JP2643708B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner capable of cooling and dehumidifying operations.

[0002]

2. Description of the Related Art A conventional air conditioner capable of dehumidifying operation (for example, see Japanese Utility Model Laid-Open No. 3-27571) will be described with reference to FIG. This air conditioner has a compressor 51
While the cooling operation is performed by condensing the refrigerant discharged from the outdoor heat exchanger 52 and evaporating the refrigerant in the indoor heat exchanger 53, the heating operation is performed by circulating the refrigerant in the opposite manner to the above. I have. In this case, the indoor heat exchanger 53 includes two heat exchangers 53a for performing the dehumidifying operation.
53b, the two heat exchangers 53a, 53
A parallel circuit of the on-off valve 54 and the capillary tube 55 is interposed between b. As shown in FIG. 6, the open / close valve 54 has a shape memory spring 56, a bias spring 57, a spacer 58 that moves according to the magnitude relationship between the forces of the two springs 56, 57, and is slidably supported by the spacer 58. When the low-temperature refrigerant flows, the shape memory spring 56 is in a contracted state and is opened as shown in FIG. 6, while when the high-temperature refrigerant flows, the shape memory spring 56 is opened. In the extended state, the valve is closed as shown in FIG.

When the dehumidifying operation is performed in the air conditioner, the refrigerant discharged from the compressor 51 is supplied to the outdoor heat exchanger 52 (the outdoor fan 60 is OFF), and the refrigerant is stored in the bypass passage 61 through the heat storage heat source. It is reheated via the exchanger 62 and supplied to the indoor heat exchanger 53. Then, the shape memory spring 56 of the on-off valve 54 expands and closes (FIG. 7), and the refrigerant flows through the capillary tube 55. As a result, condensation occurs in the indoor heat exchanger 53a on the upstream side, and the indoor heat exchanger 5
Evaporation occurs at 3b, thereby cooling and dehumidifying the indoor air, and then performing a dehumidifying operation in which the dehumidified air is heated to about room temperature and returned to the room. In the opening / closing valve 54 of the air conditioner, the valve body 59 moves in the valve opening direction due to the flow of the refrigerant during the heating operation, so that the valve closing operation due to the temperature rise is prevented.

[0004]

The air conditioner described above has a disadvantage that it takes a relatively long time to perform the valve closing operation of the on-off valve 54 and shift to the dehumidifying operation. This is because the shape memory spring 56 is heated by a gas refrigerant having a small heat capacity, so that a sufficient temperature rising speed cannot be obtained. When the heat storage heat exchanger 62 is used in the above-described manner for the purpose of quickly performing the valve closing operation, the reversible solenoid valve 63 provided in the bypass path 61 needs to be used. This causes an increase in device cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional disadvantages, and has as its object to provide an air conditioner capable of performing a quick transition to a dehumidifying operation without complicating the structure of the apparatus. To provide machines.

[0006]

In the air conditioner of the present invention, a compressor 1, an outdoor heat exchanger 3, an electric expansion valve 4, and an indoor heat exchanger 5 are connected in this order to form a refrigerant circulation path. The indoor heat exchanger 5 is divided into a first indoor heat exchanger 5a located on the side of the electric expansion valve 4 and a second indoor heat exchanger 5b located on the side of the compressor 1, so that both heat exchangers are provided. 5a and 5b are connected in series by a connection path 9 and the on-off valve 1 is connected in parallel.
0 and the pressure reducing mechanism 11 are interposed in the connection path 9 to perform a cooling operation in which the indoor heat exchanger 5 functions as an evaporator when the on-off valve 10 is in an open state.
In the air conditioner configured to perform a dehumidifying operation in which the first indoor heat exchanger 5a functions as a condenser and the second indoor heat exchanger 5b functions as an evaporator in the valve closed state, The valve 10 has a first passage 12 connected to the first indoor heat exchanger 5a, a second passage 13 connected to the second indoor heat exchanger 5b,
An internal flow path communicating with the first and second passages; a valve body for opening and closing the valve seat is reciprocally movable toward the first passage; And a bias spring 17 for urging the valve element 16 in the valve closing direction and a shape memory spring 18 for urging the valve element 16 in the valve opening direction. In the extended state, the valve body 16 is separated from the valve seat 15, and when a refrigerant having a temperature lower than that flows, the valve body 16 is contracted and the valve body 16 is moved to the valve seat 15.
Valve closing control means for closing the valve by contacting the opening and closing of the on-off valve 10, and further stopping the air supply to the indoor heat exchanger 5 for a predetermined time after starting the operation in the cooling state to close the on-off valve 10. 20 is provided.

Further, the air conditioner according to the second aspect is characterized in that the valve closing control means 20 performs control to gradually reduce the opening of the electric expansion valve 4 within the predetermined time.

