JP2524382B2 - Air conditioner - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of an air conditioner that performs cooling / heating operation using a refrigeration cycle circuit.

[Conventional technology]

Conventionally, this type of air conditioner has a structure as schematically shown in FIG. Briefly describing this, reference numeral 1 in the figure indicates a compressor, 2 indicates a four-way switching valve, 3 indicates an outdoor heat exchanger,
Reference numerals 4 and 5 denote first and second expansion devices that function as expansion mechanisms during cooling operation and heating operation, respectively, 6 is an indoor heat exchanger, and 7 is an accumulator. A refrigeration cycle circuit is configured. In addition, 8 and 9 are the indoor side and the outdoor side and outdoor side air blowers, respectively, which blow air to the outdoor heat exchangers 6 and 3, and 4a and 4b are the first pressure reducing device (capillary) that constitutes the first expansion device 4. Tube) and a first check valve provided in a circuit that bypasses the tube, 5a and 5b in a second pressure reducing device (capillary tube) that constitutes the second expansion device 5 and a circuit that bypasses this. It is a second check valve provided.

In the air conditioner having such a configuration, during cooling operation (the flow of the refrigerant is indicated by a thick solid arrow in the figure), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2. , Outdoor heat exchanger 3 and outdoor blower 9
The gas refrigerant is condensed and liquefied by exchanging heat with the outdoor air blown by. Then, the gas passes through the first check valve 4b in the bypass circuit on the side of the first expansion device 4 and is introduced to the second pressure reducing device 5a constituting the second expansion device 5, where the pressure is reduced and the low-temperature low-pressure Liquid refrigerant. After that, the liquid refrigerant enters the indoor heat exchanger 6, exchanges heat with the indoor air blown by the indoor blower 8, cools the indoor air, and the liquid refrigerant is vaporized and gasified by the four-way switching valve. 2. A refrigerating cycle for cooling is constituted by returning to the compressor 1 through the accumulator 7, and thereafter the refrigerant is circulated in the refrigerating cycle path described above while repeating liquefaction and vaporization.

On the other hand, during the heating operation (the flow of the refrigerant is indicated by a thin solid arrow in the figure), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2 switched to the heating side, and the room The gas enters the inner heat exchanger 6, exchanges heat with the indoor air blown by the indoor blower 8 to heat the indoor air, and thereby the gas refrigerant is condensed and liquefied. Then, this liquid refrigerant passes through the second check valve 5b in the circuit that bypasses the second expansion device 5, is guided to the first pressure reducing device 4a that constitutes the first expansion device 4, and is decompressed. , Becomes a low-temperature low-pressure liquid refrigerant. Then, the liquid refrigerant enters the outdoor heat exchanger 3, exchanges heat with the outdoor air blown by the outdoor blower 9, collects heat from the outdoor air to cool the outdoor air, and thereby the liquid refrigerant is vaporized and gasified, Four-way switching valve 2,
After passing through the accumulator 7 and returning to the compressor 1, a refrigeration cycle for heating is constituted.

Further, if such a heating operation is continuously performed, for example, when the outdoor air temperature is low, frost is formed on the outdoor heat exchanger 3. When such frost increases, the heat exchange efficiency deteriorates, and the amount of heat taken from the outdoor air decreases, so that the heating capacity of the air conditioner significantly decreases. Therefore, in such a case, it is necessary to perform defrosting.

During such a defrost operation (the flow of the refrigerant is indicated by a dashed arrow in the figure), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is switched from the heating side to the cooling side by the four-way switching valve 2 And enters the outdoor heat exchanger 3. Here, the outdoor blower 9 is stopped. Then, the frost that has formed on the surface of the outdoor heat exchanger 3 is melted by the high-temperature gas refrigerant, and the refrigerant is condensed and liquefied, and the first check valve 4b that bypasses the first expansion device 4 is operated. As described above, the refrigerant is decompressed by the second decompression device 5a constituting the second expansion device 5, becomes a low-temperature low-pressure liquid refrigerant, enters the indoor heat exchanger 6, and then is compressed through the four-way switching valve 2 and the accumulator 7. The refrigeration cycle operation of returning to the machine 1 was performed.

[Problems to be Solved by the Invention]

By the way, when the low-temperature and low-pressure liquid refrigerant is introduced into the indoor-side heat exchanger 6 during the above-described defrost operation during the heating operation, some problems occur. That is, the indoor blower 8 arranged to face the indoor heat exchanger 6
Is normally performing a light breeze operation or is stopped during this defrost operation. Then, for example, when the breeze operation is performed, the low-temperature low-pressure liquid refrigerant is heat-exchanged with the room air, the room air is cooled, and the liquid refrigerant is vaporized and gasified, and passes through the four-way switching valve 2 and the accumulator 7 to be compressed. Return to machine 1. Therefore, in such a case, the cold air is blown out to the indoor side, which causes a problem that the air conditioning effect is significantly reduced.

