is closed.

Here, when the pressure of the refrigerant flowing through the second pipe 82 decreases, the state of the refrigerant flowing through the second pipe 82 changes from EF to E'F 'in Fig. As a result, the average temperature difference between the refrigerant flowing through the second pipe 82 and the refrigerant flowing through the first pipe 81 becomes larger. As a result, the heat exchange efficiency in the supercooler 80 is improved, and the refrigerant flowing through the first pipe 81 is further supercooled. Then, the refrigerating effect in the air conditioner 100 is further improved.

Next, the opening control of the supercooling reducing valve 215 performed by the air conditioner control unit 30 will be described.

18 is a flowchart showing the procedure of the opening control of the supercooling reducing valve 215 executed by the air conditioner control section 30 of the present embodiment. In the air conditioner 100 of the present embodiment, on the basis of the detection results by the inlet temperature sensor 222, the outlet temperature sensor 223 and the supercooling temperature sensor 224, the reliability assurance operation, the efficiency priority operation, Is performed. In each operation, the opening degree of the supercooling reducing valve 215 is adjusted by different control.

Here, the reliability assurance operation is an operation for securing the reliability of the compressor 201 and preventing the failure of the compressor 201. [ In addition, the efficiency first operation means operation in which the system efficiency of the air conditioner 100 is prioritized. In addition, the capability priority operation is an operation in which the air conditioning capability (heating capability, cooling capability) of the air conditioner 100 is prioritized.

When the air conditioning operation is performed in the air conditioner 100, the air conditioner control unit 30 acquires the refrigerant temperature detected by the inlet temperature sensor 222 and the outlet temperature sensor 223 (step 401 ). In the following description, the temperature detected by the inlet temperature sensor 222 is referred to as an inlet temperature Sa, and the temperature detected by the outlet temperature sensor 223 is referred to as an outlet temperature Sb. The temperature detected by the supercooling temperature sensor 224 is called a supercooling temperature Sc.

Subsequently, the air conditioner control unit 30 determines whether the inlet temperature Sa and the outlet temperature Sb acquired in step 401 satisfy predetermined requirements. More specifically, the air conditioner control unit 30 compares the temperature difference? S1 (= Sb-Sa) obtained by subtracting the inlet temperature Sa from the outlet temperature Sb with the third predetermined reference temperature T3 (step 402). Here, the temperature difference? S1 corresponds to the temperature difference (superheat degree) between the second outlet 82b and the second inlet 82a of the refrigerant flowing through the second pipe 82 of the subcooler 80 (see FIG. 17) . The third reference temperature T3 is an optimum value of the degree of superheat of the supercooler 80, and is set in the range of -1 占 폚 to 3 占 폚, for example.

If the temperature difference? S1 is less than the third reference temperature T3 (? S1 <T3; NO in step 402), the reliability ensuring operation is performed based on the control by the air conditioner control section 30 (step 403).

The reliability assurance operation is an operation for securing the reliability of the compressor 201 as described above. In the reliability ensuring operation, on the basis of control by the air conditioner control unit 30, the supercooling reducing valve 215 is switched to the closed state. In this embodiment, when the temperature difference? S1 is less than the third reference temperature T3, the reliability assurance operation is performed, thereby suppressing the suction of the liquid refrigerant into the intermediate pressure suction portion 201c of the compressor 201. [

That is, when the temperature difference? S1 is less than the third reference temperature T3, the evaporation of the refrigerant flowing through the second pipe 82 of the supercooler 80 tends to become insufficient. In this case, the liquid refrigerant is discharged from the second outlet 82b of the second pipe 82 to the injection path 24. There is a possibility that the liquid refrigerant is sucked into the intermediate pressure suction portion 201c of the compressor 201 through the injection path 24. When the liquid refrigerant is sucked into the intermediate pressure suction portion 201c of the compressor 201, there is a possibility that the compressor 201 may be broken due to the liquid compression occurring in the compressor 201. [

On the other hand, in this embodiment, as the reliability assurance operation, the supercooling reducing valve 215 is switched to the closed state so that the discharge of the liquid refrigerant from the second outlet portion 82b of the second pipe 82 is suppressed. As a result, the suction of the liquid refrigerant into the intermediate-pressure suction portion 201c of the compressor 201 is suppressed. As a result, the failure of the compressor (201) is suppressed and the reliability is ensured.

On the other hand, when the temperature difference? S1 is equal to or greater than the third reference temperature T3 (? S1? T3; YES in step 402), the air conditioner control section 30 performs determination as to which of the efficiency priority operation and the capability priority operation is to be executed. More specifically, the air conditioner control unit 30 determines whether the air conditioner 100 is in a predetermined operating condition (step 404).

Examples of the predetermined operating conditions include a case in which the heating operation is performed at a low outdoor air temperature, a case in which the power consumption in the compressor 201 is high, such as a case where the air conditioner 100 is started, .

When the air conditioner 100 corresponds to a predetermined operating condition (YES in step 404), the power priority operation is performed based on the control by the air conditioner control unit 30 (step 405).

In the power priority operation, the air conditioner control section 30 controls the air-conditioning control section 30 so that the temperature difference? S2 (= Sc-Sa) obtained by subtracting the inlet temperature Sa from the supercooling temperature Sc is less than a fourth reference temperature T4 (? Thereby controlling the opening of the valve 215. Here, the fourth reference temperature T4 is a constant of the optimum temperature difference between the refrigerant flowing through the first pipe 81 and the refrigerant flowing through the second pipe 82 in the supercooler 30. [ The fourth reference temperature T4 is set in the range of, for example, 10 to 20 占 폚.

More specifically, when performing the power priority operation, the air conditioner control section 30 acquires the inlet temperature Sa and the supercooling temperature Sc. Then, the temperature difference? S2 obtained by subtracting the inlet temperature Sa from the supercooling temperature Sc is compared with the fourth reference temperature T4.

In the capability priority operation, the air conditioner control unit 30 performs control to increase the opening degree of the supercooling reducing valve 215 when the temperature difference? S2 becomes equal to or higher than the fourth reference temperature T4 (? S2? T4). As a result, the amount of refrigerant passing through the supercooling reducing valve 215 increases, and the pressure after passing through the supercooling reducing valve 215 rises relatively. As a result, the temperature difference? S2 decreases and the temperature difference? S2 remains below the fourth reference temperature T4 (? S2 <T4).

19 is a diagram showing the relationship between the opening degree of the supercooling reducing valve 215, the amount of refrigerant sucked into the compressor 201, and the system efficiency of the air conditioner 100.

In the capability priority operation, the opening degree of the supercooling pressure reducing valve 215 is controlled such that the temperature difference? S2 is less than the fourth reference temperature T4 (? S2 <T4). 19, the amount of the refrigerant passing through the supercooling reducing valve 215 and the second pipe 82 and discharged to the injection path 24 is lower than that in the efficiency first operation . Then, the amount of the refrigerant sucked into the intermediate pressure suction portion 201c of the compressor 201 through the injection path 24 increases. The amount of the refrigerant sucked into the intermediate pressure suction portion 201c of the compressor 201 is increased so that the amount of the refrigerant flowing through the indoor heat exchanger 104 (the outdoor heat exchanger 102 at the time of heating operation) The amount decreases.

The amount of the refrigerant sucked into the intermediate pressure suction portion 201c of the compressor 201 is increased so that the amount of the refrigerant flowing through the indoor heat exchanger 104 (the outdoor heat exchanger 102 at the time of heating operation) The amount decreases. Accordingly, when the power priority operation is performed, the pressure loss in the indoor heat exchanger 104 or the outdoor heat exchanger 102 is reduced.

The amount of the refrigerant sucked into the intermediate pressure suction portion 201c of the compressor 201 is increased so that the refrigerant compressed in the low pressure side (between the suction portion and the intermediate pressure suction portion 201c) . As a result, the amount of work on the low-pressure side of the compressor 201 is reduced.

