JPH09113043A - Electric apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attempt to optimize the operating capacity of a refrigerant circuit even when the composition ratio of mixed refrigerant is varied. SOLUTION: The electric apparatus is operated to circulate the mixed refrigerant containing a plurality of refrigerants having different characteristics and mixed in a refrigerant circuit. In the apparatus, the mixing ratio in the mixed refrigerant is detected. Correcting means 79 corrects the output from a pressure reducing amount control unit 62 based on the detected ratio, and controls the pressure reducing amount of the pressure reducing unit. When circulating in the circuit, the reducing unit is controlled in response to not only the operating based based on a compressor but also to the mixed ratio of the refrigerant, and hence the operating capacity of the circuit can be optimized.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a compressor, a condenser,
The present invention relates to an electric device such as a refrigerator and an air conditioner having a refrigerant circuit having a pressure reducing device and an evaporator, and particularly to an electric device using a mixed refrigerant in which a plurality of refrigerants having different characteristics are mixed.

[0002]

2. Description of the Related Art For example, a refrigerant circuit of an air conditioner as an electric device has a compressor, a condenser, a pressure reducing device, and an evaporator, and a compressor compresses and discharges a gas refrigerant to circulate it in the refrigerant circuit. ing.

On the other hand, as the refrigerant filled in the refrigerant circuit,
Conventionally, R-12 and R-50 having a chlorine group were used,
Due to the potential for depletion of the ozone layer above the ground, R-22 (chlorodifluoromethane), which has a low content of chlorine groups, and R-32, which does not contain chlorine groups, are included for the purpose of environmental protection.
(Difluoromethane), R-125 (pentafluoroethane), R-134a (tetrafluoroethane) or a mixture thereof (hereinafter referred to as "HFC-based refrigerant") is used as an alternative refrigerant.

Of these refrigerants, a mixed refrigerant is often used in order to exhibit the characteristics of the refrigerant used in the air conditioner.

[0005]

However, in the refrigerant circuit of the air conditioner, the refrigerant pipes are connected by welding or the like, and if used for many years, the connection parts of the respective refrigeration equipment such as the refrigerant pipes and pressure reducers. There is a risk that the refrigerant may leak from.

[0006] When such a refrigerant leak occurs, if the air conditioner is operated as it is, the capacity of the air conditioner will decrease.

On the other hand, it is conceivable to replenish the refrigerant, but in the case of using a single refrigerant such as R-22 which has been conventionally used, the refrigerant is replenished by the leaked refrigerant amount. However, when mixed refrigerants having different characteristics are used, it is almost unlikely that the refrigerant components leak evenly, so that the composition ratio of the refrigerant components changes. It is difficult to return the composition ratio of the refrigerant components to the initial composition ratio even if the initially filled refrigerant is replenished to the mixed refrigerant having such a changed refrigerant composition as it is.

If the composition ratio of the mixed refrigerant changes and remains different from the initially set value, the operating capacity of the air conditioner cannot be optimized.

The present invention has been made to solve the above problems, and provides an electric device capable of optimizing the operating capacity of an air conditioner even when the composition ratio of a mixed refrigerant changes. To do.

[0010]

According to a first aspect of the present invention, there is provided a refrigerant circuit including a compressor, a condenser, a pressure reducing device, and an evaporator, which is a mixed refrigerant obtained by mixing at least two kinds of refrigerants having different characteristics. In the electrical equipment configured to circulate in the above, in an electric device configured to change the capacity of the compressor according to the load, the decompression amount of the decompression device based on the operating state of the refrigerant circuit due to the operation of the compressor. A decompression amount control unit that generates an output for setting, a mechanism that adjusts the decompression device so as to obtain a decompression amount that is set in response to this output, and a mixture of the mixed refrigerant that circulates in the refrigerant circuit. A correction means for correcting the output from the decompression amount control unit based on the ratio is provided.

According to the first aspect of the invention, the decompression amount control unit sets the decompression amount of the decompression device based on the operating state of the refrigerant circuit due to the operation of the compressor, and further, the decompression amount of the mixed refrigerant in the refrigerant circuit is set. If the mixture ratio is detected and the detected value changes, the characteristics of the refrigerant circulating in the refrigerant circuit change, and it is optimal to set the opening of the pressure reducing device in response to only the output of the compressor. Not suitable to get. Therefore, when the mixing ratio of the mixed refrigerant changes, the output from the pressure reduction amount control unit is corrected based on the changed mixing ratio, and the decompression device is opened in consideration of the mixing ratio of the mixed refrigerant. Control the degree. This makes it possible to optimize the operating capacity of the refrigerant circuit.

