JP2003121019A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air conditioner enabling efficient operation according to operation modes such as heating, cooling, and defrosting operation. SOLUTION: A refrigerating cycle comprises a refrigerant flow passage passing through a compressor 1, an indoor heat exchanger 5, and an outdoor heat exchanger 3. A plurality of passages passing through the outdoor heat exchanger 3, namely a first passage from an inlet side to an outlet side of the outdoor heat exchanger 3, a second passage from the inlet side to a second intermediate passage 13 of the outdoor heat exchanger 3, and a third passage from a first intermediate passage 12 to the outlet side of the outdoor heat exchanger 3, are formed. A switching means is provided for selecting one passage among the plurality of passages depending on operation modes and switching.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an air conditioner that enables efficient operation according to an operation mode such as heating operation, cooling operation or defrosting operation. It is about.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are refrigerant circuit diagrams showing a conventional heat pump air conditioner. FIG. 3 shows a case where a heat exchange path, which is a refrigerant flow path in an outdoor heat exchanger, is a single path. FIG. 4 shows the case where there are a plurality of heat exchange paths. The air conditioner includes a compressor 1 having a capacity control function, a switching valve 2, an outdoor heat exchanger 3, an expansion valve 4 and an indoor heat exchanger 5, and these are sequentially connected by piping to form a refrigeration cycle. ing.

The refrigerant discharged from the compressor 1 is transferred to the switching valve 2
The direction can be switched by this, and by this, it is possible to switch to either the heating operation cycle or the cooling operation cycle. In the figure, the solid arrow indicates the cooling medium flow direction, and the broken line arrow indicates the refrigerant flow direction during heating.

During the cooling operation, the high-temperature high-pressure refrigerant gas compressed by the compressor 1 passes through the switching valve 2 and the outdoor heat exchanger 3
The heat is exchanged with the outside air blown by the outdoor fan 6 while passing through the heat exchange passage to radiate and condense. The condensed refrigerant is decompressed by the throttle controlled by the expansion valve 4, introduced into the indoor heat exchanger 5, and absorbs heat by exchanging heat with the indoor air blown by the indoor fan 7 while passing through the heat exchange passage. -Evaporated and returned to the compressor 1 through the switching valve 2.

Next, the operation during the heating operation will be described. During the heating operation, the high-temperature and high-pressure refrigerant gas compressed by the compressor 1 radiates heat in the indoor heat exchanger 5 through the switching valve 2 and is condensed, and is decompressed by the expansion valve 4 at the throttle controlled according to the refrigerant flow rate. The heat is absorbed by the outdoor heat exchanger 3, evaporated, and returned to the compressor 1 through the switching valve 2.

The outdoor heat exchanger 3 is frosted during the heating operation. This frost is detected by a frost detector or the like, the refrigeration cycle is switched to the cooling operation cycle, and the outdoor heat exchanger 3 is used as a condenser and the indoor heat exchanger 5 is used as an evaporator. To the outdoor heat exchanger 3 for defrosting.

[0007]

The conventional heat pump air conditioner is constructed as described above, and the outdoor heat exchanger through which the refrigerant flows even when the compressor 1 is in capacity control operation and the refrigerant flow rate is changed. The volume of the heat exchange passage of 3 is the same,
Even if the outdoor heat exchanger 3 has an appropriate volume when the flow rate of the refrigerant is high, there is a problem that the volume of the outdoor heat exchanger 3 is too large when the flow rate of the refrigerant is low.

Further, as shown in FIG. 4, when the outdoor heat exchanger 3 has a plurality of heat exchange paths connected in parallel, each heat is used when the outdoor heat exchanger 3 is used as an evaporator during heating operation. The length of the exchange path is shortened, the pressure loss of evaporation pressure is reduced, and the heating performance is improved.

However, when the outdoor heat exchanger 3 is used as a condenser during the cooling operation, the condensing pressure is lowered, so that the condensing performance is deteriorated, which may lower the cooling performance. That is, having a plurality of heat exchange paths connected in parallel is suitable for heating operation, but is not necessarily suitable for cooling operation.

