JPH0634220A - Air conditioning system - Google Patents

Abstract

PURPOSE:To quicken switchover to a dehumidifying operation based on a temperature-sensing change of a shape memory spring and to eliminate generation of a freezing sound in air conditioning system which conducts the dehumidifying operation by cooling and heating indoor air and in which the shape memory spring is used for an on-off valve for the dehumidifying operation. CONSTITUTION:A construction is made so that an on-off valve 10 is closed by a contraction change at the time of cooling of a shape memory spring used for the on-off valve 10 and thereby a dehumidifying operation is started. By a control means 20, for this purpose, a compressor 1 is stopped only for a first prescribed time in the state of a cooling operation, with an indoor fan 8 left operated, when the dehumidifying operation is started. In succession, the indoor fan 8 is stopped only for a second prescribed time, while the compressor 1 is operated, and the opening of an expansion valve 4 is lessened gradually, so as to remove dew sticking on an indoor heat exchanger 5 at the time of cooling. Thereafter a liquid refrigerant of a lower temperature than the one at the time of cooling is made to flow through the on-off valve 10.

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 heating / cooling operation and dehumidifying operation.

[0002]

2. Description of the Related Art As an air conditioner of this type, there is an air conditioner which has not been disclosed but is recently proposed by the present applicant as shown in FIG. 1 (Japanese Patent Application No. 3-57492). In this air conditioner, the configuration of the refrigerant circuit is substantially the same as that of the present invention, and therefore, description will be given with reference to FIGS. 1 to 3 according to the present invention for convenience. As shown in FIG. 1, this air conditioner includes a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, an expansion valve 4, a first indoor heat exchanger 5a, and a second indoor heat exchanger 5b in that order. The pipes 6a to 6f are connected to each other, and the on-off valve 10 and the capillary tube 11 as the pressure reducing means are connected in parallel between the first and second indoor heat exchangers 5a and 5b, and the on-off valve 10 is opened to heat both indoors. While performing the cooling and heating operations by operating the exchangers 5a and 5b as evaporators or condensers, the on-off valve 10 is closed to use the first indoor heat exchanger 5a as a condenser and the second indoor heat exchanger 5b as an evaporator. As a result, each of them works to perform dehumidifying operation.

As shown in FIG. 2, the opening / closing valve 10 includes a first passage 12 connected to the first indoor heat exchanger 5a,
Second passage 13 connected to the second indoor heat exchanger 5b
And an internal flow passage 14 having a valve seat 15 and connecting the passages 12 and 13 to each other, and a valve element 16 for opening and closing the valve seat 15 is reciprocally disposed on the first passage 12 side. The valve element 16 is biased in the valve closing direction by the bias spring 17 and in the valve opening direction by the shape memory spring 18. The shape memory spring 18 extends in contact with the refrigerant (0 ° C. or higher) flowing during the cooling operation, and the valve body 16 separates from the valve seat 15 to open the on-off valve 10 as shown in FIG. 18 contracts by contacting a refrigerant having a temperature (0 ° C. or less) lower than that of the refrigerant flowing during the cooling operation, and the valve element 16 contacts the valve seat 15 to close the on-off valve 10 as shown in FIG. .

In the above air conditioner, in order to perform the cooling operation, the expansion valve 4 is set to a predetermined opening degree, the refrigerant discharged from the compressor 1 is circulated as indicated by a solid arrow A in FIG. After being condensed in the vessel 3, it is evaporated in the indoor heat exchanger 5. At this time, in the on-off valve 10 between the first and second indoor heat exchangers 5a and 5b, the shape memory spring 18 is extended by the low temperature refrigerant (0 ° C. or higher) flowing from the first passage 12 side in FIG. Since it is opened as shown in the figure, both the indoor heat exchangers 5a and 5b work together as an evaporator, and the indoor fan 8 blows air to cool the room. On the contrary, in order to perform the heating operation, the four-way switching valve 2 is switched and the discharged refrigerant is circulated in the reverse direction as indicated by the broken arrow B in FIG. Then, the on-off valve 10 is opened as shown in the figure by the shape memory spring 18 being expanded by the high temperature refrigerant flowing from the second passage 13 side in FIG. 2 through the second indoor heat exchanger 5b, so that both indoor heat exchangers 5a are opened. Both 5b work as a condenser, and the indoor fan 8 blows air to heat the room.