When the indoor blower 8 is stopped, the low-temperature low-pressure liquid refrigerant cannot collect heat, and the refrigerant enters the accumulator 7 and returns to the compressor 1 as a liquid, so that the compressor 1 is liquid-compressed,
It sometimes caused compressor trouble.

Further, according to the above-mentioned conventional device, there is a drawback that the high pressure is low especially at the time of defrosting, the low pressure is also lowered, the compressor 1 cannot fully exhibit its capability, and the defrosting time is long. In addition, since the four-way switching valve 2 is switched to the cooling side during the heating operation and the defrost operation is performed, there is a problem that heat loss occurs during the switching.

The present invention has been made in view of the above-mentioned circumstances, and prevents the blowing of cold air into the room during the defrost operation during the heating operation, and performs the defrost operation with the four-way switching valve left on the heating side, thereby reducing the low pressure. An air conditioner that can prevent the liquid from returning to the compressor by increasing the pressure to increase the compression function and also by performing heat exchange between the high temperature and high pressure gas refrigerant from the compressor and the suction side pipe. The purpose is to get.

[Means for solving the problem]

An air conditioner according to the present invention, a compressor, a four-way switching valve that switches the flow of high-temperature high-pressure refrigerant discharged from the compressor, an outdoor heat exchanger including an outdoor blower,
An air conditioner comprising a second expansion device for decompressing a refrigerant during heating and an indoor heat exchanger equipped with an indoor blower, which are sequentially connected by a refrigerant pipe to form a refrigerant circuit. A valve, the three-way switching valve is connected between the compressor and the four-way switching valve by the compressor discharge-side refrigerant pipe, and the outdoor heat exchanger and the second heat exchanger are connected via the three-way switching valve. A fourth bypass circuit, which is bypassed and connected between the pipes connecting the expansion devices, is provided, and the three-way switching valve is provided on the four-way switching valve side during heating operation and on the fourth bypass circuit side during defrost operation. During the switching and defrosting operation, the four-way switching valve is operated in the heating mode.

Further, a first bypass circuit is provided, which is connected in a bypass from the middle of the discharge side refrigerant pipe from the compressor to the three-way switching valve and between the pipe connecting the outdoor heat exchanger and the second expansion device, and The first bypass circuit is provided with a suction heat exchanger section for exchanging heat with the suction side refrigerant pipe of the compressor and a pressure reducing device for depressurizing the refrigerant in the middle of the piping.

Further, the refrigerant circuit is provided with a first expansion device that reduces the pressure of the refrigerant during cooling, and the first expansion device and the second expansion device have second and third bypass circuits that bypass the respective decompression devices. Along with these, the second and third bypass circuits are provided with check valves that allow the flow of the refrigerant only to the outdoor side and the indoor side heat exchanger side, respectively, and the discharge side refrigerant device of the compressor and the four-way switching valve. A three-way switching valve connected between the four-way switching valve and the discharge side refrigerant pipe to the four-way switching valve side during the heating operation and the cooling operation and to the fourth bypass circuit side during the defrost operation, and the four-way switching valve during the defrost operation. The three-way switching valve is switched while the switching valve is in the heating operation state.

In addition, an auxiliary heat source is installed near the indoor heat exchanger.

The inner diameter of the fourth bypass circuit is smaller than the inner diameter of the discharge side refrigerant pipe of the compressor.

Further, a fifth bypass circuit including an auxiliary depressurizing means connected by bypass from the fourth bypass circuit to the suction side refrigerant pipe side of the compressor is provided, and the fifth bypass circuit is provided with the fifth bypass circuit during the defrost operation. It is configured so as to be opened together with the bypass circuit of No. 4.

In addition, the third bypass valve is provided in the fourth bypass circuit.

[Action]

According to the present invention, when frost is formed on the outdoor heat exchanger during the heating operation, by switching the three-way switching valve while the four-way switching valve is kept in the heating operation, heat generated by the conventional four-way switching valve switching Defrost operation can be performed by preventing loss and blowing cold air into the room. Moreover,
Refrigerant does not flow to the indoor heat exchanger via the four-way switching valve during defrost operation, does not accumulate and accumulate, and there is no shortage of defrost refrigerant flowing to the fourth bypass circuit, enabling quick defrost. Is.

Further, the suction heat exchanger section of the first bypass circuit prevents the refrigerant from returning to the compressor during heating, cooling and defrosting.

Further, the low pressure of the compressor is increased by the fifth bypass circuit, the capacity of the compressor is increased, and the defrost time can be shortened.