From the above, by performing the power priority operation in the air conditioner 100, the air conditioning ability is improved. As a result, for example, even in an operating condition in which power consumption in the compressor 201 is likely to be high, air conditioning can be performed more quickly in a user-desired environment.

On the other hand, when the operation state of the air conditioner 100 does not correspond to the predetermined operation state (NO in step 404), the efficiency priority operation is performed based on the control by the air conditioner control section 30 406).

In the efficiency first operation, the air conditioner control unit 30 controls the supercooling pressure reducing valve 215 (= Sc-Sa) so that the temperature difference? S2 (= Sc-Sa) obtained by subtracting the inlet temperature Sa from the supercooling temperature Sc becomes equal to or higher than the fourth reference temperature T4 ).

Specifically, when performing the efficiency-first operation, the air conditioner control unit 30 acquires the inlet temperature Sa and the supercooling temperature Sc, as in the capability priority operation. Then, the temperature difference? S2 obtained by subtracting the inlet temperature Sa from the supercooling temperature Sc is compared with the fourth reference temperature T4. In the efficiency first operation, the air conditioner control unit 30 performs control to reduce the opening degree of the supercooling reducing valve 215 when the temperature difference? S2 becomes less than the fourth reference temperature (? S2 <T4). As a result, the refrigerant passing through the supercooling reducing valve 215 is further depressurized. As a result, the inlet temperature Sa is lowered, the temperature difference? S2 is increased, and the temperature difference? S2 is maintained at the fourth reference temperature or higher (? S2? T4).

In this way, in the efficiency-first operation, the temperature difference? S2 is maintained at the fourth reference temperature or higher (? S2? T4), so that the refrigerant flowing through the first pipe 81 and the second pipe 82 The average temperature difference of the refrigerant flowing becomes large. Therefore, in the efficiency-first operation, the heat exchange efficiency in the supercooler 80 is improved and the refrigerant flowing in the first pipe 81 can be further supercooled as compared with the capability priority operation. As a result, in the efficiency priority operation, as shown in Fig. 19, the system efficiency in the air conditioner 1 is improved as compared with the capability priority operation.

Here, as in the first embodiment, the air conditioner 100 of the present embodiment has a receiver 218 that stores surplus refrigerant in a supercooled state.

Accordingly, in the air conditioner 100 of the present embodiment, for example, during the cooling operation, the remaining refrigerant after the surplus refrigerant is stored in the receiver 218 is sucked into the supercooler 80. [ That is, in the air conditioner 100 of the present embodiment, the flow rate of the refrigerant sucked into the first pipe 81 of the supercooler 80 at the time of the cooling operation becomes smaller as compared with the case where the receiver 218 is not provided .

Therefore, as compared with the case where the air conditioner 100 does not have the receiver 218, the pressure loss caused to the subcooler 80 is reduced. As a result, the lowering of the heat exchange efficiency in the supercooler 80 is further suppressed.

On the other hand, the present embodiment is also applicable to the air conditioner 100 having no receiver 218. That is, as described above, in the present embodiment, the supercooler 80 can supercool the refrigerant. Accordingly, in the present embodiment, even when the receiver 218 is not provided, the refrigerant before it is sucked into one of the first expansion valves 204a or the other first expansion valve 204b can be supercooled.

However, it is preferable that the air conditioner 100 has a receiver 218 from the viewpoint of performing the cooling operation and the heating operation with the optimum amount of refrigerant in the air conditioner 100.

In the air conditioner 100 of the present embodiment, the bridging circuit 23 having the first check valve 231 to the fourth check valve 234 is provided, 81 and the second piping 82 as countercurrent flows. However, the means for making the refrigerant flowing in the first piping 81 and the second piping 82 countercurrent in the subcooler 80 is not limited to this. For example, refrigerant flowing through the first piping 81 and the second piping 82 may be countercurrent by switching the flow direction of the refrigerant using an electronic switching valve or the like.

&Lt; Sixth Embodiment &

Hereinafter, a sixth embodiment of the present invention will be described with reference to the drawings.

20, the air conditioner 100 of the present embodiment includes, in addition to the configuration of the fourth embodiment or the fifth embodiment, a refrigerant quantity detecting mechanism (for example, Z).

Specifically, as shown in Fig. 21, the refrigerant amount detection mechanism Z includes a plurality of derivation paths Z1 connected to a plurality of different height positions of the receiver 218; A fluid resistance Z2 such as a plurality of capillaries provided in each of the plurality of lead-out paths Z1; A plurality of temperature sensors (Z3) provided on the downstream side of the fluid resistance (Z2) in the plurality of derivation paths (Z1); And a refrigerant amount detection unit (Z4) for detecting the amount of refrigerant in the receiver (218) by using the refrigerant temperature obtained by the plurality of temperature sensors (Z3).

The collecting tube portion Z1x (corresponding to the connection path 20b) formed in the plurality of lead-out paths Z1 is connected to the low-pressure pipe 20s of the refrigerant circuit 20. [

The refrigerant amount detection unit Z4 is configured by the refrigerant amount detection unit 41 of the above embodiment.

Specifically, the refrigerant amount detection unit 41 detects the detected temperatures of the plurality of temperature sensors Z3, and detects the refrigerant amount in the receiver 218 by using the magnitude relationship of the detected temperatures of the respective temperature sensors. Here, among the plurality of derived paths Z1, the detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the liquid portion and the detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the gas- It is possible to distinguish between the derivation furnace Z1 through which the liquid refrigerant passes and the derivation furnace Z1 which does not. Thus, the amount of refrigerant in the receiver 218 can be detected.

In addition, as shown in Fig. 22, the refrigerant amount detecting mechanism Z includes a plurality of lead-out paths Z1 connected to a plurality of different height positions of the receiver 218; A fluid resistance Z2 such as a plurality of capillaries provided in each of the plurality of lead-out paths Z1; A plurality of solenoid valves (Z5) provided on the downstream side of the fluid resistance (Z2) in the plurality of derived paths (Z1); A temperature sensor Z6 provided in the collecting tube portion Z1x of the plurality of lead-out paths Z1; And a refrigerant amount detection unit (Z4) for detecting the amount of refrigerant in the receiver (218) by using the refrigerant temperature obtained by the temperature sensor (Z6).

The collecting tube portion Z1x (corresponding to the connection path 20b) formed in the plurality of lead-out paths Z1 is connected to the low-pressure pipe 20s of the refrigerant circuit 20. [

The refrigerant amount detection unit Z4 is configured by the refrigerant amount detection unit 41 of the above embodiment.

Specifically, the refrigerant amount detection unit 41 controls the opening and closing of the plurality of solenoid valves Z5 so as to communicate each of the outflow paths, and acquires the detected temperature of the temperature sensor Z6 obtained at this time. The detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the liquid portion and the detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the gas- It is possible to distinguish between the derivation furnace Z1 through which the liquid refrigerant passes and the derivation furnace Z1 which does not. Thus, the amount of refrigerant in the receiver 218 can be detected.

&Lt; Seventh Embodiment &

Hereinafter, a seventh embodiment of the present invention will be described with reference to the drawings.

As shown in Fig. 23, the air conditioner 100 of the seventh embodiment includes an outdoor unit 10 installed outside the building; An indoor unit (11) installed in the building; A refrigerant circuit (20) constituted by connecting the outdoor unit (100) and the indoor unit (11) with a refrigerant pipe (12); And an air conditioner control unit 30 for controlling the outdoor unit 100 and the indoor unit 11 to perform air conditioning operation.

The refrigerant circuit 20 is connected to the compressor 201, the four-way switching valve 202, the condenser (outdoor heat exchanger) 203, the first expansion valve 204 and the evaporator (indoor heat exchanger) . In this embodiment, the compressor 201, the four-way switching valve 202, the condenser 203, and the first expansion valve 204 are installed inside the outdoor unit 10 and the evaporator 205 is connected to the indoor unit 11, As shown in Fig. On the other hand, the outdoor unit 10 compresses the refrigerant vaporized by the evaporator 205 in the indoor unit 11 and cools it. Further, the indoor unit 11 performs heat exchange between the room air and the refrigerant in the evaporator 205, cools the room air, and evaporates the refrigerant.