On the other hand, in the dehumidifying operation, the four-way switching valve 2 is set to the same switching position as in the illustrated cooling mode, and the outdoor fan 7 is stopped.
By fully opening the expansion valve 4 and closing the on-off valve 10, the first indoor heat exchanger 5a on the upstream side of the capillary tube 11 functions as a condenser, and the second indoor heat exchanger 5b on the downstream side functions as an evaporator. The indoor air is first cooled and dehumidified by the second indoor heat exchanger 5b by the blowing of the indoor fan 8 and then heated to about room temperature by the first indoor heat exchanger 5a. At that time, control means (not shown) is used. (5) closes the on-off valve 10 by the control shown in FIG.

That is, the inverter frequency of the compressor 1 is high.
(80 Hz), in the cooling operation mode in which the expansion valve 4 is at the control opening and the outdoor and indoor fans 7 and 8 are in the operating state, the control means stops only the indoor fan 8 as shown at the beginning of FIG. At the same time, the opening degree of the expansion valve 4 is gradually reduced. Then, the temperature of the refrigerant passing through the on-off valve 10 becomes 0 ° C. or lower, which is lower than the temperature of the refrigerant during the cooling operation, and the shape memory spring 18 in contact with the refrigerant contracts as shown in FIG.
Comes into contact with the valve seat 15, and the on-off valve 10 is closed. here,
Since the shape memory spring 18 is cooled by the liquid refrigerant or the gas-liquid mixed refrigerant having a heat capacity larger than that of the gas refrigerant, the temperature of the shape memory spring 18 is rapidly lowered, and therefore the closing operation of the on-off valve 10 is quickly performed. Then, after a time T ₂ (see FIG. 5) sufficient for the valve closing operation has passed, the expansion valve 4 is fully opened, the outdoor fan 7 is stopped, and then the inverter frequency of the compressor 1 is set to the steady operating 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 in an expanded state, and the valve body 16 is biased in the valve opening direction. Since a differential pressure between the front and rear of the capillary tube 11 due to the flow of the refrigerant acts, the valve closed state is maintained by this differential pressure. As described above, the air conditioner according to the present applicant's recent proposal enables a quick transition to the dehumidifying operation without complicating the device configuration.

[0007]

Usually, the dehumidifying operation is often performed when the indoor humidity is high, such as during the rainy season, and the surface of the heat exchange fins of the indoor heat exchanger 5 during the cooling operation before the dehumidifying operation. Condensation often occurs on the. However, when shifting to the dehumidifying operation, the above-described air conditioner immediately stops the indoor fan 8 in the cooling operation mode as described in FIG. 5, gradually reduces the opening degree of the expansion valve 4, and opens and closes with the refrigerant. Valve 10
And cooling the first and second indoor heat exchangers 5a, 5b to 0 ° C or lower,
Since the shape memory spring 18 is contracted and the valve is closed, the condensed water on the surface of the indoor heat exchanger 5 freezes, which causes a problem that abnormal noise such as icing noise occurs.

Therefore, an object of the present invention is to eliminate the icing noise when shifting from the cooling operation to the dehumidifying operation by devising the control when closing the on-off valve between the first and second indoor heat exchangers. An object of the present invention is to provide an air conditioner capable of performing the above.

[0009]

In order to achieve the above object, the air conditioner of the present invention is, as illustrated in FIG.
Compressor 1, four-way switching valve 2, outdoor heat exchanger 3, expansion valve 4, first
The indoor heat exchanger 5a and the second indoor heat exchanger 5b are sequentially connected by pipelines 6a to 6f, and the first and second indoor heat exchangers 5a and 5b are connected.
The on-off valve 10 and the pressure reducing means 11 are connected in parallel with each other, and the on-off valve 10 is opened to open both the indoor heat exchangers 5a, 5
While b is used as an evaporator or a condenser to perform cooling and heating operations, the on-off valve 10 is closed and the first indoor heat exchanger 5a is used as a condenser, and the second indoor heat exchanger 5b is used as an evaporator. In the ones that work individually to perform dehumidifying operation,
The on-off 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, and a valve seat 15, Passage 12,
And an internal flow path 14 communicating with the first flow path 1.
A valve body 16 for opening and closing the valve seat 15 is reciprocally arranged on the 2 side, and the valve body 16 is closed by a bias spring 17 in a valve closing direction.
The shape memory springs 18 are biased in the valve opening direction, respectively, and the shape memory springs 18 extend in contact with the refrigerant flowing during the cooling operation to separate the valve element 16 from the valve seat 15 while the cooling operation is performed. The valve body 16 is brought into contact with the valve seat 15 by contracting by contacting a refrigerant having a temperature lower than that of the circulating refrigerant, and further, in order to shift to the dehumidifying operation, the on-off valve 10 is closed. During the cooling operation in order to operate the valve, the compressor 1 is stopped while the indoor fan 8 is operating for the first predetermined time T ₁ , and then the indoor fan 8 is stopped and compressed for the second predetermined time T _2. Control means 2 for operating the machine 1
It is characterized in that 0 is provided. It should be noted that the control means 20 of the air conditioner may also perform control for gradually reducing the opening degree of the expansion valve 4 within the second predetermined time T ₂ .