Further, since the cooling operation cycle is performed during the defrosting operation, it is necessary to stop the heating operation, and the longer the defrosting operation is, the longer the heating operation stop time is, resulting in a problem that the heating capacity is lowered.

Therefore, it is an object of the present invention to provide an air conditioner which enables efficient operation according to an operation mode such as heating operation, cooling operation or defrosting operation.

[0012]

In order to achieve the above object, an air conditioner according to the present invention is an outdoor air conditioner in a refrigeration cycle provided with a refrigerant flow path through a compressor, an indoor heat exchanger and an outdoor heat exchanger. A plurality of paths that pass through the heat exchanger are formed, and a switching means that switches so as to select one of the plurality of paths according to an operating state is provided.

Regarding the specific constitution of the plurality of passages, when the number of heat exchange passages is single, an intermediate inlet and an intermediate outlet are provided at an intermediate position of the heat exchange passage through which the refrigerant flows from the inlet side to the outlet side of the outdoor heat exchanger. And a second intermediate flow channel that flows from the intermediate outlet on the outlet side of the outdoor heat exchanger is branched from the first intermediate flow channel that flows to the intermediate inlet on the inlet side of the outdoor heat exchanger. Are joined together, and the plurality of paths passing through the outdoor heat exchanger have a first flow path from the inlet side to the outlet side of the outdoor heat exchanger.
It is possible to adopt a configuration in which the above-mentioned route, the second route that flows from the inlet side of the outdoor heat exchanger to the intermediate outlet, and the third route that flows from the intermediate inlet to the outlet side.

In the above configuration, when the flow rate of the refrigerant is large as in the normal heating operation or the cooling operation, the first path having a large volume of the heat exchange path is selected and the rotation speed of the compressor becomes low. When the flow rate of the refrigerant is low, the heating operation or the cooling operation can be efficiently performed by selecting the second path or the third path.

That is, in the outdoor heat exchanger, when heat is exchanged between the refrigerant and the outside air, the heat exchange rate is better when there is a certain temperature difference between the two. Therefore, when the number of rotations of the compressor is low and the flow rate of the refrigerant is small, the capacity of the heat exchange path is reduced and heat is exchanged within the limited capacity to perform efficient heating operation or cooling operation. be able to.

The air conditioner according to the present invention may be either one of a cooling operation and a heating operation,
The refrigeration cycle may be provided with a switching valve for switching the refrigeration cycle to either the cooling operation cycle or the heating operation cycle, thereby enabling both the heating operation and the cooling operation.

A defrosting operation is required in the case of an air conditioner capable of performing both heating operation and cooling operation.
In this case, instead of defrosting the entire heat exchange path, first
Select the second route to partially defrost, then the third
It is possible to adopt a configuration that defrosts by selecting the route of. By partially defrosting the heat exchange path in this way, it becomes possible to concentrate a large amount of thermal energy and apply it to the heat exchange path, and it is possible to shorten the defrost time and improve the heating performance. It becomes possible.

When the outdoor heat exchanger has a plurality of heat exchange paths, the specific configuration of the plurality of paths is such that the inlet side and the outlet side of each heat exchange path are connected in parallel and each heat exchange path is connected. A connecting path connected in series is provided, and the plurality of paths include a first path through which the refrigerant flows in series through the plurality of heat exchange paths, a second path through which the refrigerant flows in parallel through the plurality of heat exchange paths, and a plurality of It is possible to employ a configuration in which only the one of the heat exchange paths is used as the third path.

According to the above construction, during the heating operation, when the number of revolutions of the compressor is high and the flow rate of the refrigerant is large, the second
By selecting the path of and the plurality of heat exchange paths,
The length of the heat exchange path per book is shortened, the pressure loss of the evaporation pressure is reduced, and the heating performance is improved. Further, when the rotation speed of the compressor is low and the refrigerant flow rate is low, the capacity of the heat exchange path is reduced by selecting the third path, so that the heating operation can be efficiently performed as described above. It will be possible.