The compressor (201) compresses the vaporized refrigerant gas introduced at the inlet of the low pressure side to generate a high temperature and high pressure compressed gas. The compressor 201 is driven by a motor capable of controlling the rotation speed, and the compression ability is changed in accordance with the rotation speed of the motor. That is, the compression capability is high when the rotation speed of the motor is high, and the compression ability is low when the rotation speed of the motor is low. The compressor 201 controls the rotational speed of the motor by a compressor control unit 301, which will be described later. The compressor 201 sends the generated high-temperature and high-pressure compressed gas to the condenser 203 through the four-way switching valve 202.

The condenser 203 condenses the compressed gas generated by the compressor 201 through a heat exchanger. The condenser 203 performs heat exchange between the high temperature compressed gas and the low temperature outdoor air, and generates liquid refrigerant. Then, the condenser 203 delivers the liquid refrigerant generated by the heat exchange to the first expansion valve 204.

The first expansion valve (204) is a valve that adjusts a flow rate flowing through the first expansion valve (204) by opening and closing. Here, the first expansion valve (204) is opened / closed by the first expansion valve control section (302). By opening the first expansion valve (204), the liquid refrigerant expands and evaporates to become refrigerant gas. This refrigerant gas is lower in temperature than the liquid refrigerant before it flows into the first expansion valve (204). The first expansion valve 204 controls the degree of opening (degree of opening) indicating the degree of opening thereof in accordance with a signal output from the first expansion valve control section 302, which will be described later. Then, the first expansion valve (204) delivers the refrigerant gas to the evaporator (205).

The evaporator 205 performs heat exchange between the refrigerant gas generated in the first expansion valve 204 and the room air at a high temperature. The evaporator 205 cools the room air and vaporizes part of the refrigerant. The gas-liquid two-phase refrigerant generated in the evaporator 205 is sent to the compressor 201 through the four-way switching valve 202.

The refrigerant pipe 12 has a first refrigerant pipe 121 which is a gas-side refrigerant pipe and a second refrigerant pipe 122 which is a liquid-side refrigerant pipe. The first refrigerant pipe 121 connects the evaporator 205 of the indoor unit 11 and the four-way valve 202 of the outdoor unit 10. The second refrigerant pipe 122 connects the condenser 203 (the first expansion valve 204) of the outdoor unit 10 and the evaporator 205 of the indoor unit.

In addition, the outdoor unit fan 10F is installed in the outdoor unit 10 and the indoor unit fan 11F is installed in the indoor unit 11.

The outdoor fan (10F) blows to the condenser (203) to cool the refrigerant. The outdoor fan 10F is controlled by the outdoor fan control unit 303, which will be described later.

The indoor fan (11F) cools the room air in the evaporator (205) and blows the cooled air into the room. The rotation speed of the indoor fan 11F is controlled by the indoor fan control unit 304 described later.

A discharge temperature sensor 206, an intake temperature sensor 207, an outlet temperature sensor 208, a liquid pipe temperature sensor 209, a high pressure sensor 210 and a low pressure sensor 211 are installed in the refrigerant circuit 20 .

The discharge temperature sensor 206 detects the refrigerant temperature (discharge temperature Td) at the high pressure side of the compressor 201 and outputs a signal indicating the detected discharge temperature to the A / D converter 50. On the other hand, the A / D conversion unit 50 may be provided in the air conditioner control unit 30 and may be provided in the refrigerant quantity detection device 40 described later.

The suction temperature sensor 207 detects the refrigerant temperature (suction temperature Tsuc) at the low-pressure side of the compressor 201 and outputs a signal indicating the detected suction temperature to the A / D converter 50. [

The outlet temperature sensor 208 detects the refrigerant temperature (outlet temperature Tcond (first refrigerant temperature)) at the outlet of the condenser 203 and outputs a signal indicating the detected outlet temperature to the A / D converter 50 do. On the other hand, the outlet temperature sensor 208 is installed in the heat transfer pipe on the outlet side of the condenser 203.

The liquid pipe temperature sensor 209 detects the refrigerant temperature (liquid pipe temperature Tsub (second refrigerant temperature)) on the downstream side of the first expansion valve 204 installed on the outlet side of the condenser 203, To the A / D converter 50. The A / On the other hand, the liquid pipe temperature sensor 209 is provided in the liquid pipe 212. The liquid pipe 212 is a pipe connecting the outlet of the condenser 203 and the inlet of the evaporator 205.

The high pressure sensor 210 detects the pressure (high pressure side pressure Pd) on the high pressure side of the compressor 201 and outputs a signal indicating the detected high pressure side pressure to the A / D conversion section 50.

The low pressure sensor 211 detects the pressure on the low pressure side of the compressor 201 (low pressure side pressure Ps) and outputs a signal indicating the detected low pressure side pressure to the A / D converter 50.

The air conditioner control unit 30 controls each component of the air conditioner 100. On the other hand, although the air conditioner control unit 30 is connected to the components of the indoor unit 11 and the outdoor unit 10, the description of the connection is omitted in Fig. The details of the air conditioner control unit 30 will be described later with reference to Fig.

However, the refrigerant piping 12 (the first refrigerant piping 121 and the second refrigerant piping 122) of the air conditioner 100 of this embodiment is provided separately from the air conditioner 100, 13 are installed. The auxiliary unit (13) is detachably connected to the refrigerant pipe (12). Here, the pipe diameters of the inner pipes (the first inner pipe 131 and the second inner pipe 132) of the auxiliary unit 13 connected to the refrigerant pipe 12 are larger than the pipe diameter of the refrigerant pipe 12 .

The auxiliary unit 13 includes a first trapping device 13a and a second trapping device 13b for trapping impurities in the refrigerant flowing through the refrigerant pipe 12; And a refrigerant quantity detecting device (40) for detecting the refrigerant quantity in the refrigerant circuit (20).

The first trapping device 13a is installed on a first internal piping 131 detachably attached to the first refrigerant piping 121. The first trapping device 13a is connected to the first branch piping 131 for branching the first internal piping 131 into two, A connection pipe 13a3 connecting the first branched pipe 13a1 and the second branched pipe 13a2 to the first branched pipe 13a1 and the second branched pipe 13a2; And a catching member 13a4 for catching a predetermined substance of the refrigerant flowing through the refrigerant pipe 13a. On the other hand, the first branch piping 13a1 and the second branch piping 13a2 join together on the downstream side.

The second capturing device 13b is installed on a second internal piping 132 detachably attached to the second refrigerant piping 122 and is connected to the first branch piping 132 branched from the second internal piping 132, A connection pipe 13b3 connecting the first branch pipe 13b1 and the second branch pipe 13b2 and a connection pipe 13b2 provided on the connection pipe 13b3 and connecting pipes 13b1 and 13b2, And a catching member 13a4 for catching a predetermined substance of the refrigerant flowing through the refrigerant pipe 13a. On the other hand, the first branch pipe 13b1 and the second branch pipe 13b2 join on the downstream side.

The trapping members 13a4 and 13a4 are replaced with the first indoor unit 11 and the outdoor unit 11 newly installed from the existing indoor unit and the outdoor unit and the oxidation scale at the time of piping welding in the refrigerant, A refrigerator oil or sludge used in a compressor of an existing outdoor unit is captured. In the present embodiment, a filter is used.

The refrigerant amount detection device (40) detects the amount of refrigerant in the refrigerant circuit in the air conditioner (100). On the other hand, although the refrigerant quantity detecting device 40 is connected to the components of the indoor unit 11 and the outdoor unit 10, the description of the connection is omitted in Fig. Details of the refrigerant amount detection device 40 will be described later with reference to Fig.