According to a second aspect of the present invention, in the first aspect of the invention, the correction means functions when the mixing ratio of the mixed refrigerant exceeds a predetermined range.

According to the second aspect of the present invention, the correction means does not function when the mixing ratio of the mixed refrigerant changes, but functions when the mixing ratio exceeds a predetermined range. Stable operation can be achieved.

According to a third aspect of the present invention, in the second aspect of the present invention, the mixing ratio of the mixed refrigerant is a mixing ratio of a specific refrigerant in the mixed refrigerant circulating in the refrigerant circuit, According to the invention of claim 3, the correcting means functions in a direction in which the decompression amount of the decompression device decreases in accordance with the increase of the mixing ratio. The detection of the mixing ratio facilitates the detection of the mixing ratio by measuring the mixing ratio of the specific refrigerant in the mixed refrigerant. Further, when the mixing ratio of the specific refrigerant increases, the capacity of the refrigerant decreases, so the decompression amount of the decompression device is decreased and the refrigerant circulation amount is controlled to increase.

According to a fourth aspect of the present invention, the correction means functions after a lapse of a predetermined time from the start of operation of the compressor.

According to the invention described in claim 4, since the mixed refrigerant circulating in the refrigerant circuit is not sufficiently stable before a predetermined time has passed from the operation of the air conditioner, a predetermined time when the operation is stable has elapsed. After that, the mixture ratio of the refrigerant is detected, and the opening degree of the decompression device is controlled according to the mixture ratio of the refrigerant to enhance the capacity of the air conditioner.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing a general household air conditioner. This type of air conditioner is composed of a use side unit A arranged indoors and a heat source side unit B arranged outdoors, both of which are connected by a refrigerant pipe 300.

FIG. 2 is a refrigerant circuit diagram showing a refrigeration cycle of the air conditioner shown in FIG.

Reference numeral 1 denotes a compressor, which is composed of a motor section whose rotational speed is controlled at a variable speed by an inverter, and a compression section driven by this motor section. 2 is a muffler,
Vibration and noise due to pulsation during discharge of the refrigerant discharged from the compressor 1 are suppressed. A four-way switching valve 3 is for switching the flow of the refrigerant during the cooling / heating operation. Reference numeral 4 is a heat source side heat exchanger, and 5 is an electric expansion valve, which functions as a pressure reducing device. 6 is a screen filter, 7 is a heat exchanger on the use side, 8 is a muffler similar to the above-mentioned muffler, 9 is an accumulator, and 10 is an electromagnetic on-off valve, which are annularly connected by a refrigerant pipe as shown in FIG. .

The refrigerant discharged from the compressor 1 is shown by a solid line arrow (cooling operation), a dotted line arrow (heating operation), and a solid line in accordance with the switching position of the four-way switching valve 3 and the opening / closing of the electromagnetic opening / closing valve 10. Like the dotted arrow (defrosting operation), the flow direction is determined according to the three modes. During cooling operation,
The refrigerant discharged from the compressor 1 includes a compressor 1, a muffler 2, a four-way switching valve 3, a heat source side heat exchanger 4, an electric expansion valve 5,
The screen filter 6, the use side heat exchanger 7, the muffler 8, the four-way switching valve 3, the accumulator 9, and the compressor 1 are circulated in this order, the heat source side heat exchanger 4 is a condenser, and the use side heat exchanger 7 is an evaporator. And the cooling operation by the use side heat exchanger 7 becomes possible. During the heating operation, the refrigerant discharged from the compressor 1 is the compressor 1, the muffler 2, the four-way switching valve 3, the muffler 8, the use side heat exchanger 7, the screen filter 6, the electric expansion valve 5, the heat source side heat exchanger. 4, the four-way switching valve 3, the accumulator 9, and the compressor 1 are circulated in this order, the heat source side heat exchanger 4 functions as an evaporator, the use side heat exchanger 7 functions as a condenser, and heating by the use side heat exchanger 7 is performed. It becomes possible to drive. During the defrosting operation (when the refrigerant is circulating as in the heating operation), the electromagnetic opening / closing valve 10 is opened, and a part of the high-temperature refrigerant discharged from the compressor 1 is transferred to the heat source side heat exchanger 4. Is directly supplied to the heat source side heat exchanger 4 in order to raise the temperature of the heat source. As a result, the temperature of the heat source side heat exchanger 4 rises, frost is less likely to form, and some defrosting is performed. When the defrosting operation does not function sufficiently (when the outside air temperature is particularly low), reverse cycle defrosting (the refrigerant circulates as in the cooling operation) is forcibly performed.

