JP2000213822A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a feeling due to an increase in an amount of dehumidifica tion and a COP (energy consumption efficiency) by switching a throttle in a cooling rating and a cooling intermediate interlocking with an operating fre quency. SOLUTION: In an air conditioner, a two-way valve 6a is connected in parallel with a heating capillary 5. Upon cooling operation, the two-way valve 6a is opened. Upon cooling intermediate operation in which a cooling operating frequency is lowered in accordance with a load, the two-way valve 6a is closed. Thus, upon cooling operation, a refrigerant is caused to flow through the two- way valve 6a. Upon cooling intermediate operation, the refrigerant is caused to flow through the heating capillary 5. A throttle device through which the refrigerant passes can be switched upon cooling operation and upon cooling intermediate operation. Thus, the low pressure of a refrigerating cycle upon cooling intermediate operation can be lowered and a feeling can be improved due to an increase in an amount of dehumidification.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttling device for an air conditioner, and more particularly to the comfort of an air conditioner when the load decreases during cooling operation and the operating frequency of a compressor decreases.

[0002]

2. Description of the Related Art FIG. 4 is a circuit diagram showing an example of a refrigeration cycle of a conventional air conditioner (air conditioner). During normal cooling rated operation (hereinafter referred to as “cooling rated”),
The refrigerant discharged from the compressor 1 passes through the four-way valve 2 and passes through the arrow a.
It flows in the direction, is branched into two in the outdoor heat exchanger 3, and passes through a cooling expansion device (hereinafter, referred to as "cooling capi") 4. Further, the refrigerant flows in the direction of arrow c, passes through the check valve 11 as it is, and flows into the indoor heat exchanger 7.

During normal heating rated operation (hereinafter referred to as "heating rated")
That. In), the refrigerant flows in reverse. That is, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 and flows in the direction of the arrow b, flows through the indoor heat exchanger 7 and flows in the direction of the arrow e, and is a heating expansion device (hereinafter, referred to as a “heating heating device”). ) Pass through 5.

[0004]

However, in order to realize an inverter air conditioner capable of controlling the throttle according to the operating frequency of the compressor in the conventional air conditioner as described above, if the throttle device is a capillaries, , Because it has only the most suitable capillaries for cooling and heating ratings,
It is generally known that when the cooling operation frequency is reduced in accordance with the load during operation (hereinafter, referred to as “cooling intermediate”), the throttle amount tends to be insufficient.

[0005] When the amount of squeezing is insufficient, the low pressure of the refrigeration cycle increases, and in many cases, a sufficient amount of dehumidification cannot be ensured. In such a case, between the cooling rating and the cooling middle,
Switching the throttling device has been very difficult with a conventional method using a check valve.

As another method, it is conceivable to use an electronic expansion valve, but in this case, there is a problem that the cost of the valve and the control device is high.

The present invention solves the above-mentioned conventional problems, and improves the feeling by increasing the dehumidification amount by switching the throttle between the cooling rating and the middle of the cooling in accordance with the operating frequency. It is an object of the present invention to provide an air conditioner capable of improving COP (energy consumption efficiency).

[0008]

In order to achieve the above object, an air conditioner of the present invention comprises a compressor, a four-way valve, an outdoor heat exchanger, a throttle device for cooling operation, a throttle device for heating operation, and an indoor device. A heat exchanger is sequentially connected in a ring with a pipe, comprising a refrigeration cycle in which a refrigerant circulates, an air conditioner serving as a cooling and heating device that varies the operating frequency of the compressor according to a load,
A two-way valve connected in parallel to the heating operation throttle device, wherein the two-way valve is opened during the cooling operation, and the two-way valve is closed during the cooling intermediate operation in which the cooling operation frequency is reduced according to the load. Thus, the switching of the expansion device through which the refrigerant passes between the cooling operation and the intermediate cooling operation is performed.

According to the air conditioner as described above, the low pressure of the refrigeration cycle during the intermediate cooling operation can be reduced, and the feeling can be improved by increasing the amount of dehumidification.

In the air conditioner, it is preferable that during the cooling intermediate operation, the refrigerant passes through the cooling operation expansion device and the heating operation expansion device. According to the air conditioner as described above, the throttle amount during the intermediate cooling operation is the same as the throttle amount during the heating operation, and the low pressure of the refrigeration cycle can be reduced during the intermediate cooling operation, and the amount of dehumidification increases. Feeling can be improved.