24 is a schematic block diagram showing the configuration of the refrigerant amount detection device 40 according to the present embodiment. On the other hand, the A / D converter 50 analog-to-digital converts the signals received from the sensors 206 to 211, and outputs the converted signals to the refrigerant amount detecting unit 41. [ The input unit 60 outputs detection start information or the like indicating that the refrigerant amount is to be detected to the control unit 411 based on the user's operation. The display unit 70 is a display unit for displaying information such as a digital display panel by an LED, for example, and displays information on the refrigerant amount ratio input by the refrigerant amount averaging unit 414 described later.

Specifically, the refrigerant amount detection device 40 includes a storage unit 42 for storing a refrigerant amount detection unit 41 for determining a refrigerant state, a refrigerant amount detection unit 41 for calculating a refrigerant amount ratio, a parameter used for calculating a refrigerant amount ratio, Respectively.

The refrigerant amount detection unit 41 calculates the refrigerant amount ratio on the basis of the temperature and pressure information input from the A / D conversion unit 50, and outputs information on the calculated refrigerant amount ratio to the display unit 70. [ Here, the refrigerant amount ratio is a value ("actual refrigerant amount" / "specified refrigerant amount") obtained by actually dividing the amount of the refrigerant in the air conditioner 100 by the amount of the refrigerant specified as the specification for the air conditioner 100.

The refrigerant amount detection unit 41 has a control unit 411, a refrigerant state acquisition unit 412, a refrigerant amount calculation unit 413, and a refrigerant amount average calculation unit 414.

The control unit 411 receives detection start information indicating that the detection of the refrigerant amount ratio of the air conditioner 100 is started from the input unit 60. [ Further, the control unit 411 outputs to the air conditioner control unit 30 an instruction to perform the operation in the predetermined operation mode which is the cooling operation. The control unit 411 outputs an operation termination command for terminating the operation to the air conditioner control unit 30. [

On the other hand, the air conditioner control unit 30 includes a compressor control unit 301 for controlling the rotation speed of the motor of the compressor 201 based on a command input from the control unit 411; A first expansion valve control section (302) for controlling the opening degree of the first expansion valve (204); An outdoor fan control unit 303 for controlling the rotation speed of the outdoor fan 10F and an indoor fan control unit 304 for controlling the rotation speed of the indoor fan 11F.

More specifically, the air conditioner control unit 30 controls the superheating degree SH of the evaporator 205 provided in the indoor unit 11 to be constant (for example, 3 K). The superheat degree is obtained by subtracting the saturation temperature at the evaporation temperature from the refrigerant temperature at the outlet of the evaporator 205, that is, subtracting the saturation temperature at the low pressure side of the compressor 201 from the refrigerant temperature at the low pressure side of the compressor 201 will be. The first expansion valve control unit 302 controls the degree of superheat of the evaporator 205 to be constant by adjusting the opening degree of the first expansion valve 204. The control unit 411 also outputs to the compressor control unit 301 a command to operate the rotation speed of the motor of the compressor 201 at a predetermined rotation speed (for example, 65 Hz). The compressor control unit 301 receives a command from the control unit 411 to cause the motor 201 to rotate at a predetermined rotational speed (for example, 65 Hz) Hz.

The control unit 411 outputs to the outdoor fan control unit 303 an instruction to cause the outdoor fan 10F to operate at a constant speed. The outdoor fan control unit 303 causes the outdoor fan 10F to operate at a constant speed.

The control unit 411 outputs to the indoor fan control unit 304 a command to control the indoor fan 11F at a constant speed. The indoor fan control unit 304 causes the indoor fan 11F to operate at a constant speed.

Further, the control unit 411 outputs a command to the refrigerant state acquisition unit 412 and the refrigerant amount calculation unit 413 to calculate the refrigerant amount ratio. The control unit 411 receives from the refrigerant amount average calculation unit 414 an average value calculation end signal indicating that the calculation of the average value of the refrigerant amount ratios is completed. The control unit 411 outputs an operation end signal to the air conditioner control unit 30 when the average value calculation end signal is inputted from the refrigerant amount average calculation unit 414. [

The refrigerant state acquisition section 412 determines whether or not the refrigerant state at the outlet of the condenser 203 is the supercooled state after the air conditioner control section 30 starts the operation of the air conditioner 100 in the predetermined operation mode Liquid two-phase state. The refrigerant state acquisition section 412 determines that the refrigerant state is one of the supercooled state or the vapor-liquid two-phase state, using the outlet temperature Tcond indicated by the outlet temperature signal and the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal as parameters. Then, this discrimination signal is outputted to the refrigerant quantity calculation section 413. [

Details are as follows.

Tcond-Tsub? X, it is determined that the refrigerant state is the "supercooled state ".

When Tcond-Tsub > X, the refrigerant state is judged as "gas-liquid two-phase state ".

Here, X is a constant and is a value (for example, X = 1.5) obtained in advance using the measured data.

The refrigerant amount calculation unit 413 calculates the refrigerant amount ratio in the air conditioner 100 by using different calculation equations according to the refrigerant state acquired by the refrigerant state acquisition unit 412. [

More specifically, the coolant amount calculation unit 413 calculates the coolant amount ratio RA by using the supercooled state calculation formula when the supercooled state is in the supercooled state, and calculates the coolant amount ratio RA by using the vapor-liquid two- do.

The calculation formula for the supercooled state is as follows.

RA = a1 + b1 x Pd + c1 x Ps + d1 x Tsub + e1 x Td

Here, the constants a1, b1, c1, d1 and e1 are values obtained in advance by multiple regression calculation using the actual data showing the relationship between Pd, Ps, Tsub, Td and RA in the supercooled state. On the other hand, the constants a1, b1, c1, d1 and e1 are recorded in the calculation parameter storage section 421 set in the storage section 42. [

The equation for the vapor-liquid two-phase state is as follows.

RA = a2 + b2 x Pd + c2 x Ps + d2 x Tsub + e2 x Td

Here, the constants a2, b2, c2, d2 and e2 are values obtained in advance by multiple regression calculation using the actual data showing the relationship between Pd, Ps, Tsub, Td and RA in the vapor-liquid two- On the other hand, the constants a2, b2, c2, d2, and e2 are recorded in the calculation parameter storage unit 421.

The refrigerant quantity calculation section 413 reads the constants a1, b1, c1, d1, e1 or constants a2, b2, c2, d2, e2 in accordance with the refrigerant state acquired by the refrigerant state acquisition section 412.

Further, the coolant amount calculation section 413 calculates the coolant amount based on the discharge pressure Pd indicated by the discharge pressure signal and the suction pressure Ps indicated by the suction pressure signal, the liquid pipe temperature Tsub indicated by the liquid pipe temperature signal, and the discharge temperature Td indicated by the discharge temperature signal, The refrigerant quantity ratio RA is calculated by an equation corresponding to the state. The coolant amount calculation unit 413 records the coolant amount ratio data indicating the calculated coolant amount ratio RA in the coolant amount storage unit 422 set in the storage unit 42. [

The refrigerant amount calculation unit 414 reads the refrigerant amount ratio RA calculated within a predetermined time (for example, past five minutes) from the refrigerant amount calculation unit 413. The refrigerant amount average calculation unit 414 calculates an average value of the read refrigerant amount ratio RA and outputs the calculated average value of the refrigerant amount ratio RA to the display unit 70. [ When the calculation of the average value of the refrigerant amount ratio RA is ended, the refrigerant amount average calculation unit 414 outputs to the control unit 411 a calculation end signal indicating that the calculation of the average value of the refrigerant amount ratio RA is ended.

According to the auxiliary unit 13 of the present embodiment configured as described above, it is possible to detect the amount of refrigerant in the air conditioner 100 by attaching the air conditioner 100 to the existing air conditioner 100 separately. Here, when the refrigerant state is the supercooling state, the calculation formula for the supercooling state is used, and when the refrigerant state is the vapor-liquid two-phase state, the equation for the gas-liquid two- The amount of refrigerant can be detected with high accuracy. Therefore, the refrigerant amount ratio can be accurately detected without being affected by installation conditions such as when using a long piping or when there is a large difference in height between the outdoor unit 10 and the indoor unit 11.