The diameter of the refrigerant pipe provided with the electromagnetic opening / closing valve 10 is smaller than that of the normal refrigerant pipe, and the amount of refrigerant flowing is adjusted. An adjustment mechanism may be provided.

The compression capacity of the compressor 1 is variable by controlling the rotation speed of its motor section. The rotation speed is controlled in response to a control signal from the microcomputer 41 described later.

The electric expansion valve 5 is an expansion valve that controls the opening degree in stages to adjust the amount of pressure reduction during the refrigeration cycle. In the present embodiment, the step motor 51 has a large number of spindles. The opening of the step motor 51 is controlled in steps, and the step motor 51 receives a command from the microcomputer 41 to change its rotation angle to 48 degrees, for example.
It is digitally controlled in multiple stages such as 0 stage or 256 stages.

In the present embodiment, either a non-azeotropic mixed refrigerant or a mixed refrigerant which is an azeotropic mixed refrigerant can be used, but in this embodiment, an azeotropic mixed refrigerant is used as an example for description. To do.

As the azeotropic mixed refrigerant (pseudo-azeotropic refrigerant),
For example, R-410A or R-410B is used. For example, R-410A is a two-component mixed refrigerant,
R-32 as a refrigerant is 50 wt% and R-125 as a second refrigerant is 50 wt%. The mixed refrigerant has a boiling point of -52.2 ° C and a dew point of -52.2 ° C. Also, R
-410B is the first refrigerant R-32 45Wt%,
The second refrigerant R-125 has a composition of 55 wt%,
It shows almost the same characteristics as R-410A.

When azeotropic mixed refrigerants such as R-410A and R-410B are used, the boiling point of the refrigerant of each component (the boiling point of R-32 is -51.7 ° C, the boiling point of R-125 is Since the temperature is close to −48.5 ° C., a rapid change in the refrigerant composition is unlikely to occur during evaporation, and there is no need to consider a problem such as temperature glide caused by the change in the refrigerant composition. Therefore, control during driving becomes easy. However, the condensing pressure tends to be high, and refrigerant leakage from the high pressure side of the refrigerant circuit is likely to occur. Since the boiling points of the respective refrigerant components are different from each other, the respective components of the mixed refrigerant do not always leak uniformly, and the composition ratio of the mixed refrigerant may change.

R-407c can also be used as the mixed refrigerant. This R-407c is a three-component mixed refrigerant, which contains 23 wt% of R-32 as the first refrigerant,
The second refrigerant R-125 is 25 wt% and the third refrigerant R-134a is 52 wt%. The mixed refrigerant has a boiling point of -43.9 ° C and a dew point of -36.5 ° C.
The R-407c having such characteristics can be applied similarly to the above-described two-component mixed refrigerant. 2
The invention is not limited to the component system and the three-component system, and is similarly applied to a four-component or five-component mixed refrigerant.

Moreover, in the refrigerant circuit, the opening degree (amount of pressure reduction) of the electric expansion valve is adjusted based on the composition ratio in the mixed refrigerant so that the operating capacity is optimally maintained during the operation of the air conditioner.
Therefore, when the composition ratio of the mixed refrigerant changes, the operating state of the air conditioner cannot be optimally maintained.

Therefore, in the present embodiment, even if the composition ratio of the mixed refrigerant changes, the opening degree of the electric expansion valve 5 is adjusted to maintain the optimum operation.

FIG. 3 is a control circuit diagram of the air conditioner.
The left side shows the control circuit of the utilization side unit A, and the right side shows the control circuit of the heat source side unit B with the dashed line in the center of FIG. 3 as the boundary. Both control circuits have power line 10
0 and the control line 200.