[0008]

In the air conditioner of the first aspect, when the cooling operation is started in a state in which the air supply to the indoor heat exchanger 5 is stopped by the valve closing control means 20, the temperature of the refrigerant flowing through the indoor heat exchanger 5 is normally reduced. Lower than during the cooling operation. Then, the shape memory spring 18 is cooled to be in a contracted state, the on-off valve 10 is closed, and a transition to the dehumidifying operation is possible. In this case, since the shape memory spring 18 is given a temperature change by a liquid refrigerant having a larger heat capacity than a gas refrigerant or a gas-liquid mixed refrigerant, the temperature change occurs promptly.

Further, in the air conditioner of the second aspect, since the temperature of the refrigerant can be reliably and promptly lowered, the closing operation of the on-off valve 10 necessary for shifting to the dehumidifying operation can be reliably and promptly performed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of the air conditioner of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the circuit configuration. In FIG. 1, 1 is a compressor, 2 is a four-way switching valve, 3 is an outdoor heat exchanger,
Reference numeral 4 denotes an electric expansion valve, and reference numeral 5 denotes an indoor heat exchanger. These are connected to each other to form a refrigerant circulation path 6. 7 indicates an outdoor fan, and 8 indicates an indoor fan. The indoor heat exchanger 5 is divided into a first indoor heat exchanger 5a located on the electric expansion valve 4 side and a second indoor heat exchanger 5b located on the compressor 1 side. The devices 5a and 5b are connected in series by a connection path 9. An on-off valve 10 is interposed in the connection path 9, and a capillary tube (decompression mechanism) 11 is connected to the on-off valve 10 in parallel.

As shown in FIG. 2, the on-off valve 10 includes a first passage 12 connected to the first indoor heat exchanger 5a,
It includes a second passage 13 connected to the indoor heat exchanger 5b, and an internal passage 14 communicating the two passages 12, 13.
A valve seat 15 is formed in the internal flow path 14. A valve element 16 is disposed in the internal flow path 14 at a position closer to the first passage 12 than the valve seat 15 so as to be slidable reciprocally, and the valve element 16 abuts on and separates from the valve seat 15. By opening and closing valve 1
A valve closing and valve opening operation of 0 can be performed. A bias spring 17 is provided at a position closer to the first passage 12 than the valve body 16, and the bias spring 17 urges the valve body 16 in the valve closing direction. A shape memory spring 18 is disposed between the valve body 16 and the valve seat 15, and urges the valve body 16 by the shape memory spring 18 in the valve opening direction. This shape memory spring 18 is made of a shape memory alloy,
It is made of a shape memory resin or the like, and is in an expanded state in a temperature range similar to the temperature of the refrigerant flowing through the indoor heat exchanger 5 during the cooling operation, so that the on-off valve 10 is operated by the force of the shape memory spring 18. Although the valve is opened as shown in FIG. 2, when the temperature further drops, the valve is in a contracted state, and as shown in FIG. 3, the valve is closed by the force of the bias spring 17. . Note that 2 in FIG.
Numeral 0 denotes a valve closing control means for controlling the valve closing operation of the on-off valve 10, the function of which will be described later.

Next, an operation state of the air conditioner will be described. First, as shown by the solid arrow A in FIG. 1, the refrigerant from the compressor 1 is condensed by the outdoor heat exchanger 3 and evaporated by the indoor heat exchanger 5 to perform a cooling operation.
Contrary to this, as shown by broken line B, the heating operation is performed by condensing in the indoor heat exchanger 5 and evaporating in the outdoor heat exchanger 3 as in the related art. In the dehumidifying operation, in the cooling operation mode, the outdoor fan 7 is stopped, the electric expansion valve 4 is fully opened, the on-off valve 10 is closed, the first indoor heat exchanger 5a condenses, and the second indoor heat exchanger is used. 5
b, the respective functions of evaporation are performed, the indoor fan 8 is driven, the indoor air cooled and dehumidified by the second indoor heat exchanger 5b is heated to about room temperature by the first indoor heat exchanger 5a, and This is done by returning the flow.

The point to be noted here is that the operation control by the valve closing control means 20 for closing the on-off valve 10 when starting the dehumidifying operation is different from the conventional one. Hereinafter, this point will be described with reference to FIG. First, the operation is started in the cooling operation mode. At this time, the inverter frequency of the compressor 1 is set high (80 Hz), the electric expansion valve 4 is also set to the control opening degree, and the indoor fan 8 is stopped. The outdoor fan 7 is kept in operation. Thereafter, the opening degree of the electric expansion valve 4 is reduced stepwise as shown in the figure. As a result of stopping the indoor fan 8 and gradually reducing the opening of the electric expansion valve 4 as described above, the temperature of the refrigerant flowing through the on-off valve 10 becomes lower than the refrigerant temperature during the cooling operation, and the shape memory is stored. The spring 18 is in a contracted state, the valve element 16 contacts the valve seat 15, and the on-off valve 10 is closed. At this time, since the shape memory spring 18 is cooled by the liquid refrigerant or the gas-liquid mixed refrigerant having a larger heat capacity than the gas refrigerant, the temperature is rapidly lowered, and the closing operation of the on-off valve 10 is performed quickly. Then, after a lapse of a sufficient time T for performing the valve closing operation, the electric expansion valve 4 is fully opened, the outdoor fan 7 is stopped, and then the inverter frequency of the compressor 1 is reduced to the steady operation frequency. Then, the indoor fan 8 is driven to start the dehumidifying operation. In this case, the refrigerant temperature rises with the start of the dehumidifying operation, the shape memory spring 18 of the on-off valve 10 is extended, and the valve body 16 is urged in the valve opening direction. In this case, a differential pressure of the refrigerant flow acts, and the valve closing state is maintained by the differential pressure.