According to the present embodiment, the control section 411 fixes the opening degree of the second expansion valve 215 at a predetermined value. Accordingly, the degree of cooling of the liquid refrigerant in the liquid pipe 212 can be made constant, and the refrigerant amount ratio can be detected with high precision.

Further, according to the present embodiment, the control unit 411 fixes the compression capacity of the compressor 201 to a predetermined value. Accordingly, in the present embodiment, the state of the refrigerant at the inlet and the outlet of the compressor 201 can be made constant, and the refrigerant amount ratio can be detected with high precision.

Further, according to the present embodiment, the control section 411 fixes the opening degree of the first expansion valve 204 to a predetermined value. Accordingly, in the present embodiment, the cooling degree in the first expansion valve 204 can be made constant, and the refrigerant amount ratio can be detected with high precision.

Further, according to the present embodiment, the controller 411 fixes the rotational speed of the outdoor fan 10F and the rotational speed of the indoor fan 11F to predetermined values. Accordingly, in the present embodiment, the degree of heat exchange in the condenser 203 can be made constant, the degree of heat exchange in the evaporator 205 can be made constant, and the refrigerant amount ratio can be detected with high precision.

According to the present embodiment, since the auxiliary unit 13 is provided separately from the air conditioner 100 and detachably attached to the first refrigerant pipe 121 and the second refrigerant pipe 122, Since the unit 13 has versatility and the auxiliary unit 13 has the first and second capture devices 13a and 13b for capturing refrigerator oil, sludge, oxide scale, etc. in the coolant, It is possible to eliminate the inconvenience caused when refrigerant is exchanged in a plurality of outdoor units 10 by one auxiliary unit 13 and it is not necessary to manufacture an outdoor unit dedicated for refrigerant exchange and deterioration of productivity can be prevented. Here, when the catching members 13a4 and 13b4 are exchanged, the auxiliary unit 13 can be separated from the refrigerant pipe 12 and can be easily maintained.

Even if the refrigerant is switched to the cooling operation and the heating operation and the refrigerant is directed from the first branch pipes 13a1 and 13b1 to the second branch pipes 13a2 and 13b2, the second branch pipes 13a2 and 13b2, The direction of flow of the connection pipes 13a3 and 13b3 can be the same even when they are directed to the pipes 13a1 and 13b1. Since the trapping members 13a4 and 13b4 are provided in the connection pipes 13a3 and 13b3, the flow direction of the refrigerant flowing through the trapping members 13a4 and 13b4 is constant and the trapped members 13a4 and 13b4 It is possible to prevent the refrigerant from flowing back to the refrigerant pipe 12 again.

&Lt; Embodiment 8 >

Next, the auxiliary unit 13 of the eighth embodiment will be described with reference to the drawings.

In the seventh embodiment, the amount of refrigerant in the air conditioner 100 can be accurately measured. However, in the present embodiment, when the refrigerant is supplemented, %, A display prompting the person performing the operation to urge the operation of the refrigerant injection valve 216 is performed.

25 is a schematic block diagram showing the configuration of the air conditioner 100 and the auxiliary unit 13 according to the eighth embodiment.

The auxiliary unit 13 of the present embodiment further includes a refrigerant supply device comprising a refrigerant injection valve (charge valve) 216 and a refrigerant storage container 217. [ The refrigerant supply device is connected to the second internal pipe 132 and supplies the refrigerant to the second internal pipe 132.

The refrigerant injection valve 216 is a valve that is opened or closed by a person performing the operation in order to supplement the refrigerant in accordance with an instruction given by the display unit 70.

The refrigerant storage container 217 is a container for storing the refrigerant to be replenished.

26 is a schematic block diagram showing the configuration of the refrigerant amount detection device 40 according to the present embodiment.

The configuration of the refrigerant quantity detection device 40 of the present embodiment is the same as the configuration of the refrigerant quantity detection device 40 except that the refrigerant quantity determination section 415 is newly added and the refrigerant quantity averaging section 414 and the control section 411 have a new function. Is the same as the configuration of the refrigerant amount detection device 40 (Fig. 24) in the embodiment. Therefore, explanations of the refrigerant amount calculation section 414, the refrigerant amount determination section 415, and the control section 411 will be omitted.

The coolant amount average calculation section 414 reads the coolant amount ratio calculated from the coolant amount storage section 422 within a predetermined time (for example, past five minutes). The refrigerant amount calculation section 414 calculates the moving average value of the read refrigerant amount ratio and outputs the calculated moving average value to the refrigerant amount determination section 415. [

The refrigerant amount determining section 415 determines whether or not the moving average value of the refrigerant amount ratio exceeds 100% based on the moving average value of the refrigerant amount ratio inputted from the refrigerant amount averaging calculation section 414. When the refrigerant amount determining section 415 determines that the moving average value of the refrigerant amount ratio exceeds 100%, the refrigerant amount determining section 415 outputs a charging end signal to the control section 411. [

The control unit 411 causes the display unit 70 to open the refrigerant injection valve 216 on the basis of the input of the detection start information from the input unit 60 and the input of the charge end signal from the refrigerant amount determination unit 415 Quot ;, "close ", or" close "

On the other hand, the operation of the refrigerant amount detection device 40 of the present embodiment is the same as that of the refrigerant amount detection device of the third embodiment (see Fig. 8).

As described above, according to the present embodiment, the air conditioner 100 is provided with the refrigerant injection valve 216 for filling the air conditioner 100 with the refrigerant. In accordance with the judgment of the refrigerant amount determination section 415, An instruction to close the valve 216 is displayed on the display unit 70. [ Accordingly, in the present embodiment, when the detection of the refrigerant amount ratio is started to the person performing the operation, the refrigerant injection valve 216 is opened, and when the refrigerant amount ratio becomes 100% or more, the refrigerant injection valve 216 So that the refrigerant can be replenished reliably.

In the present embodiment, the refrigerant injection valve 216 is opened and closed by a person who performs the operation, but the control unit 411 controls the refrigerant injection valve 216 through the air conditioner control unit 30 , It may be automatically opened and closed.

On the other hand, in each of the above-described embodiments, the reliability of the compressor 201 continues to be protected. In the case of entering the protection zone (each measured value of the discharge temperature, overcurrent, high pressure and low pressure is the minimum physical quantity ), The operation of the air conditioner 100 may be stopped and the "detection failure" may be displayed on the display unit 70.

&Lt; Ninth Embodiment &

Hereinafter, a ninth embodiment of the present invention will be described with reference to the drawings.

The auxiliary unit 13 of the present embodiment includes a refrigerant storage portion for storing the surplus refrigerant of the refrigerant circuit 20 in addition to the configuration of the eighth embodiment.

Specifically, as shown in Fig. 27, the auxiliary unit 13 includes a receiver 218 as an example of a refrigerant storage portion for storing surplus refrigerant; And a receiver pressure reducing valve 219 as an example of a flow rate adjusting unit for reducing the pressure of the refrigerant flowing out of the receiver 218 and adjusting the flow rate of the refrigerant.

The opening degree of the receiver pressure reducing valve 219 of this embodiment is controlled by the control of the air conditioner control section 30 so that the amount and pressure of the refrigerant passing through the receiver pressure reducing valve 219 are adjusted.

The branch path 20a is branched from the refrigerant circuit 20 in the piping between the condenser (outdoor heat exchanger) 102 and the first expansion valve 103 (the second internal piping 132). The above-described receiver 218 is connected to the end of the branch path 20a. In addition, the above-described receiver pressure reducing valve 219 is provided in the branch passage 20a.

The receiver 218 of the present embodiment is formed of a material having heat conductivity such as iron. The receiver 218 has a cylindrical shape, for example, and is installed vertically in the outdoor unit 10. The receiver 218 is formed with a connecting portion to which the terminating end of the branch passage 20a is connected. In other words, in the receiver 218 of the present embodiment, the refrigerant flows in and out of the connection portion provided at the lower portion of the vertical direction.