[0010]

[Operation] Now, during the cooling operation, the first functioning as an evaporator,
It is assumed that dew condensation occurs on the surfaces of the second indoor heat exchangers 5a and 5b. In order to close the opening / closing valve 10 between the indoor heat exchangers 5a and 5b in order to shift to the dehumidifying operation, the control means 20 first operates the compressor 1 while operating the indoor fan 8 for the _first predetermined time T _1. Stop. Then, the two indoor heat exchangers 5a, 5b in which the supply of the low-temperature liquid refrigerant from the compressor 1 via the outdoor heat exchanger 3 and the expansion valve 4 is stopped, while the cooling action is stopped,
Since the indoor fan 8 continues to blow indoor air, the dew condensation on the surfaces of both indoor heat exchangers 5a and 5b is evaporated and eliminated. The control means 20 then stops the indoor fan 8 for a second predetermined time and operates the compressor 1. Then, the low-temperature liquid refrigerant is supplied to both the indoor heat exchangers 5a and 5b again, but since the heat exchange is not performed by stopping the indoor fan 8, the temperature of the refrigerant is lower than that in the normal cooling operation. It is below zero. As a result, the shape memory spring 18 contracts due to cooling, the valve body 16 contacts the valve seat 15, and the on-off valve 10 closes. At this time, the temperatures of both indoor heat exchangers 5a and 5b are also below zero, but since there is no dew condensation on the surface, the freezing does not occur and no abnormal noise such as icing noise occurs.

Thus, when the expansion valve 4 is fully opened and the outdoor fan 7 is stopped while the indoor fan 8 is driven and the compressor 1 is driven at a low speed, all the circulating refrigerant is decompressed in parallel with the on-off valve 10. Since the first indoor heat exchanger 5a on the upstream side functions as a condenser and the second indoor heat exchanger 5b on the downstream side functions as an evaporator, the dehumidifying operation starts. . The refrigerant temperature rises with the start of the dehumidifying operation, and the shape memory spring 18 of the on-off valve 10 expands to cause the valve body 1 to move.
6 is urged in the valve opening direction, but a differential pressure between the front and rear of the pressure reducing means 11 due to the refrigerant flow acts on the valve element 16, so that the valve closed state is maintained by this differential pressure. The control means 20
And if those performed gradually reducing controlling the opening of the expansion valve 4 in the second within a predetermined time T _2, so quickly and reliably perform the reduction of the coolant temperature, the required time of transition to the dehumidifying operation The closing operation of the opening / closing valve 10 can be performed quickly and reliably.

[0012]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a refrigerant circuit diagram showing an example of the air conditioner of the present invention. This air conditioner has the same configuration as the air conditioner according to the applicant's proposal already described with reference to the figure, except for the configuration of the control means, and therefore description of the same members will be omitted. As shown in FIG. 4, the control means 20 keeps the indoor fan 8 running for a _first predetermined time T ₁ in order to close the opening / closing valve 10 in order to shift to the dehumidifying operation during the cooling operation, and the compressor is operated. 1 is stopped, then the indoor fan 8 is stopped for a _second predetermined time T ₂ , the compressor 1 is operated, and the opening degree of the expansion valve 4 is gradually reduced.

The air conditioner configured as described above operates as follows. First, when performing the cooling operation, both the outdoor and indoor fans 7 and 8 are driven to set the expansion valve 4 to a predetermined opening degree, and the refrigerant discharged from the compressor 1 is circulated as indicated by a solid arrow A in FIG. After being condensed in the outdoor heat exchanger 3, it is evaporated in the indoor heat exchanger 5. On the contrary, when performing the heating operation, the four-way switching valve 2 is switched to reversely circulate the discharged refrigerant as shown by the broken line arrow B in FIG. 1, and is condensed in the indoor heat exchanger 5 and then in the outdoor heat exchanger 3. Evaporate. In both heating and cooling operation,
The on-off valve 10 between the first and second indoor heat exchangers 5a and 5b is fully opened, and both indoor heat exchangers 5a and 5b work as an evaporator or a condenser, but the valve opening operation is This is as described in the conventional example with reference to FIGS.