During the cooling operation, when the number of rotations of the compressor is high and the flow rate of the refrigerant is large, the first path is selected and the plurality of heat exchange paths are used as one long flow path connected in series. It is possible to prevent the condensing pressure from decreasing by increasing the flow velocity of, so that it is possible to prevent the condensing performance and hence the cooling performance from decreasing. When the rotation speed of the compressor is low, by selecting the third path,
It becomes possible to efficiently perform the cooling operation.

Further, the air conditioner according to the present invention may perform either one of the cooling operation and the heating operation, and as described above, by providing the switching valve, both the heating operation and the cooling operation can be performed. It may be one that enables driving. In the case of an air conditioner capable of performing both heating operation and cooling operation, the third route is selected during the defrosting operation, and first, one heat exchange path is defrosted, and then another heat is removed. A configuration that defrosts the exchange path can be adopted. By performing defrosting for each heat exchange path in this manner, a large amount of heat energy can be concentrated and applied to one heat exchange path, the defrosting time can be shortened, and the heating performance can be improved. It becomes possible to improve.

As described above, a plurality of paths are formed through the outdoor heat exchanger, and one of the plurality of paths is formed depending on the operating condition.
Efficient driving is possible by selecting one of the routes. At this time, as switching means for switching to select one path, an opening / closing valve may be provided in each path to control opening / closing of each opening / closing valve.

The switching means may be controlled by the control device. A control microcomputer can be used as the control device. In addition, if an operating condition detector that detects the operating condition of the air conditioner is provided and the control device switches the route based on the detection signal of this detector, it is more convenient and more efficient. It is possible to obtain an air conditioner with high performance.

As the operation status detector, for example, a temperature sensor can be provided in the refrigerant flow path on the outlet side of the outdoor heat exchanger during the defrosting operation. In this case, when the refrigerant passes through the heat exchange passage in the frosted state, the refrigerant temperature becomes low, but the temperature of the flowing refrigerant rises due to the end of the defrosting. Therefore, when the temperature detected by the temperature sensor reaches a predetermined temperature, it is determined that the defrosting is completed, and the control device may switch and control the route.

A rotation speed detector for detecting the rotation speed of the compressor may be used as another operation status detector. In this case, the path may be switched and controlled according to the rotation speed of the compressor.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION [First Embodiment] FIG. 1 is a refrigerant circuit diagram of an air conditioner showing a first embodiment of the present invention. In this embodiment, the inside of an outdoor heat exchanger 3 is shown. The case where the heat exchange passage, which is the refrigerant passage, is a single passage will be described. The air conditioner of this embodiment includes a compressor 1, a four-way valve 2 as a switching valve, an outdoor heat exchanger 3, an expansion valve 4 and an indoor heat exchanger 5, which are sequentially connected by a refrigerant pipe. A refrigeration cycle is formed.

The outdoor heat exchanger 3 is provided with an intermediate inlet 12a and an intermediate outlet 13a, and is a single heat exchange passage 3a.
Is provided, an intermediate inlet 12a and an intermediate outlet 13a are provided at an intermediate position of the heat exchange passage 3a, and the inlet-side flow passage 10 is an inlet side of the outdoor heat exchanger 3 during the cooling operation or the defrosting operation. At the intermediate inlet 12a, the first intermediate passage 12 is branched, and at the outlet-side passage 11 of the outdoor heat exchanger, the second intermediate passage 13 flowing from the intermediate outlet 13a is joined. .

Further, the inlet side flow passage 10 and the first intermediate flow passage 1
2 and the second intermediate flow path 13 have solenoid valves 8a, 8b,
8d is provided, and the solenoid valve 8 is provided near the downstream side of the connection point with the second intermediate flow path 13 in the heat exchange path 3a.
c is provided, and these electromagnetic valves constitute switching means.

In the above structure, the solenoid valves 8a and 8c are opened and the solenoid valve 8 is opened during the normal heating operation or the cooling operation.
By closing b and 8d, a first path that flows from the inlet side to the outlet side of the outdoor heat exchanger 3 is formed to allow the refrigerant to flow, and the capacity of the heat exchange path 3a is increased to ensure efficient operation. Try to do it. In this case, the flow of the refrigerant during the heating operation or the cooling operation is the same as in FIG.