The receiver 218 stores surplus refrigerant during cooling operation and defrost operation. Further, the receiver 218 supplies the refrigerant stored in the cooling operation mode or the defrosting operation mode to the refrigerant circuit 20 during the heating operation. In other words, in the air conditioner 100 of the present embodiment, the amount of the refrigerant circulating in the refrigerant circuit 20 is adjusted by the receiver 218. [

On the other hand, it is preferable that the volume of the receiver 218 is set so that the amount of refrigerant obtained by subtracting the optimum amount of refrigerant at the time of cooling operation from the optimum amount of refrigerant at the time of heating operation is equal to the volume converted into the supercooled liquid state. Here, the optimum amount of refrigerant means the amount of refrigerant in which the system efficiency of the heating operation and the cooling operation is the highest in the air conditioner 100. Although the details will be described later, the refrigerant circuit 20 is filled with the refrigerant having the optimum amount of refrigerant at the time of heating operation in the air conditioner 100 of the present embodiment. Therefore, when the volume of the receiver 218 is set as described above, the surplus refrigerant is received in the receiver 218 during the cooling operation, so that the cooling operation is performed with the optimum amount of refrigerant. Also, the size of the receiver 218 is suppressed.

However, the auxiliary unit 13 of the present embodiment has the refrigerant amount detection mechanism Z for detecting the amount of refrigerant in the receiver 218 which is the refrigerant storage portion.

Specifically, as shown in Fig. 28, the refrigerant amount detecting mechanism Z includes a plurality of deriving paths Z1 connected to a plurality of different height positions of the receiver 218; A fluid resistance Z2 such as a plurality of capillaries provided in each of the plurality of lead-out paths Z1; A plurality of temperature sensors (Z3) provided on the downstream side of the fluid resistance (Z2) in the plurality of derivation paths (Z1); And a refrigerant amount detection unit (Z4) for detecting the amount of refrigerant in the receiver (218) by using the refrigerant temperature obtained by the plurality of temperature sensors (Z3).

The collecting tube portion Z1x formed in the plurality of lead-out paths Z1 is connected to the first internal pipe 131. [ On the other hand, the condensing tube section Z1x is provided with a connection opening / closing valve 220, which is opened / closed by the connection opening / closing valve 220.

The refrigerant amount detection unit Z4 is configured by the refrigerant amount detection unit 41 of the above embodiment.

Specifically, the refrigerant amount detection unit 41 detects the detected temperatures of the plurality of temperature sensors Z3, and detects the refrigerant amount in the receiver 218 by using the magnitude relationship of the detected temperatures of the respective temperature sensors. Here, among the plurality of derived paths Z1, the detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the liquid portion and the detection temperature of the temperature sensor Z3 of the lead-out path Z1 connected to the gas- It is possible to distinguish between the derivation furnace Z1 through which the liquid refrigerant passes and the derivation furnace Z1 which does not. Thus, the amount of refrigerant in the receiver 218 can be detected.

As described above, according to the present embodiment, the amount of refrigerant in the air conditioner 100 can be detected by separately attaching the air conditioner 100 to the existing air conditioner 100. Since the refrigerant amount detection mechanism Z for detecting the refrigerant amount in the refrigerant storage portion 218 is provided, the amount of refrigerant in the refrigerant storage portion 218, regardless of the refrigerant state at the outlet of the outdoor heat exchanger 203, In addition, the amount of refrigerant in the air conditioner 100 (refrigerant circuit 20) can be accurately detected.

On the other hand, in the above-described example, the air conditioner 1 having the receiver pressure reducing valve 219 as an example of the flow rate adjusting means has been described. However, the flow rate regulating means is not limited to the pressure reducing valve. For example, an opening / closing valve, a flow rate control valve, or the like may be used as the flow rate regulating means. In this case, the flow rate of the refrigerant discharged from the receiver 218 to the refrigerant circuit 20 through the branch passage 20a and the speed of the refrigerant can be adjusted.

The refrigerant amount detection mechanism Z may be configured as shown in Fig. 22 of the sixth embodiment.

In the ninth embodiment, the auxiliary unit 13 has the refrigerant amount detection device 40, and detects the amount of refrigerant in the refrigerant circuit 20 by an arithmetic expression. In addition, the refrigerant amount detection mechanism (Z) The auxiliary unit may have only the refrigerant amount detection mechanism Z without detecting the amount of refrigerant in the refrigerant circuit 20 by using the calculation formula.

<Tenth Embodiment>

Hereinafter, a tenth embodiment of the present invention will be described with reference to the drawings.

29, the auxiliary unit 13 includes a gas side refrigerant pipe (a gas side internal pipe 131 detachably connected to the first refrigerant pipe 121, a liquid side refrigerant pipe A bypass pipe 133 connected to the gas-side internal piping 131 and the liquid-side internal piping 132, and a bypass pipe 133 connected to the liquid-side internal piping 132. The liquid- And an auxiliary heat exchanger (134) installed in the heat exchanger (133) and performing heat exchange with another heat source.

The gas-side internal piping 131 is connected between the first refrigerant piping 121 and connects the evaporator 205 of the indoor unit 11 and the four-way valve 202 of the outdoor unit 10. The liquid-side internal piping 132 is connected between the second refrigerant pipeline 122 and connects the condenser 203 (the first expansion valve 204) of the outdoor unit 10 and the evaporator 205 of the indoor unit .

The auxiliary heat exchanger 134 of the present embodiment performs heat exchange between the heater 13H which is another heat source and the refrigerant flowing through the bypass pipe 133. [ On the other hand, the heater 13H is installed in the auxiliary unit 13.

Here, Fig. 30 shows the type of the heater 13H and the structure of the auxiliary heat exchanger 134 for heating the refrigerant. 30A, when a heater capable of autonomously controlling the temperature is used as the heater 13H, for example, a PTC heater, the temperature can be maintained autonomously at a temperature at which the refrigerant does not deteriorate, for example, 150 DEG C or less Therefore, it is possible to construct a simple heat exchanger such as winding the heater 13H directly to the bypass pipe 133 (refrigerant pipe). On the other hand, as shown in Fig. 30B, when a heater which can not be autonomously controlled in temperature is used as the heater 13H, for example, an electric heater is used, the electric heater 13H and the bypass pipe 133 A heat pipe 134p is installed in the heat pipe 134c so that heat can not be heated beyond a predetermined temperature.

The bypass pipe 133 is provided with a flow rate adjusting valve (additional expansion valve) 135 for adjusting the amount of refrigerant flowing from the liquid pipe to the gas pipe side through the bypass pipe 133. On the other hand, the opening degree of the flow rate adjusting valve 135 is controlled by the sub-unit control section 13C.

An inlet temperature sensor 136 for detecting the temperature of the refrigerant flowing into the auxiliary heat exchanger 134 is provided at the inlet side of the auxiliary heat exchanger 134 in the bypass pipe 133. On the other hand, the inlet temperature sensor 136 outputs a signal indicating the detected inlet temperature to the sub-unit controller 13C.

An outlet temperature sensor 137 for detecting the temperature of the refrigerant flowing out of the auxiliary heat exchanger 133 is provided at the outlet side of the auxiliary heat exchanger 134 in the bypass pipe 133. On the other hand, the outlet temperature sensor 137 outputs a signal indicating the detected outlet temperature to the sub-unit control section 13C.

Next, the cooling operation of the air conditioner 100 to which the auxiliary unit 13 is connected will be described briefly together with the function of the auxiliary unit control unit 13C.

(1) During normal cooling operation

In the normal cooling operation, the sub-unit control section 13C outputs a closing signal to the flow regulating valve 135, and sets the flow regulating valve 135 to the closed state. Further, the sub-unit control section 13C turns off the heater 13H.