An electronic control unit is provided for setting a frequency during the intermediate cooling operation of the compressor. When the frequency during the intermediate cooling operation is reached, the two-way valve is closed by a signal from the electronic control unit. It is preferable to switch the expansion device through which the refrigerant passes between the cooling operation and the intermediate cooling operation.

[0012] The two-way valve may be a first two-way valve, and an electronic control unit in which a frequency is set during a cooling intermediate operation of the compressor, and the first and second valves connected in series to the heating operation expansion device. A second two-way valve connected in parallel with the two-way valve, and a heating intermediate expansion device and a cooling intermediate operation expansion device connected in parallel to the second two-way valve. During operation, the first two-way valve is opened and the second two-way valve is closed, so that the refrigerant that has passed through the cooling operation throttle device flows through the first two-way valve, and the cooling intermediate operation At the time of the time, by closing the first two-way valve and the second two-way valve by a signal from the electronic control device,
It is preferable that the refrigerant having passed through the cooling operation throttle device flows through the cooling intermediate operation throttle device.

According to the air conditioner as described above, during the intermediate cooling operation, the refrigerant flows through the throttle device for the intermediate cooling operation, so that the expansion device for the intermediate cooling operation can be used exclusively. With the improvement, optimization of dehumidification performance becomes possible, and more comfortable air conditioner operation becomes possible.

Further, it is preferable that the first two-way valve is opened when not energized, and the second two-way valve is closed when not energized.

According to the above-described air conditioner, during the cooling operation, the first two-way valve and the second two-way valve are de-energized, so that the power consumption is reduced and the COP is prevented from lowering. can do.

Further, the two-way valve is a first two-way valve, and an electronic control unit in which a frequency is set during a cooling intermediate operation of the compressor, and the first and second valves connected in series to the heating operation expansion device. A second two-way valve connected in parallel with the two-way valve of
The first two-way valve includes a main valve, and a bypass passage connected in parallel to the main valve and through which the refrigerant flows when the main valve is closed,
During the cooling operation, the main valve of the first two-way valve is opened and the second two-way valve is closed, so that the refrigerant that has passed through the cooling operation throttle device is supplied to the main valve of the first two-way valve. When the frequency at the time of the cooling intermediate operation is reached, the main valve of the first two-way valve and the second two-way valve are closed by a signal from the electronic control device, whereby the throttle device for cooling operation is It is preferable that the refrigerant that has passed through the bypass flow path.

According to the air conditioner as described above, the expansion device during the intermediate cooling operation can be dedicated, and the COP during the intermediate cooling operation can be improved, and the dehumidification performance can be optimized. Air conditioner operation becomes possible. Moreover,
There is no need to separately provide a throttle device for the cooling intermediate operation, and it is possible to suppress an increase in cost.

Further, according to each of the above air conditioners, the operation can be performed at a lower cost than when an electronic expansion valve is used.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The air conditioner according to each of the following embodiments is an inverter air conditioner that is used for both cooling and heating, and includes an indoor fan motor, an outdoor fan motor, an electronic control device that varies the operating frequency of the compressor, and a drive circuit thereof. The operating frequency of the motor and the compressor varies according to the load.

(Embodiment 1) FIG. 1 is a circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 1 of the present invention. During the cooling operation, the refrigerant discharged from the compressor 1 is supplied to the four-way valve 2.
, Flows in the direction of arrow a, is branched into two by the outdoor heat exchanger 3, and passes through the cooling capillaries 4.

At the cooling rating, the two-way valve 6a is opened, and the refrigerant flows in the direction of arrow c, passes through the two-way valve 6a as it is, and flows into the indoor heat exchanger 7. At the heating rating, the refrigerant flows in reverse. That is, the refrigerant discharged from the compressor 1 passes through the four-way valve 2, flows in the direction of arrow b, flows through the indoor heat exchanger 7 in the direction of arrow e, and passes through the heating cap 5.

Generally, when comparing the amount of throttle of the cooling capillaries and the amount of throttle of the heating capillaries, the amount of throttle of the heating capillaries is about 30% larger.

The opening / closing patterns of the two-way valve 6a at the cooling rating, the cooling middle, and the heating rating are shown in Table 1 below.
"Open" indicates that the two-way valve 6a is open and the refrigerant flows through the two-way valve 6a, and "closed" indicates that the two-way valve 6a is closed and the flow of the refrigerant passing through the two-way valve 6a is stopped. The state is shown. The opening and closing control of the two-way valve 6a is performed by the electronic control unit 8.