When the number of rotations of the compressor 1 is low, the flow rate of the refrigerant is small, and the heat exchange path during the normal operation as described above has a too large capacity. In such a case, by opening the solenoid valves 8a and 8d and closing the solenoid valves 8b and 8c, the refrigerant flows only in a part of the heat exchange passage 3a, that is, from the inlet side of the outdoor heat exchanger 3. By forming the second path that flows to the intermediate outlet 13a and flowing the refrigerant, the capacity of the heat exchange path 3a becomes small and efficient operation becomes possible. In addition, in order to reduce the capacity of the heat exchange passage 3a, in addition to the second passage, the solenoid valves 8b and 8c are opened and 8a and 8d are closed, so that the first passage flowing from the intermediate inlet 12a to the outlet side. You may make it pass the refrigerant | coolant by forming the path | route of 3.

In the present embodiment, in order to select either the first path through which the refrigerant flows through the entire heat exchange path 3a or the second path or the third path through which the refrigerant partially flows,
A rotation speed detector (not shown) for detecting the rotation speed of the compressor is provided, and the control device (not shown) configured by the control microcomputer selects the first path when the compressor 1 has a predetermined rotation speed or more. , The second route or the third route is selectively controlled when the rotational speed is lower than a predetermined number of revolutions.

When the heating operation is performed in the above state, since the outdoor heat exchanger 3 is used as an evaporator, the outdoor heat exchanger 3
Becomes low temperature, and the moisture in the air is condensed and frosted on the outdoor heat exchanger 3. Therefore, in order to remove the frost that has frosted on the outdoor heat exchanger 3, the four-way valve 2 is switched during the heating operation to temporarily perform the cooling operation, and the high-pressure and high-temperature gas refrigerant is caused to flow to the outdoor heat exchanger 3 to perform the outdoor operation. The fan 6 is stopped to defrost.

At this time, in this embodiment, the passage is first switched to the second passage by opening the solenoid valves 8a and 8d and closing the solenoid valves 8b and 8c so that the refrigerant flows, and then the second passage. Finish defrosting the route.

Next, the solenoid valve is switched to the solenoid valve 8b, 8
By opening c and closing 8a and 8d, switching to the third path is made to flow the refrigerant, and defrosting of the third path is performed. In this way, during the defrosting operation, the outdoor heat exchanger 3 is divided into the upstream side and the downstream side to perform defrosting in order,
It is possible to shorten the defrosting time and improve the heating operation performance.

In the present embodiment, in order to determine the operation time of the defrosting operation, the outlet side flow passage 11 is provided with the temperature sensor 9 for measuring the temperature of the refrigerant discharged from the outdoor heat exchanger 3. However, when the temperature of the temperature sensor 9 rises to a predetermined temperature, it is determined that the defrosting has ended, and the control device (not shown) controls the switching of the route.

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention.
FIG. 3 is a refrigerant circuit diagram of the air conditioner showing the embodiment of FIG. The present embodiment is characterized in that the heat exchange paths in the outdoor heat exchanger 3 are a plurality of paths 3a and 3b, and other configurations of the refrigerant cycle and the like are the same as in the first embodiment. ing.

The air conditioner of this embodiment comprises an outdoor heat exchanger 3 having a plurality of heat exchange passages 3a and 3b built therein. The inlet side and the outlet side of each heat exchange path 3a, 3b are connected in parallel to the inlet side flow passage 10 and the outlet side flow passage 11.
That is, the inlet-side flow passage 10 and the outlet-side flow passage 11 of the outdoor heat exchanger 3 are branched into branch passages 10a, 10
b and 11a, 11b are formed, and this branch path 1
0a and the branch path 11a, the heat exchange path 3a, the branch path 1
The heat exchange paths 3b are connected in parallel between 0b and the branch path 11b. Further, a connection path 14 is formed between the heat exchange path 3a and the heat exchange path 3b to connect them in series.