(2) During the cooling operation at low ambient temperature

The auxiliary unit control section 13C turns on the heater 13H to output an opening signal to the flow rate regulating valve 135. When the flow rate regulating valve 135 is in the open state do. At this time, the subsidiary unit control unit 13C acquires the inlet temperature from the inlet temperature sensor 136, obtains the outlet temperature from the outlet temperature sensor 137, (135).

According to the auxiliary unit 13 of this embodiment configured as described above, the bypass pipe 133 connected to the gas-side internal piping 131 and the liquid-side internal piping 132 is connected to the heater 13H, which is another heat source, A part of the liquid refrigerant flowing through the liquid side internal pipe 132 can be heated by the auxiliary heat exchanger 134 and supplied to the gas side internal pipe 131 because the auxiliary heat exchanger 134 that performs heat exchange is provided . Accordingly, the supply amount of the refrigerant to the indoor heat exchanger 205 and the outdoor heat exchanger 203 can be adjusted to adjust the heat exchange amount of the outdoor heat exchanger 203 and the heat exchange amount of the indoor heat exchanger 205 have. Therefore, it is possible to adjust the heat exchange amount of the outdoor heat exchanger 203 and the heat exchange amount of the indoor heat exchanger 205 in the cooling operation at the low outdoor air temperature, and to perform the cooling operation at the low outdoor air temperature without any problem . In addition, the function of the auxiliary unit 13 can be externally attached to the existing air conditioner 100, so that the function can be given to the existing air conditioner 100.

31, in addition to the heater 13H of the above-described embodiment, the other heat source of the tenth embodiment can be realized by using the heat pump 14, The heat transfer system 15 for transferring the heat transferred from the heat transfer system 15 may be used.

When the heat pump 14 shown in Fig. 31 is used, the high-temperature refrigerant is supplied to the auxiliary heat exchanger 135 by the heat pump 14 during the cooling operation at a low outside air temperature. Thus, in the auxiliary heat exchanger 135, heat exchange is performed between the high temperature refrigerant of the heat pump 14 and the refrigerant flowing through the bypass pipe 133. On the other hand, the sub-unit control unit 13C acquires the inlet temperature from the inlet temperature sensor 136, obtains the outlet temperature from the outlet temperature sensor 137, and controls the flow rate adjusting valve 135, respectively.

When the heat transfer system 15 shown in Fig. 32 is used, the high-temperature refrigerant is supplied to the auxiliary heat exchanger 135 by the heat transfer system 15 during the cooling operation at a low outside air temperature. On the other hand, the heat conveyance system 15 conveys renewable energy such as geothermal heat or solar heat, and has a circulation pump 151 for circulating the heating medium. The auxiliary unit control section 13C turns on the flow pump 151 so that the high temperature refrigerant is supplied to the auxiliary heat exchanger 135 by the heat transfer system 15. [ The auxiliary unit control section 13C acquires the inlet temperature from the inlet temperature sensor 136 and obtains the outlet temperature from the outlet temperature sensor 137. The auxiliary unit control section 13C controls the flow rate adjusting valve 135, respectively.

&Lt; 11th Embodiment >

Hereinafter, an eleventh embodiment of the present invention will be described with reference to the drawings.

33, the auxiliary unit 13 includes a gas side refrigerant pipe (a gas side internal pipe 131 detachably connected to the first refrigerant pipe 121, a liquid side refrigerant pipe A heating unit 13H for heating the refrigerant in the receiver 138, a receiver 138 for heating the refrigerant in the receiver 138, and a liquid-side internal piping 132 detachably connected to the receiver 138. The liquid- And a second connecting pipe 13h2 branched from the first connecting pipe 13h1 and connected to the gas-side internal pipe 131. The first connecting pipe 13h1 connects the liquid-side internal pipe 132 with the refrigerant, ).

The gas-side internal piping 131 is connected between the first refrigerant piping 121 and connects the evaporator 205 of the indoor unit 11 and the four-way valve 202 of the outdoor unit 10. The liquid-side internal piping 132 is connected between the second refrigerant pipeline 122 and connects the condenser 203 (the first expansion valve 204) of the outdoor unit 10 and the evaporator 205 of the indoor unit .

The receiver 138 is formed of a material having heat conductivity such as iron. Then, the receiver 138 is heated by the heating unit 13H. The heating section 13H is a heater provided on the outer surface of the receiver 138, for example. In addition, the receiver 138 is provided with a detecting unit for detecting the presence or absence of the liquid coolant inside. This detecting section has an upper temperature sensor 13T1 provided on the upper portion of the receiver 138 and a lower sensor 13T2 provided below the receiver 138. [ The subunit control unit 13C that has acquired the detection signals from the upper temperature sensor 13T1 and the lower temperature sensor 13T2 determines that there is no liquid refrigerant in the receiver 138 when the temperature difference becomes lower than the predetermined temperature do.

The first connecting pipe 13h1 is connected to the bottom surface located in the vertical lower portion of the receiver 138. [ That is, in the receiver 13h1 of the present embodiment, the refrigerant flows in and out of the first connecting pipe 13h1 provided in the vertical lower portion. Accordingly, the refrigerant in the receiver 138 flows out as a liquid unless it is almost gasified. The first connecting pipe 13h1 is provided with a liquid side opening / closing valve 139a which is a solenoid valve. The opening / closing of the liquid side on-off valve 139a is controlled by the sub-unit control section 13C.

The second connecting pipe 13h2 is provided with a flow rate adjusting valve (additional expansion valve) 13V for adjusting the amount of refrigerant flowing from the liquid pipe side to the gas pipe side through the second connecting pipe 13h2. The opening degree of the flow rate regulating valve 13V is controlled by the subsidiary unit control section 13C. On the downstream side of the flow rate adjusting valve 13V of the second connecting pipe 13h2, a gas side opening / closing valve 139b serving as a solenoid valve is provided. The gas side on-off valve 139b is controlled to be opened or closed by the sub-unit control section 13C. On the other hand, the switching mechanism 139 is constituted by the liquid side opening / closing valve 139a provided in the first connecting pipe 13h1 and the gas side opening / closing valve 139b provided in the second connecting pipe 13h2. On the other hand, the switching mechanism 139 may be constituted by a three-way valve provided at a connecting portion of the first connecting pipe 13h1 and the second connecting pipe 13h2.

Next, the cooling operation of the air conditioner 100 to which the auxiliary unit 13 is connected will be described briefly together with the function of the auxiliary unit control unit 13C.

(1) During normal cooling operation

34, in the normal cooling operation, the sub-unit control section 13C outputs an opening signal to the liquid side on-off valve 139a to bring the liquid side on-off valve 139a into an open state. The subunit control unit 13C outputs a closing signal to the flow regulating valve 13V and the gas side switching valve 139b to close the flow regulating valve 13V and the gas side switching valve 139b. Further, the sub-unit control section 13C turns off the heater 13H. A part of the liquid refrigerant flowing from the outdoor unit 10 side to the indoor unit 11 side is connected to the first connection pipe 13h1 by the air conditioner 100 performing the cooling operation, The amount of the refrigerant can be maintained.

(2) During the cooling operation at low ambient temperature

As shown in Fig. 35, in cooling operation at a low outside air temperature, the subunit control unit 13C outputs a closing signal to the liquid side on-off valve 139a to bring the liquid side on-off valve 139a into a closed state. Also, the sub-unit control section 13C turns on the heater 13H. The subunit control unit 13C outputs an opening signal to the flow regulating valve 13V and the gas side switching valve 139b to bring the flow regulating valve 13V and the gas side switching valve 139b into an open state. Thereby, the liquid refrigerant in the receiver 138 is supplied from the second connecting pipe 13h2 in the cycle. Accordingly, the refrigerant stored in the receiver 138 can be collected in the outdoor heat exchanger 203, thereby lowering the condensing ability of the outdoor heat exchanger 203.