Next, the transition from the cooling operation to the dehumidifying operation is
It is performed as follows. In this case, it is assumed that the inside of the room is humid and dew condensation occurs on the surfaces of the heat exchange fins of the first and second indoor heat exchangers 5a and 5b that function as evaporators in the cooling operation in the previous stage. Control means 20, to close the on-off valve 10 between the two indoor heat exchangers 5a, 5b in order to shift to the dehumidifying operation from the cooling operation, as shown in FIG. 4, first, a first predetermined amount of time T ₁ chamber The compressor 1 is stopped while the fan 8 is operating. Then, both indoor heat exchangers 5a, 5b of the low temperature liquid refrigerant passing from the compressor 1 to the outdoor heat exchanger 3 and the expansion valve 4
Supply to the two indoor heat exchangers 5a, 5b
Stops the cooling action, but the indoor fan 8 continues to blow indoor air, so that the dew condensation on the fin surfaces of both indoor heat exchangers 5a and 5b is evaporated. Then, the control means 20
As shown in FIG. 4, the indoor fan 8 is stopped for the second predetermined time T ₂ , the compressor 1 is operated, and the opening degree of the expansion valve 4 is gradually reduced. Then, the low-temperature liquid refrigerant is supplied again to both the indoor heat exchangers 5a and 5b, but since the heat exchange with the indoor air is not performed due to the stop of the indoor fan 8, the temperature of the refrigerant is in the normal cooling operation ( (0 ° C or higher) to 0 ° C or lower.
As a result, the shape memory spring 18 of the on-off valve 10 contracts due to cooling, the valve body 16 contacts the valve seat 15 (see FIG. 3), and the on-off valve 10 closes. At this time, the temperature of both the indoor heat exchangers 5a and 5b also becomes 0 ° C. or less, but since there is no dew condensation on the fin surface, the freezing does not occur, and no unusual noise such as icing noise occurs unlike the conventional case. .

When the second predetermined time T ₂ has elapsed, the control means 20 fully opens the expansion valve 4 and stops the outdoor fan 7, and thereafter lowers the inverter frequency of the compressor 1 to a steady operating frequency. Then, the indoor fan 8 is driven. Then, all the circulating refrigerant flows through the capillary tube 11 parallel to the closed on-off valve 10 and is expanded and decompressed there. Therefore, the first indoor heat exchanger 5a on the upstream side is the condenser and the second indoor heat exchanger 5a on the downstream side is the second indoor heat exchanger 5a. The indoor heat exchangers 5b each work as an evaporator, and the dehumidifying operation starts. Note that the refrigerant temperature rises with the dehumidifying operation, the shape memory spring 18 of the on-off valve 10 expands and urges the valve element 16 in the valve opening direction, but the valve element 16 is moved forward and backward of the capillary tube 11 by the refrigerant flow. Since a differential pressure between them acts, the valve closed state is maintained by this differential pressure. In this embodiment, in addition to stopping the indoor fan 8 while operating the compressor 1 only for the second predetermined time T ₂ , the opening degree of the expansion valve 4 is gradually reduced, so that the refrigerant temperature is reduced to 0 ° C. or lower. Open / close valve 10 that can be quickly and reliably reduced and is necessary for shifting to dehumidification operation.
There is an advantage that the valve closing operation can be performed quickly and surely. The gradual reduction control of the opening degree of the expansion valve 4 by the control means 20 can be omitted, and even in that case, the generation of icing noise due to the freezing of the dew condensation water on the fin surface of the indoor heat exchanger 5 is eliminated. be able to.