The user side unit A includes a rectifying circuit 11 and
A power supply circuit 12 for the motor, a power supply circuit 13 for the control, a motor drive circuit 15, a switch board 17,
The receiving circuit 18a, the display board 18, and the flap motor 1
9 and 9 are provided.

The rectifier circuit 11 rectifies 100V AC power supplied via the plug 10a and supplies DC power to the respective power supply circuits 12 and 13. The motor power supply circuit 12 adjusts the DC voltage supplied to the DC fan motor 16 to a voltage of 10 to 36V. This power supply circuit 1
Reference numeral 2 is a heat exchanger on the use side by a fan driven by the DC fan motor 16 by changing the rotation speed of the DC fan motor 16 by varying the DC voltage in the range of 10 to 36 V according to the signal sent from the microcomputer 14. This is for controlling the amount of conditioned air conditioned in 7 to be blown into the conditioned room.

The control power supply circuit 13 generates a 5V DC voltage supplied to the microcomputer 14. The motor drive circuit 15 responds to a signal from the microcomputer 14 based on the rotational position information of the DC fan motor 16 to control the timing of switching the energization to the stator winding of the DC fan motor 16. Switch board 17
Is fixed to the operation panel of the use side unit A, and the switch board 17 is provided with an on / off switch, a trial run switch, and the like. The state of these switches is captured by the microcomputer 14 by key scanning.
The receiving circuit 18a is the wireless remote controller 6
The remote control signal from 0 (for example, ON / OFF signal, cooling / heating switching signal, room temperature setting signal, etc.) is received, demodulated, and transferred to the microcomputer 14.
The display board 18 dynamically lights an LED based on a signal from the microcomputer 14 to display an operating state of the air conditioner. The flap motor 19 functions to move the flap that is conditioned in the utilization side heat exchanger 7 and changes the blowing direction of the conditioned air blown by the fan.

Further, in this control circuit, a room temperature sensor 20 for measuring the room temperature, a heat exchanger temperature sensor 21 for measuring the temperature of the utilization side heat exchanger 7, and a room humidity are measured. Humidity sensor 22 of The measured values detected by these sensors are A / D converted by the microcomputer 14 and taken in. The microcomputer 14 calculates based on these input information (acquisition information), and outputs a signal for determining the operating capacity of the four-way switching valve and the compressor 1 through the serial circuit 23 and the terminal board T ₃ to the heat source side unit B. Send to. Also, Triac 26
The heater relay 27 and the heater relay 27 are controlled by the microcomputer 14 through the driver 24. Thereby, the electric power supplied to the reheating heater 25 used in the dehumidifying operation (state of the refrigerating cycle used during the cooling operation) is controlled stepwise.

Reference numeral 30 is an external ROM that stores specific data indicating the type and characteristics of the air conditioner. These specific data are taken out from the external ROM immediately after the plug 14a is connected to the outlet and power is supplied to start up the microcomputer 14. The microcomputer 14 does not input a command from the wireless remote controller 60 or detect the state of an ON / OFF switch or a trial run switch (operation will be described later) until the specific data is taken out from the external ROM 30.

Next, the control circuit of the heat source side unit B will be described.

In the heat source side unit B, the terminal board T
_{'1, T'2, T'3} are connected to each use-side unit terminal plate T ₁ arranged in A, T _2, T _3.
Reference numeral 31 is a varistor connected in parallel to the terminal plates T ′ ₁ and T ′ ₂ , 32 is a noise filter, 34 is a reactor, 35 is a voltage doubler rectifier circuit, and 36 is a noise filter.

Reference numeral 39 is a serial circuit for dispersing the control signal supplied from the user side unit A from the power line through the terminal board T'3, and the dispersed signal is transmitted to the microcomputer 41. Reference numeral 40 is a current detector, which detects the current supplied to the heat source side unit B by current transformation (CT) and converts it into a signal for the microcomputer 41. 42 is a constant voltage circuit for generating electric power for operating the microcomputer 41, 38 is a three-phase inverter circuit, which controls the electric power supplied to the compressor 1 based on a control signal from the microcomputer 41, and compresses it. Adjust the driving ability of Aircraft 1. Three-phase inverter circuit 38
Connects six power transistors in the form of a three-phase bridge. Reference numeral 43 is a motor unit for operating the compressor 1 of the refrigeration cycle, and 44 is a discharge side temperature sensor for detecting the temperature of the refrigerant discharged from the compressor 1.
45 is a fan motor, the speed of which is controlled in three stages,
The heat source side heat exchanger is arranged so that air can be sent to it. The four-way switching valve 3 and the solenoid valve 10 switch the refrigerant passages of the refrigeration cycle as described above. Further, in the heat source side unit B, an outdoor temperature sensor 48 for detecting the outdoor temperature is mounted near the air intake of the fan motor 45, and a heat exchanger temperature sensor 49 for detecting the temperature of the heat source side heat exchanger is provided on the heat source side. Installed in heat exchanger. The detection values obtained by these temperature sensors 48 and 49 are A / D converted by the microcomputer 41 and taken in.