〔Example〕

FIG. 1 shows an embodiment of an air conditioner according to the present invention. In FIG. 1, parts that are the same as or correspond to those in FIG. 3 described above are given the same numbers and their explanations are omitted.

Now, according to the present invention, the compressor 1, the four-way switching valve 2, the outdoor heat exchanger 3, the first expansion device 4, the second expansion device 5,
In an air conditioner including a refrigerant circuit in which an indoor heat exchanger 6 and an accumulator 7 are sequentially connected by a refrigerant pipe, the accumulator 7 and the compressor 1 are branched from a discharge side pipe of a compressor 1 and connected. Through the suction heat exchanger 11 configured to exchange heat with the suction side pipe 1a and through the auxiliary capillary tube 12 and connected to the pipe side between the first and second expansion devices 4 and 5 by bypassing. A first bypass pipe 10 is provided. A second bypass circuit 4c provided with a check valve 4b that bypasses the first pressure reducing device 4a and a third bypass valve 5b that bypasses the second pressure reducing device 5a.
And a bypass circuit 5c. Further, the discharge side pipe 1b of the compressor 1 is thinner than the inner diameter of the discharge side pipe 1b which is bypassed and connected to the pipe side between the first and second expansion devices 4 and 5 via the three-way switching valve 13. A fourth bypass circuit 14 having a pipe inner diameter is provided. In such a configuration, the indoor side and outdoor heat exchangers 6, while the four-way switching valve 2 is kept in the heating operation state during the defrost operation,
The blowers 8 and 9 for blowing air to 3 are stopped, and the three-way switching valve 13 is switched to open the fourth bypass circuit 14 so that the defrost operation can be performed.

In the air conditioner having the above-described configuration, during the cooling operation (the refrigerant flow is in the direction indicated by the thick solid line in the figure), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2 to the outside The heat exchanger 3 exchanges heat with the outdoor air blown by the outdoor blower 9, whereby the gas refrigerant is condensed and liquefied. Then, the pressure is reduced by the first pressure reducing device 4a in the first expansion device 4, and becomes a low-temperature low-pressure liquid refrigerant. On the other hand, a part of the high-temperature high-pressure gas refrigerant discharged from the compressor 1 exchanges heat with the low-pressure refrigerant sucked into the compressor 1 in the suction heat exchanger 11 through the first bypass circuit 10 to transfer the sucked refrigerant. It is heated to be completely vaporized, condensed and liquefied by itself, and is decompressed by the auxiliary capillary tube 12 to become a low-temperature low-pressure liquid refrigerant, and the first and second expansion devices.
It joins the pipe between 4 and 5, and the third
Through the bypass circuit 5c of the indoor heat exchanger 6 to exchange heat with the indoor air blown from the indoor blower 8 to cool the indoor air, whereby the liquid refrigerant is vaporized and gasified, and the four-way switching valve 2 Further, a refrigeration cycle circuit is configured that passes through the accumulator 7 and returns to the compressor 1.

Further, during the heating operation (the flow of the refrigerant is in the direction of the arrow indicated by the thin solid line in the figure), the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 2 switched to the heating side to the indoor side. While entering the heat exchanger 6 and exchanging heat with the indoor air blown from the indoor side blower 8 to heat the indoor air,
As a result, the gas refrigerant is condensed and liquefied. Then, the pressure is reduced by the second pressure reducing device 5a in the second expansion device 5,
It becomes a low-temperature low-pressure liquid refrigerant. On the other hand, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is part of the first bypass circuit 10
Through the suction heat exchanger 11 to exchange heat with the low-pressure refrigerant sucked into the compressor 1 to heat and completely vaporize the sucked refrigerant, condense and liquefy itself, and reduce the pressure by the auxiliary capillary tube 12. It becomes a refrigerant and joins the pipe side, and the second bypass circuit 4c in the first expansion device 4
Through the outdoor heat exchanger 3 to exchange heat with the outdoor air blown from the outdoor blower 9 to cool the outdoor air by collecting heat from the outdoor air, and thereby the liquid refrigerant is vaporized and gasified, and the four-way switching is performed. A refrigeration cycle circuit is configured in which the flow returns to the compressor 1 through the valve 2 and the accumulator 7.

Further, during such heating operation, for example, during defrost operation required when the outdoor air temperature is low and frost forms on the outdoor heat exchanger 3 (the flow of the refrigerant is in the direction of the arrow indicated by the broken line in the figure). First, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the three-way switching valve 13 in the state of being switched to the defrost side, and the first and second expansion devices 4,5.
It flows into the piping side through the fourth bypass circuit 14 connected to the piping side between them.