Further, the branch passages 10a, 10b, 11a and the communication passage 14 are provided with solenoid valves 8e, 8f, 8h, respectively, which switch the passages of the refrigerant.

Specifically, during the cooling operation, the solenoid valves 8e and 8g are opened and the solenoid valves 8f and 8h are closed, so that the refrigerant flows through the two heat exchange passages 3a and 3b in series. By forming one path and making the refrigerant flow path one long flow path, the flow velocity of the refrigerant is increased and efficient cooling operation is performed.

Further, in the cooling operation, when the number of rotations of the compressor 1 is low and the flow rate of the refrigerant is small, the capacity of the plurality of heat exchange paths is too large. In such a case, the solenoid valve 8
By opening e and 8h and closing the solenoid valves 8f and 8g to form a third passage through which the refrigerant flows only in one heat exchange passage 3a, the capacity of the heat exchange passage is reduced and the efficiency is reduced. It enables good driving. In order to reduce the capacity of the heat exchange passage, the solenoid valve 8f may be opened and the solenoid valves 8e, 8g and 8h may be closed so that the refrigerant flows only through the other heat exchange passage 3b.

During the heating operation, the flow of the refrigerant is opposite to that during the cooling operation, and the outlet side flow passage 11 is the inlet side and the inlet side flow passage 10 is the outlet side flow passage. In such a situation, by opening the solenoid valves 8e, 8f and 8h and closing the solenoid valve 8g, a second path for the refrigerant to flow in parallel through the two heat exchange paths 3a and 3b is formed, and Reduce the pressure loss of evaporation pressure and perform efficient heating operation.

Further, in the heating operation, when the number of revolutions of the compressor 1 is low and the flow rate of the refrigerant is small, the capacity is too large in the plurality of heat exchange paths as in the cooling operation.
Therefore, in such a case, the solenoid valve 8f is opened, and the solenoid valves 8e, 8g, and 8h are closed to form the third passage through which the refrigerant flows only through one heat exchange passage 3b, and the refrigerant is caused to flow. As a result, the capacity of the heat exchange path is reduced, and efficient operation becomes possible. In order to reduce the capacity of the heat exchange passage, the solenoid valves 8e and 8h may be opened and the solenoid valves 8f and 8g may be closed so that the refrigerant flows only through the other heat exchange passage 3a.

During the defrosting operation, the heat exchange paths 3a, 3
A high temperature and high pressure refrigerant gas does not flow through both b at the same time, but first, the solenoid valves 8e and 8h are opened, and the solenoid valves 8f and 8g are closed, so that the refrigerant flows through only one heat exchange passage 3a. To form defrost.

Next, the solenoid valve is switched, the solenoid valve 8f is opened, and the solenoid valves 8e, 8g, and 8h are closed to form a passage for the refrigerant only in the other heat exchange passage 3b for defrosting. Try to do it. In this way, during the defrosting operation, defrosting is performed for each heat exchange path to shorten the defrosting operation time and improve the heating operation performance.

It should be noted that a rotation speed detector for detecting the rotation speed of the compressor is provided to determine the operation time of the defrosting operation, and a temperature sensor is provided at the outlet side flow passage 11, Also, the first point is that a control device for switching and controlling the path based on the detection signals of these operation status detectors is provided.
It is similar to the embodiment.

The present invention is not limited to the above embodiment, and it goes without saying that many modifications and changes can be made within the scope of the present invention. For example, in the above-described embodiment, a plurality of solenoid valves are used as the switching means, but instead of the solenoid valves, the inlet side flow passage 10 in FIG.
It is also possible to use a three-way valve at the confluence A of the first intermediate flow passage 12 and the confluence B of the outlet flow passage 11 and the second intermediate flow passage 13. Similarly in FIG. 2, the branch portion C,
It is also possible to use a three-way valve for D.

[0047]

As is apparent from the above description, according to the present invention, a plurality of paths passing through the outdoor heat exchanger are formed and one of the plurality of paths is selected according to the operating state. By providing the switching means for switching, efficient operation can be performed according to the operation mode such as heating operation, cooling operation, or defrosting operation.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner showing a first embodiment.