[0016]

As is apparent from the above description, the air conditioner of the present invention includes a compressor, a four-way switching valve, an outdoor heat exchanger, an expansion valve, a first indoor heat exchanger and a second indoor heat exchanger. In which the on-off valve and the pressure reducing means are connected in parallel to each other between the first and second indoor heat exchangers, one end of the on-off valve is connected to the first indoor heat exchanger, A valve element is reciprocally disposed on one end side of an internal flow path having a valve seat, the other end of which communicates with the second indoor heat exchanger, and the valve element is closed by a bias spring in a valve closing direction and has a shape memory. The shape memory springs are each urged in the valve opening direction by springs and extend in contact with the refrigerant flowing during the cooling operation to lift the valve body to open the valve, while the refrigerant having a temperature lower than that of the refrigerant is opened. When the valve body is seated, the valve body is closed and the valve is automatically closed by the change of the refrigerant temperature. When both valves are opened, both indoor heat exchangers work as evaporators or condensers to perform cooling and heating operation, while the same on-off valve is closed, the first indoor heat exchanger is condensed and the second indoor heat exchanger is evaporated. Dehumidifying operation by operating each as a container, and during the cooling operation by the control means, the compressor is stopped while the indoor fan is operating for the first predetermined time, and then the indoor fan is stopped for the second predetermined time. In addition, the compressor is operated and the on-off valve is closed to shift to the dehumidifying operation.Therefore, when shifting to the dehumidifying operation, the dew condensation that has adhered to the surface of the indoor heat exchanger during the cooling operation in the previous stage is performed. It can be removed by evaporation, and the generation of ice noise during transfer can be eliminated. If the opening degree of the expansion valve is gradually reduced within the second predetermined time by the control means, the refrigerant temperature can be lowered and the closing operation of the on-off valve can be promptly and reliably performed.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing an open state of an example of an on-off valve of the air conditioner.

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

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

FIG. 5 is a time chart showing an example of operation control in a conventional air conditioner.

[Explanation of symbols]

1 ... Compressor, 2 ... Four-way switching valve, 3 ... Outdoor heat exchanger, 4 ...
Expansion valve, 5 ... Indoor heat exchanger, 5a ... First indoor heat exchanger,
5b ... 2nd indoor heat exchanger, 6a-6f ... Pipe line, 7 ... Outdoor fan, 8 ... Indoor fan, 10 ... Open / close valve, 11 ... Capillary tube (pressure reducing mechanism), 12 ... First passage, 13 ... Second
Passage 14 ... Internal flow passage, 15 ... Valve seat, 16 ... Valve body, 17 ...
Bias spring, 18 ... Shape memory spring, 20 ... Control means,
T ₁ ... First predetermined time, T ₂ ... Second predetermined time.

Claims (2)

[Claims] 1. A compressor (1), a four-way switching valve (2), an outdoor heat exchanger (3), an expansion valve (4), a first indoor heat exchanger (5a) and a second.
The indoor heat exchanger (5b) is sequentially connected by pipelines (6a to 6f), and the on-off valve (10) is provided between the first and second indoor heat exchangers (5a, 5b).
And the pressure reducing means (11) are connected in parallel to each other, and
(10) is opened to operate both indoor heat exchangers (5a, 5b) as an evaporator or a condenser for cooling and heating operations, while the on-off valve (10) is closed to open the first indoor heat exchanger.
In the air conditioner for performing dehumidifying operation by using (5a) as a condenser and the second indoor heat exchanger (5b) as an evaporator, the opening / closing valve (10) includes the first indoor heat exchanger ( 5a) connected to the first passage (12) and the second indoor heat exchanger (5
a second passage (13) connected to b) and an internal passage (14) having a valve seat (15) and connecting the passages (12, 13) to each other, the first passage (12) The valve body that opens and closes the valve seat (15) on the side
(16) is reciprocally arranged so that the valve body (16) is biased in the valve closing direction by the bias spring (17) and in the valve opening direction by the shape memory spring (18), Memory spring
(18) expands in contact with the circulating refrigerant during cooling operation,
While the valve body (16) is moved away from the valve seat (15), the valve body (16) contracts by contacting with a refrigerant having a temperature lower than that of the refrigerant flowing during the cooling operation, so that the valve body (16) contacts the valve seat (15). In addition, in order to shift to the dehumidifying operation, the on-off valve (10)
During the cooling operation to close the valve, the first predetermined time (T ₁ )
The compressor (1) is stopped while the indoor fan (8) is operating for a certain period of time, and then the indoor fan is operated for the second predetermined time (T ₂ ).
Control means (2) for stopping the compressor (8) and operating the compressor (1)
0) is provided. 2. The air conditioner according to claim 1, wherein the control means (20) controls to gradually reduce the opening degree of the expansion valve (4) within the second predetermined time (T ₂ ).