Reference numeral 50 is an external ROM of the user side unit A.
It is an external ROM having the same function as 30. The specific data of the heat source side unit B is the same as that described for the external ROM 30, but is stored in the ROM 50.

The symbol F in each control circuit of the heat source side unit B and the use side unit A is a fuse.

Each of the microcomputers (control devices) 14 and 41 is a ROM that stores a program in advance,
A RAM that stores reference data and a CPU that calculates a program are stored in the same container (87C196MC (MC sold by Intel Corporation).
S-96 series) and the like can be used).

On the other hand, in the present embodiment, the microcomputer 41 controls the valve opening degree of the electric expansion valve as the pressure reducing device 5 in response to the operating capacities of the mixing ratio detector 53 and the compressor 1. An opening signal is sent to the step motor 51 that drives the throttle valve of the electric expansion valve 5.

The opening of the electric expansion valve 5 is usually controlled based on the evaporation temperature of the refrigerant so that the evaporation temperature of the refrigerant in the refrigeration cycle is constant, regardless of the operating capacity of the compressor. Since feedback control of the evaporation temperature causes a time delay, when the operating capacity of the compressor fluctuates, the opening control of the electric expansion valve 5 also delays. Such control may be used when the time delay is not a problem.

In the present embodiment, the opening degree of the electric expansion valve 5 does not cause a time delay based on the experimental result expressed by a unique arithmetic expression for each refrigerant circuit with respect to the operating capacity of the compressor 1. Basic control is performed.

Further, the microcomputer 41 is connected to a mixing ratio detector 53 for detecting the mixing ratio of the mixed refrigerant (R-410A will be described as an example) in the refrigerant circuit, and the mixing ratio detector 53 outputs the mixed ratio. Upon receiving the detection signal, the opening degree of the electric expansion valve is corrected based on the detection signal in addition to the basic control so that the operation can be performed at the optimum pressure reduction amount in response to the change in the mixing ratio of the refrigerant. There is. The mixing ratio detector 53 (also referred to as a mixing ratio detecting means or a refrigerant concentration detector) is a ratio of the first refrigerant R-32 or the second refrigerant R-125 refrigerant in the mixed refrigerant to the mixed refrigerant. This ratio, that is, the mixing ratio is a refrigerant pressure in the refrigerant circuit, by measuring the refrigerant temperature, etc., from the graph previously obtained the relationship between the composition ratio of the mixed refrigerant and the refrigerant pressure or the refrigerant temperature. Desired.

In this embodiment, the refrigerant mixture ratio detector 5 is used.
3 is a sonic velocity measuring device 55a, 55b for measuring the sonic velocity in a liquid state in the refrigerant circuit in the mixed refrigerant, thermometers 55c, 55d for measuring the temperature of the mixed refrigerant, and a pressure gauge for measuring the pressure of the mixed refrigerant. Equipped with 55e and 55f, the refrigerant concentration is surely measured. The method for measuring the mixing ratio of the mixed refrigerant is not limited to this, and it may be obtained from changes in the physical properties such as the specific gravity of the refrigerant and the evaporation temperature.

The mixing ratio detector 53 has a microcomputer 5 programmed with relational data of sound velocity, temperature and pressure.
7 is built in, and when the measured values of the sonic velocity, temperature, and pressure of the mixed refrigerant are input, arithmetic processing is performed, and the concentration (composition ratio) of the mixed refrigerant is displayed on the display device 58 and supplied to the microcomputer 41. . Incidentally, the microcomputer 57
The function of may be included in the microcomputer 41.