[0024]

[Table 1] Cooling rating Cooling middle Heating rating Two-way valve Open (energized) Closed (non-energized) Closed (non-energized) In the middle of cooling, the two-way valve 6a is closed, and the refrigerant flows in the direction of arrow d.
Direction, and further flows through the heating capillaries 5, and the throttle flow rate is smaller than that of the cooling capillaries 4. That is, the throttle amount in the middle of the cooling is equal to the throttle amount of the heating rating.

For this reason, it is possible to reduce the low pressure of the refrigeration cycle in the middle of cooling, and it is possible to improve the feeling by increasing the amount of dehumidification.

(Embodiment 2) FIG. 2 is a circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 2 of the present invention. In the present embodiment, a second two-way valve 9 is installed on the inlet side of the heating cap 5 (during cooling operation), separately from the first two-way valve 6b. In addition, a cooling intermediate expansion device (hereinafter, referred to as “cooling intermediate cap”) 10 is installed in parallel with the second two-way valve 9. The cooling intermediate capi 10 also functions as a throttle device during the heating operation in which the refrigerant flows in the direction of arrow e.

Table 2 below shows the opening / closing patterns of the first two-way valve 6b and the second two-way valve 9 in the cooling rating, the cooling middle, and the heating rating.

[0028]

[Table 2] Cooling rating Cooling intermediate Heating rating First two-way valve Open (energized) Closed (non-energized) Closed (non-energized) Second two-way valve Closed (non-energized) Closed (non-energized) Open (energized) The cooling intermediate operation frequency is defined in advance as a set value in the electronic control unit 8, and when the cooling intermediate operation frequency is reached, the first two-way valve 6b is automatically connected to the electronic control unit 8 by an electric signal from the electronic control unit 8. The second two-way valve 9 is de-energized, and both valves are closed to stop the flow of the refrigerant.

For this reason, in the middle of cooling, the refrigerant flows through the cooling intermediate capillaries 10 (in the direction of arrow c), and the capillaries in the middle of cooling can be dedicated, and the COP in the middle of cooling can be improved and the dehumidifying performance can be optimized. And more comfortable air-conditioning operation.

Embodiment 3 A circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 3 is shown in FIG.
Is the same as the circuit diagram of the refrigeration cycle of the air conditioner according to the above. Embodiment 3 is different from Embodiment 2 in Embodiment 2.
The first two-way valve 6b is of a type that opens when energized, whereas the third embodiment is of a type that closes when energized.

Table 3 below shows the opening / closing patterns of the first two-way valve 6b and the second two-way valve 9 in the cooling rating, the cooling middle, and the heating rating.

[0032]

[Table 3] Cooling rating Cooling middle Heating rating First two-way valve Open (non-energized) Closed (energized) Closed (energized) Second two-way valve Closed (non-energized) Closed (non-energized) Open (energized) Cooling The intermediate operating frequency is defined in advance as a set value in the electronic control unit 8, and when the operating frequency reaches the cooling intermediate operating frequency, the first two-way valve 6b is automatically energized by an electric signal from the electronic control unit 8. Then, the second two-way valve 9 is de-energized, and both of them close the valves to stop the flow of the refrigerant.

For this reason, as in the second embodiment, the refrigerant flows through the cooling intermediate capillaries 10 (in the direction of arrow c), so that the capillaries in the middle of the cooling can be dedicated, and the COP in the middle of the cooling can be improved and the dehumidifying performance can be improved. Optimization of air conditioning becomes possible, and comfortable air-conditioning operation becomes possible.

Further, as shown in Table 3, in the cooling rating, the first two-way valve 6b and the second two-way valve 9 are de-energized, so that the power consumption is reduced and the cooling rating is reduced. C
OP is improved as compared with the second embodiment.

(Embodiment 4) FIG. 3 is a circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 4 of the present invention. In the present embodiment, a bypass two-way valve 6c is used as the first two-way valve instead of a normal two-way valve. The bypass two-way valve 6c is a valve that is opened when energized and has a main valve 6d and a bypass passage 6e for a small flow rate inside.

When power is not supplied, the main valve 6d closes and refrigerant flows through the bypass 6e. This bypass 6e is used as a cooling intermediate capi. The bypass also functions as a throttle device during the heating operation in which the refrigerant flows in the direction of arrow e.

Table 4 shows the opening / closing patterns of the bypass two-way valve 6c and the second two-way valve 9 in the cooling rating, the cooling middle, and the heating rating.