FIG. 2 is a refrigerant circuit diagram of an air conditioner showing a second embodiment.

FIG. 3 is a refrigerant circuit diagram of a conventional heat pump air conditioner.

FIG. 4 is a refrigerant circuit diagram showing another aspect of the conventional heat pump air conditioner.

[Explanation of symbols] 1 compressor 2 four-way valve 3 outdoor heat exchanger 4 expansion valve 5 Indoor heat exchanger 8 solenoid valve 9 Temperature sensor

Claims (10)

[Claims] 1. In a refrigeration cycle including a refrigerant flow path that flows through a compressor, an indoor heat exchanger, and an outdoor heat exchanger, a plurality of paths that pass through the outdoor heat exchanger are formed, and a plurality of paths are formed according to operating conditions. An air conditioner characterized by comprising switching means for switching so as to select one of the paths. 2. An intermediate inlet and an intermediate outlet are provided at an intermediate position of a heat exchange passage through which the refrigerant flows from the inlet side to the outlet side of the outdoor heat exchanger, and the refrigerant passage is provided on the inlet side of the outdoor heat exchanger. The first intermediate flow path flowing to the intermediate inlet is branched,
The second intermediate flow passages flowing from the intermediate outlet are merged at the outlet side of the outdoor heat exchanger, and the plurality of paths passing through the outdoor heat exchanger have a first flow passage from the inlet side to the outlet side of the outdoor heat exchanger. The air conditioner according to claim 1, wherein there are a path, a second path that flows from the inlet side of the outdoor heat exchanger to the intermediate outlet, and a third path that flows from the intermediate inlet to the outlet side. 3. A switching valve for switching the refrigeration cycle to either a cooling operation cycle or a heating operation cycle is provided on the discharge side of the compressor of the refrigeration cycle.
Air conditioner described. 4. A control device for switching and controlling the switching means is provided, and the control device selects the second path during the defrosting operation of the outdoor heat exchanger, and the outdoor heat exchanger during the defrosting operation. The air conditioner according to claim 2 or 3, wherein the air conditioner is switched to the third path based on information obtained from the temperature sensor provided in. 5. A control device for switching control of the switching means is provided, and the control device causes the refrigerant to flow through the entire flow path of the outdoor heat exchanger based on the rotation speed of the compressor during the cooling operation or the heating operation. The air conditioner according to claim 2, 3 or 4, wherein the first path and either the second path or the third path through which the refrigerant partially flows are selected. 6. The outdoor heat exchanger has a plurality of heat exchange passages, and an inlet side and an outlet side of each heat exchange passage are connected in parallel, and a connecting passage connecting each heat exchange passage in series is provided. The plurality of paths is one of a plurality of heat exchange paths, a first path in which the refrigerant flows in series through the plurality of heat exchange paths, a second path in which the refrigerant flows in parallel through the plurality of heat exchange paths, and one of the plurality of heat exchange paths. The air conditioner according to claim 1, wherein the air conditioner is a third path that flows only through the air conditioner. 7. The air conditioner according to claim 6, wherein a switching valve that switches the refrigeration cycle to either a cooling operation cycle or a heating operation cycle is provided on the discharge side of the compressor of the refrigeration cycle. 8. A control device for switching control of the switching means is provided, wherein the control device selects a third path during a defrosting operation, and a temperature sensor provided in an outdoor heat exchanger during the defrosting operation. The air conditioner according to claim 6 or 7, wherein the heat exchanger is switched to another heat exchange path based on the obtained information. 9. A control device for switching and controlling the switching means is provided, and the control device selects one of the second route and the third route based on the rotation speed of the compressor during heating operation. The air conditioner according to claim 6, 7 or 8, which is configured as described above. 10. A control device for switching and controlling the switching means is provided, and the control device selects one of a first route and a third route based on a rotation speed of the compressor during a cooling operation. The air conditioner according to claim 6, 7, 8 or 9.