Here, the sub-unit control section 13C controls the opening degree of the flow regulating valve 13V on the basis of the intake superheat degree of the outdoor unit 10 (the compressor 201). The subunit control unit 13C acquires the detection temperatures of the upper temperature sensor 13T1 and the lower temperature sensor 13T2 of the receiver 138. When the temperature difference between them reaches a predetermined temperature or lower, It is judged that the liquid refrigerant in the inside has been gasified and the liquid refrigerant has been supplied in the cycle. The auxiliary unit control section 13C turns off the heater 13H and outputs a closing signal to the flow rate adjusting valve 13V and the gas side switching valve 139b so that the flow rate adjusting valve 13V, And the gas side on-off valve 139b are closed.

(3) During heating operation

As shown in Fig. 36, in the heating operation, an open signal is outputted to the liquid side open / close valve 139a to bring the liquid side open / close valve 139a into an open state. The auxiliary unit control section 13C outputs a closing signal to the flow rate adjusting valve 13V and the gas side switching valve 139b to close the flow rate adjusting valve 13V and the gas side switching valve 139b. Further, the sub-unit control section 13C turns off the heater 13H. In this state, a part of the liquid refrigerant flowing from the indoor unit 11 side to the outdoor unit 10 side through the liquid-side internal piping 132 is discharged to the first connecting pipe 13h1 by the air conditioner 100 performing the cooling operation, The amount of the refrigerant can be maintained.

According to the auxiliary unit 13 of this embodiment configured as described above, the refrigerant stored in the receiver 138 at the time of the cooling / heating operation is heated by the heater 13H at the time of the cooling operation at the low outside air temperature, Side heat exchanger 203 can be collected at the time of the cooling operation at the low outside air temperature and the liquid refrigerant can be collected in the outdoor side heat exchanger 203 by the condensation of the outdoor heat exchanger 203 Performance can be lowered. Accordingly, it is possible to adjust the heat exchange amount of the outdoor heat exchanger (203) and the heat exchange amount of the indoor heat exchanger (205) at the time of the cooling operation at the low outdoor air temperature, Can be performed. In addition, the function of the auxiliary unit 13 can be externally attached to the existing air conditioner 100, so that the function can be given to the existing air conditioner 100.

On the other hand, in the tenth embodiment and the eleventh embodiment, the air conditioner having one outdoor unit and one indoor unit has been described as an example, but two or more indoor units may be connected in parallel for example, For example, in parallel.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific structure is not limited to the above, and various design modifications can be made within the scope of the present invention. The constituent elements of the above-described embodiments may be combined.

100: air conditioner 10: outdoor unit
10F: outdoor fan 11: indoor unit
11F: indoor fan 20: refrigerant circuit
30: air conditioner control unit 40: refrigerant amount detection device
201: compressor 203: condenser (outdoor heat exchanger)
204: first expansion valve 205: evaporator (outdoor heat exchanger)
208: outlet temperature sensor (first temperature sensor) 209: liquid pipe temperature sensor (second temperature sensor)
213: Subcooler 214: Bypass
215: second expansion valve 411:
412: Refrigerant state acquisition unit 413: Refrigerant amount calculation unit

Claims (19)

A refrigerant circuit comprising a compressor, a condenser, an expansion valve and an evaporator;
Wherein the control unit determines the supercooled state or the gas-liquid two-phase state at the outlet of the condenser and determines the amount of refrigerant in the refrigerant circuit based on at least one of the temperature and the pressure detected in the refrigerant circuit, A refrigerant amount detecting device for calculating a ratio; And
And a controller for controlling the refrigerant circuit according to a refrigerant amount ratio calculated by the refrigerant amount detecting device. The method according to claim 1,
The refrigerant amount detection device includes:
And calculates an average value of the refrigerant amount ratios based on the calculated refrigerant amount ratios. 4. The method according to any one of claims 1 to 3,
The refrigerant circuit includes:
A first temperature sensor for detecting a first refrigerant temperature at an outlet of the condenser; And
And a second temperature sensor for detecting the second refrigerant temperature on the downstream side of the fluid resistance provided on the outlet side of the condenser,
Wherein the refrigerant amount detection device determines a supercooled state or a gas-liquid two-phase state based on the first refrigerant temperature and the second refrigerant temperature. 4. The method according to any one of claims 1 to 3,
The refrigerant circuit includes:
And a subcooler located between the condenser and the expansion valve, for cooling the liquid refrigerant generated in the condenser. 5. The method of claim 4,
Wherein,
And controls at least one of the compressor, the condenser, the expansion valve, the evaporator, and the subcooler to operate constantly under the control of the refrigerant amount detecting device. 6. The method of claim 5,
The refrigerant circuit includes:
A refrigerant storage container for storing charged refrigerant; And a refrigerant injection valve for controlling the refrigerant supplied from the refrigerant storage container,
Wherein the control unit controls the refrigerant injection valve when the average value of the refrigerant amount ratios reaches 100% when the refrigerant is charged. The method according to claim 1,
The refrigerant circuit includes:
A receiver for storing surplus refrigerant present in the refrigerant circuit in a supercooled liquid state; And
And a flow rate adjuster for reducing the pressure of the refrigerant flowing out of the receiver and adjusting the flow rate of the refrigerant. The method according to claim 6,
Wherein the refrigerant comprises a non-azeotropic mixed refrigerant comprising R32 and HFO1234yf or HFO1234ze. 9. The method of claim 8,
Wherein the non-azeotropic mixed refrigerant has a content of HFC of less than 70 wt%, a content of HFO 1234yf or HFO 1234ze of less than 30 wt%, and the balance of natural refrigerant. The method according to any one of claims 7 to 9,
The volume of the receiver,
Wherein the amount of refrigerant obtained by subtracting the amount of refrigerant during the cooling operation from the amount of refrigerant during the heating operation of the refrigerant circuit is equal to the volume converted into the supercooled liquid state. The method according to any one of claims 7 to 9,
The refrigerant circuit includes:
And a supercooler condensed in the evaporator or the condenser and a supercooler for supercooling the main refrigerant by heat exchange between the refrigerant classified in the main refrigerant and the decompressed refrigerant decompressed by the supercooling pressure reducing valve. 12. The method of claim 11,
And the receiver further comprises at least one refrigerant amount detection mechanism for detecting an amount of refrigerant in the receiver. The method according to claim 1,
And an auxiliary unit connected to the indoor unit including the compressor and the condenser and the indoor unit including the evaporator, wherein the auxiliary unit is detachable from the piping of the refrigerant circuit, and includes the refrigerant amount detection device. 14. The method of claim 13,
The sub-
And a refrigerant injection valve for adjusting the refrigerant piping of the auxiliary unit when the calculated refrigerant amount ratio reaches 100% when the refrigerant circuit is charged into the refrigerant circuit. 15. The method according to any one of claims 13 to 14,
The sub-
A refrigerant storage container for storing charged refrigerant; And a refrigerant injection valve for controlling the refrigerant supplied from the refrigerant storage container,
Wherein the control unit controls the refrigerant injection valve when the average value of the refrigerant amount ratios reaches 100% when the refrigerant is charged. 16. The method of claim 15,
The sub-
And an auxiliary heat exchanger for performing heat exchange with the external heat source device except for the air conditioner. 17. The method of claim 16,
The sub-
A receiver for storing surplus refrigerant present in the piping of the auxiliary unit in a supercooled liquid state; And
And a flow rate adjuster for reducing the pressure of the refrigerant flowing out of the receiver and adjusting the flow rate of the refrigerant. A control method for an air conditioner including a refrigerant circuit including a compressor, a condenser, an expansion valve, and an evaporator,
Determining whether the refrigerant state at the outlet of the condenser is a supercooled state or a gas-liquid two state;
Calculating a refrigerant amount ratio in the refrigerant circuit based on at least one of a temperature and a pressure detected in the refrigerant circuit and a predetermined value according to the refrigerant state;
And controlling the refrigerant circuit according to the calculated refrigerant amount ratio. 19. The method of claim 18,
And calculating an average value of the refrigerant amount ratios based on the calculated refrigerant amount ratios.

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