[0038]

[Table 4] Cooling rating Cooling middle Heating rating Bypass two-way valve Open (energized) Closed (non-energized) Closed (non-energized) Second two-way valve Closed (non-energized) Closed (non-energized) Open (energized) Cooling intermediate The operating frequency is defined in advance as a set value in the electronic control unit 8. When the operating frequency reaches a cooling intermediate operating frequency, the bypass two-way valve 6 c and the second two-way valve are automatically controlled by an electric signal from the electronic control unit 8. The one-way valve 9 is de-energized, both valves are closed, and the refrigerant flows through the bypass 6e (direction of arrow c).

For this reason, similarly to Embodiments 2 and 3, the capillaries in the middle of cooling can be dedicated, and the COP in the middle of cooling can be improved, and the dehumidification performance can be optimized.
Comfortable air conditioner operation becomes possible. In addition, there is no need to separately provide a cooling intermediate capi, so that an increase in cost can be suppressed.

[0040]

As described above, according to the air conditioner of the present invention, the two-way valve is connected in parallel with the throttle device for the heating operation, and the two-way valve is opened and closed, so that the cooling operation and the cooling intermediate operation can be performed. It is possible to switch the expansion device through which the refrigerant passes,
As the COP is improved, the low pressure of the refrigeration cycle during the cooling intermediate operation can be reduced, and the feeling can be improved by increasing the amount of dehumidification.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 1 of the present invention.

FIG. 2 is a circuit diagram of a refrigeration cycle of the air conditioner according to Embodiment 2 of the present invention.

FIG. 3 is a circuit diagram of a refrigeration cycle of an air conditioner according to Embodiment 4 of the present invention.

FIG. 4 is a circuit diagram of an example of a refrigeration cycle of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Cooling expansion device 5 Heating expansion device 6a Two-way valve 6b First two-way valve 6c Bypass two-way valve 6d Main valve 6e Bypass path 7 Indoor heat exchanger 8 Electronic control device 9 second two-way valve 10 cooling intermediate expansion device

Claims (6)

[Claims] 1. A refrigeration cycle in which a compressor, a four-way valve, an outdoor heat exchanger, a cooling operation expansion device, a heating operation expansion device, and an indoor heat exchanger are sequentially connected in a loop with piping, and a refrigerant circulates. A cooling / heating air conditioner that varies an operation frequency of the compressor according to a load, the air conditioner having a two-way valve connected in parallel to the heating operation expansion device, and the two-way valve during cooling operation. By opening the two-way valve during the cooling intermediate operation in which the cooling operation frequency is reduced according to the load, the switching of the expansion device through which the refrigerant passes between the cooling operation and the cooling intermediate operation is performed. Air conditioner. 2. The air conditioner according to claim 1, wherein during the cooling intermediate operation, the refrigerant passes through the cooling operation expansion device and the heating operation expansion device. 3. An electronic control device in which a frequency during the intermediate cooling operation of the compressor is set, and when the frequency during the intermediate cooling operation is reached, the two-way valve is closed by a signal from the electronic control device. The air conditioner according to claim 1, wherein the expansion device through which the refrigerant passes is switched between a cooling operation and an intermediate cooling operation. 4. The electronic control unit, wherein the two-way valve is a first two-way valve, a frequency of which is set during a cooling intermediate operation of the compressor, and the first one in series with the throttling device for heating operation. A second two-way valve connected in parallel with the two-way valve, and a heating intermediate expansion device and a cooling intermediate operation expansion device connected in parallel to the second two-way valve. During operation, the first two-way valve is opened and the second two-way valve is closed, so that the refrigerant that has passed through the cooling operation throttle device flows through the first two-way valve, and the cooling intermediate operation When the frequency becomes the time, by closing the first two-way valve and the second two-way valve by a signal from the electronic control device, the refrigerant that has passed through the cooling operation throttle device is used for the cooling intermediate operation. The air conditioner according to claim 1, wherein the air conditioner flows through a throttle device. 5. The first two-way valve opens when not energized, and the second two-way valve closes when not energized.
The air conditioner according to item 1. 6. The first two-way valve, wherein the two-way valve is a first two-way valve, and an electronic control unit in which a frequency during a cooling intermediate operation of the compressor is set; And a second two-way valve connected in parallel with the two-way valve. The first two-way valve is connected in parallel with the main valve, and the refrigerant flows when the main valve is closed. By providing a bypass flow path, and opening the main valve of the first two-way valve and closing the second two-way valve during the cooling operation, the refrigerant that has passed through the cooling operation expansion device is the first refrigerant. Flow through the main valve of the two-way valve, and when the frequency at the time of the cooling intermediate operation is reached, the main valve of the first two-way valve and the second
2. The air conditioner according to claim 1, wherein by closing the two-way valve, the refrigerant that has passed through the cooling operation expansion device flows through the bypass passage. 3.