An opening adjusting means 61 (described later) for correcting the opening of the electric expansion valve 5 in addition to the basic control is built in the microcomputer 41, and the mixing ratio of the first refrigerant is the original. When it is larger than the set value, the opening of the expansion valve of the electric expansion valve 5 is adjusted according to the large value, and the refrigerant circulation amount is increased or decreased based on the mixture ratio to adjust the air conditioner. It has the best ability.

The opening degree adjusting mechanism (opening degree adjusting means) 61 of the electric expansion valve 5 (which is configured by executing a program in the microcomputer 41) will be described below.

The step motor 51 of the electric expansion valve 5 is controlled by a signal from the expansion valve opening controller 62, as shown in FIG. The drive of the expansion valve opening control unit 62 is controlled on the basis of the operating capacity of the compressor.
The expansion valve opening control unit 62 issues an opening signal KS according to the operating capacity of the compressor, and the step motor control unit 64 controls the opening of the electric expansion valve 5 to be the opening indicated by the opening signal KS. Then, the step motor 51 is driven. Step motor 51
Has 0 to 480 control steps or 0 to 250 control steps in the present embodiment.

The mixing ratio detector 53 is connected to a processing unit 79. In the processing unit 79, the expansion valve opening degree control unit 62 is based on the mixing ratio of each refrigerant of the mixed refrigerant obtained by the mixing ratio detecting means 53. The opening signal of the electric expansion valve 5 is adjusted by adding a correction to the opening signal KS issued from the.

The mixing ratio detector 53 outputs a mixing ratio detection signal DS to the processing section 79. The mixing ratio detector 53 is a first refrigerant of the mixed refrigerant R-410A, difluoromethane (R). -32) and the mixture ratio of pentafluoroethane (R-125) as the second refrigerant are detected. First
The refrigerant difluoromethane (R-32) is represented by the symbol α, and the second refrigerant pentafluoroethane (R-12) is used.
When 5) is represented by the symbol β, the concentration (mixing ratio) of difluoromethane (R-32) of R-410A is α / (α + β).

In the processing section 79, with respect to the mixture ratio of the refrigerant,
A calculation process is performed to determine a correction coefficient for the opening signal KS as to how much the opening signal KS issued from the expansion valve opening control unit 62 should be corrected to obtain the most optimal operation. The calculation process for obtaining the correction coefficient may be to obtain the correction coefficient in correspondence with a graph previously obtained from an experiment as shown in FIG. In FIG. 4, the horizontal axis shows the first
The concentration (mixing ratio) of the refrigerant α is taken and the vertical axis is the correction coefficient, and the correction value of the opening signal KS with respect to the concentration of the first refrigerant α is obtained.

The processing unit 79 does not accept the detection signal from the mixing ratio detector 53 for a predetermined time until the state of the refrigerant circulating in the refrigerant circuit becomes stable. After the acceptance is started, the detection signal is detected at every predetermined time. It is designed to accept and process signals.

The processing unit 79 is, for example, 30 times at predetermined time intervals.
The command signal IS based on the correction coefficient is calculated once a second and is given to the opening signal KS. Step motor 5
1 is operated by a necessary number of steps by the opening signal KS after the correction coefficient is given, thereby adjusting the opening of the expansion valve 5. In the present embodiment, the concentration (mixing ratio) α /
When the value of (α + β) difluoromethane (R-32) α becomes large and the mixing ratio of difluoromethane (R-32) α and pentafluoroethane (R-125) β is not 1: 1, The expansion valve 5 is opened by increasing the opening degree of the expansion valve 5.

Next, the operation of the above-described embodiment of the present invention will be described with reference to the flowchart of FIG.

First, when the operation of the air conditioner is started, during the cooling operation, as shown by the solid arrow in FIG.
The refrigerant discharged from the muffler 2, the four-way switching valve 3, the heat source side heat exchanger (outdoor heat exchanger) 4, the electric expansion valve 5, the screen filter 6, the use side heat exchanger (indoor heat exchanger)
7, the muffler 8, the four-way switching valve 3, and the accumulator 9 circulate through the refrigerant circuit in this order, the use-side heat exchanger 7 functions as an evaporator, and the electric expansion valve 5 reduces the pressure. During the heating operation, the refrigerant discharged from the compressor 1 is a muffler 2, a four-way switching valve 3, a muffler 8, a use side heat exchanger (indoor heat exchanger) 7, a screen filter 6, an electric motor as shown by a dashed arrow. Expansion valve 5, heat source side heat exchanger (outdoor heat exchanger)
4, the four-way switching valve 3, and the accumulator 9 circulate in the refrigerant circuit in this order, and the heat source side heat exchanger 4 functions as an evaporator,
The pressure is reduced by the electric expansion valve 5.