From the above, in the above air conditioner, the transition to the dehumidifying operation can be performed more quickly than in the past,
In addition, since no particular configuration is required, an increase in device cost can be prevented. In particular, in the conventional on-off valve 54 shown in FIGS. 6 and 7, it is necessary to provide a special member called the spacer 58 in order to prevent the valve closing operation during the heating operation. Since such a member is unnecessary, the configuration can be simplified.

[0016]

As described above, in the air conditioner of the first aspect, the closing operation of the on-off valve is performed by using the liquid refrigerant or the gas-liquid mixed refrigerant having a larger heat capacity than the gas refrigerant. Thus, the shift to the dehumidifying operation can be quickly performed. In addition, since it is not necessary to add a special configuration for that purpose, it is possible to prevent an increase in apparatus cost.

According to the air conditioner of the second aspect, the transition to the dehumidifying operation can be performed more quickly and reliably.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment of the air conditioner of the present invention.

FIG. 2 is a sectional view showing an open state of an example of the on-off valve used in the above.

FIG. 3 is a sectional view showing a closed state of the on-off valve.

FIG. 4 is a time chart showing an operation control example in the air conditioner.

FIG. 5 is a circuit diagram of a conventional air conditioner.

FIG. 6 is a cross-sectional view showing an open state of an on-off valve used in a conventional air conditioner.

FIG. 7 is a sectional view of the on-off valve in a closed state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Outdoor heat exchanger 4 Electric expansion valve 5 Indoor heat exchanger 5a 1st indoor heat exchanger 5b 2nd indoor heat exchanger 6 Refrigerant circulation path 8 Indoor fan 9 Connection path 10 On-off valve 11 Capillary tube (decompression mechanism) 12) first passage 13 second passage 14 internal passage 15 valve seat 16 valve element 17 bias spring 18 shape memory spring 20 valve closing control means

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hidehiko Kataoka 1000 Oya, Okamotocho, Kusatsu-shi, Shiga 2 Daikin Industries, Ltd. Shiga Works

Claims (2)

(57) [Claims] 1. A refrigerant circuit is formed by sequentially connecting a compressor (1), an outdoor heat exchanger (3), an electric expansion valve (4), and an indoor heat exchanger (5). (5) a first indoor heat exchanger (5a) located on the electric expansion valve (4) side;
It is divided into a second indoor heat exchanger (5b) located on the compressor (1) side and both heat exchangers (5a) and (5b) are connected in series by a connection path (9), and are opened and closed in parallel. A cooling operation in which a valve (10) and a pressure reducing mechanism (11) are interposed in the connection path (9) and the indoor heat exchanger (5) functions as an evaporator when the on-off valve (10) is open. While the first indoor heat exchanger (5a) functions as a condenser and the second indoor heat exchanger (5b) functions as an evaporator when the on-off valve (10) is closed. In the air conditioner configured to perform the above, the on-off valve (10) is connected to the first indoor heat exchanger (5).
(a), a first passage (12) connected to the second indoor heat exchanger (5b), and an internal passage communicating the two passages (12) and (13). (14), a valve seat (15) is formed in the internal flow path (14), and a valve element (16) for opening and closing the valve seat (15) is provided on the first passage (12) side. A bias spring (17) arranged reciprocally to urge the valve body (16) in the valve closing direction.
And a shape memory spring (18) that urges in the valve opening direction, and the shape memory spring (18) is in an extended state at the temperature of the refrigerant flowing during the cooling operation, and the valve body (16)
Is separated from the valve seat (15), and when a refrigerant at a temperature lower than that flows, it is in a contracted state and the valve body (1) is contracted.
6) is brought into contact with the valve seat (15) to close the valve. Further, in order to close the on-off valve (10), after starting the operation in the cooling state, the indoor heat exchanger ( 5) An air conditioner comprising a valve closing control means (20) for stopping air supply to the air conditioner. 2. The air conditioner according to claim 1, wherein the valve closing control means (20) performs control to gradually reduce the opening of the electric expansion valve (4) within the predetermined time.