Next, the opening control of the electric expansion valve 5 will be described.

Although the opening of the electric expansion valve 5 is determined in consideration of the characteristics of the mixed refrigerant used, the opening degree of the electric expansion valve 5 is largely dependent on the amount of the refrigerant circulating in the refrigerant circuit in order to meet the required load, and the compression is performed. The opening is controlled by the operation output of the machine. That is, when the operation output of the compressor becomes high, the electric expansion valve 5
The opening signal KS is issued from the expansion valve opening control unit 62 to the step motor 51 so as to open.

Further, the opening adjustment mechanism 61 corrects the opening signal KS of the electric expansion valve as shown in FIG. 6 in response to the change in the refrigerant mixture ratio.

After the operation of the air conditioner is started, it is determined in step S1 whether or not a predetermined time has elapsed since the operation of the compressor 1. The predetermined time is a time for stabilizing the state of the refrigerant circulating in the refrigerant circuit, and the predetermined time is preferably 2 to 5 minutes, and in the present embodiment, for example, 3 minutes. If the predetermined time has not elapsed, step S1 is performed again.
Is returned to.

When the predetermined time has elapsed, the routine proceeds to step S2, where the mixing ratio detector 53 detects the mixing ratio α / (α + β) of the first refrigerant α in the mixed refrigerant. The mixing ratio detector 53 issues a detection signal DS to the microcomputer 41, and proceeds to step S3.

At step S3, in the processing section 79,
A calculation process for determining a correction value for the opening signal KS that determines the opening of the electric expansion valve 5 based on the operating capacity of the compressor is performed to obtain a correction coefficient for the opening signal KS.
Referring to FIG. 4, the mixing ratio of the first refrigerant α is a set value, and in the present embodiment, the mixing ratio is 1: 1. Therefore, when the setting value of the first refrigerant α is 0.5, the mixing ratio is the set value. If the mixing ratio is 0.5, the correction coefficient is 1 because the mixing ratio remains at the initially set value, and when the mixing ratio of the first refrigerant α is larger than 0.5, the correction coefficient is larger than 1 and The correction coefficient becomes smaller than 1 when the mixture ratio of the refrigerant α becomes smaller than 0.5.
It should be noted that the range where the mixing ratio is 0.5 ± α is set as a range where the insensitive body is not corrected (correction coefficient is 1). The value of α is about 0.1.

In step S4, the opening coefficient is corrected by multiplying the opening signal KS by the correction coefficient obtained in step S3. In this case, if the correction coefficient is greater than 1,
The step motor 5 is adjusted so that the opening degree of the expansion valve 5 is increased.
The opening signal for driving 1 is corrected. That is, when the mixing ratio of the first refrigerant α becomes larger than 0.5, the opening degree of the electric expansion valve 5 becomes large.

In step S5, the step motor 5 is operated based on the opening signal corrected by the correction coefficient as described above.
1 is driven.

In step S6, it is determined whether or not a predetermined time, 30 seconds in this embodiment, has elapsed. If the predetermined time has elapsed, the process returns to step S1.

As described above, the opening degree of the electric expansion valve 5 is finely controlled in consideration of the change of the mixture ratio of the refrigerant so that the opening degree of the electric expansion valve 5 is finely controlled so as to always obtain the optimum operation.
Even when the composition ratio of the mixed refrigerant changes, the operating capacity of the air conditioner can be optimized.

The present invention is not limited to the above embodiment,
Various modifications can be made without departing from the scope of the claims.

For example, in the above-described example, the processing unit 79 shown in FIG. 5 detects the mixing ratio of the first refrigerant α (R-32), and when the mixing ratio of the first refrigerant to the entire mixed refrigerant is large. Was controlled to open the opening degree of the electric expansion valve 5, but the mixing ratio of the second refrigerant β (R-125) was detected, and the mixing ratio of the second refrigerant β (R-125) to the entire mixed refrigerant was When the amount is small, the same effect can be obtained by controlling the opening of the electric expansion valve 5 to open.

[0071]

According to the first aspect of the present invention, in the electric device configured to change the capacity of the compressor according to the load, the decompression amount control unit controls the operation state of the refrigerant circuit by the operation of the compressor. Generate an output for setting the decompression amount of the decompression device based on, while adjusting the decompression device so as to obtain the decompression amount set in response to this output, the correction means to the mixing ratio of the mixed refrigerant. Since the output from the decompression amount control unit is corrected based on this, the opening of the decompression device is controlled in consideration of the mixing ratio of the mixed refrigerant. Therefore, it is possible to increase the capacity of the refrigerant circuit by increasing / decreasing the refrigerant circulation amount and optimize the operating capacity.

According to the invention of claim 2, claim 1
In addition to the invention described in (1), when the correction means exceeds a predetermined range, the correction means is caused to function, whereby stable operation can be achieved.

According to the invention described in claim 3, according to claim 2
In the invention described in (1), the mixing ratio can be easily detected by measuring the mixing ratio of the specific refrigerant of the mixed refrigerant. Further, when the mixing ratio of the specific refrigerant increases, the capacity of the refrigerant decreases, so that the decompression amount of the decompression device can be decreased and the refrigerant circulation amount can be increased.

According to the invention described in claim 4, since the mixed refrigerant circulating in the refrigerant circuit is not sufficiently stable before the predetermined time has passed from the operation, the mixture ratio of the refrigerant is passed after the predetermined time when the operation is stable. Can be detected and the opening degree of the decompression device can be controlled according to the mixture ratio of the refrigerants to enhance the capacity of the refrigerant circuit.

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a diagram showing a refrigerant circuit of the air conditioner shown in FIG.

FIG. 3 is a control circuit diagram of the refrigerant circuit of FIG.

FIG. 4 is a diagram showing a relationship between a concentration (mixing ratio) stored in a processing unit and a correction coefficient.

FIG. 5 is a block diagram showing a configuration of a mechanism for adjusting the opening degree of an expansion valve.

FIG. 6 is a flowchart showing a process of controlling the opening degree of the electric expansion valve based on a change in the composition ratio of the mixed refrigerant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 4 Heat source side heat exchanger (condenser during cooling operation) 5 Electric expansion valve (pressure reducing device) 7 Utilization side heat exchanger (evaporator during cooling operation) 53 Mixing ratio detector (mixing ratio detecting means) 62 Expansion Valve opening control unit (pressure reduction amount control unit) 79 Processing unit (correction means)

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshinori Toya 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Inventor Takashi Kawanabe 2-5 Keihan Hondori, Moriguchi City, Osaka Prefecture No. 5 Sanyo Electric Co., Ltd. (72) Inventor Atsumi Ishikawa 2-5-5 Keihan Hondori, Moriguchi City, Osaka Prefecture Sanyo Electric Co., Ltd. (72) Inventor Yoshitaka Hara Keihan Hondori, Moriguchi City, Osaka Prefecture 2-5-5 Sanyo Electric Co., Ltd.

Claims (4)

[Claims] 1. At least two refrigerants having different characteristics are used.
A mixed refrigerant that is a mixture of more than one type is compressed by a compressor, a condenser,
In an electric device configured to circulate in a refrigerant circuit including an evaporator and configured to change the capacity of the compressor according to a load, based on the operating state of the refrigerant circuit by the operation of the compressor. A pressure reduction amount control unit that generates an output for setting the pressure reduction amount of the pressure reduction device, a mechanism that adjusts the pressure reduction device so that the pressure reduction amount set in response to this output is obtained, and the refrigerant circuit. An electric device comprising: a correction unit that corrects an output from the depressurization amount control unit based on a mixing ratio of the circulating mixed refrigerant. 2. The electric device according to claim 1, wherein the correction unit functions when the mixing ratio of the mixed refrigerant exceeds a predetermined range. 3. The mixing ratio of the mixed refrigerant is a mixing ratio of a specific refrigerant in the mixed refrigerant circulating in the refrigerant circuit,
3. The electric device according to claim 2, wherein the correction unit functions in a direction in which the decompression amount of the decompression device decreases as the mixing ratio increases. 4. The electric device according to claim 3, wherein the correction unit functions after a predetermined time has elapsed from the start of operation of the compressor.