On the other hand, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the first bypass circuit 10 and exchanges heat with the low-pressure refrigerant sucked into the compressor 1 by the suction heat exchanger 11, While heating the suction refrigerant to completely vaporize it,
The condensed liquid itself is decompressed by the auxiliary capillary tube 12 to become a low-temperature low-pressure liquid refrigerant, which is mixed with the high-temperature high-pressure gas refrigerant passing through the fourth bypass circuit 14. Then, the combined gas refrigerants pass through the second bypass circuit 4c in the first expansion device 4 and enter the outdoor heat exchanger 3. At this time, the outdoor blower 9 is stopped. Then, the high-temperature gas refrigerant melts the frost that has frosted on the surface of the outdoor heat exchanger 3 with the high-temperature gas refrigerant, and this refrigerant condenses and liquefies into the accumulator 7 through the four-way switching valve 2 and the compressor 1
Will be returned to.

Therefore, during such defrosting, the defrosting operation can be started without switching the four-way switching valve 2 from the heating side to the cooling side, so that there is no heat loss for switching. Further, since the low-temperature liquid refrigerant does not pass through the indoor side heat exchanger 6, the problem that the cold air is blown out toward the indoor side as in the conventional case is solved. Further, the inner diameter of the pipe forming the fourth bypass circuit 14 is made smaller than that of the discharge side pipe 1b, and pressure loss occurs, the high pressure side pressure of the compressor 1 rises, and the input increases. The capacity of the compressor 1 is increased, and the defrost time can be shortened. Further, since the suction side heat exchanger 11 is configured to perform heat exchange with the suction side pipe 1a for the compressor 1 by the high-temperature and high-pressure gas refrigerant discharged from the compressor 1, a liquid return phenomenon to the compressor 1 is prevented. This makes it possible to prevent compressor trouble.

Here, as shown by 15 in the figure, if an electric heater as an auxiliary heat source is installed so as to face the indoor heat exchanger 6, the refrigerant does not pass through the indoor heat exchanger 6 during the defrost operation. Therefore, the indoor blower 8 can be operated, and there is an advantage that the heating operation can be continued even during the defrost operation.

FIG. 2 shows another embodiment of the air conditioner according to the present invention. In this embodiment, the first and second throttle devices from the discharge side pipe 1b of the compressor 1 in the above-mentioned embodiment are shown. The third check valve 18 is provided in the fourth bypass circuit 14 provided by bypass connection to the pipe between the four and five, and is connected by bypass from the upstream side to the suction side pipe 1a side of the compressor 1. Auxiliary capillary tube 17 as auxiliary decompression means
The fifth bypass circuit 16 having the above is provided.

Then, according to such a configuration, during the cooling operation or the heating operation, the operating state is the same as that of the above-described embodiment,
The following operating conditions occur during defrost operation. That is, during this defrost operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the three-way switching valve 13 to the fourth
After passing through the third check valve 18 by the bypass circuit 14, the flow is introduced into the pipe side between the first and second expansion devices 4 and 5. Further, a part of the high-temperature high-pressure gas refrigerant discharged from the compressor 1 heats and vaporizes the low-pressure refrigerant on the suction side of the compressor 1 by vaporizing the low-pressure refrigerant on the suction side of the compressor 1 as described above by the first bypass circuit 10. The pressure is reduced to form a low-temperature low-pressure liquid refrigerant, which is mixed with the high-temperature high-pressure gas refrigerant from the fourth bypass circuit 14 side, is sent to the outdoor heat exchanger 3 side through the second bypass circuit 4c, and its surface The frost that has been frosted on is melted, and the refrigerant condensed and liquefied by this is sucked into the compressor 1 side through the four-way switching valve 2 and the accumulator 7. Further, the refrigerant in the suction side pipe 1a of the compressor 1 is vaporized by the high-temperature high-pressure gas refrigerant flowing through the first bypass circuit 10 by the suction heat exchanger 11, so that the liquid return to the compressor 1 is returned. The phenomenon can be prevented.

Then, according to the present embodiment, during such a defrost operation, a part of the high-temperature and high-pressure gas refrigerant passing through the fourth bypass circuit 14 is branched to the fifth bypass circuit 16, and the auxiliary capillary tube 17 is provided. Since it flows into the low pressure side (suction side pipe 1a) of the compressor 1 while the flow rate is controlled by, the low pressure pressure rises, the capacity of the compressor 1 increases, and the defrost time can be shortened. It becomes possible.

The present invention is not limited to the structure of the above-described embodiment, and the shape, structure, etc. of each part of the air conditioner can be freely modified or changed as necessary.

〔The invention's effect〕

As described above, according to the air conditioner of the present invention, the three-way switching valve is provided, and the three-way switching valve is connected between the compressor and the four-way switching valve by the compressor discharge side refrigerant pipe, and the three-way switching valve is connected. A fourth bypass connecting between the outdoor heat exchanger and the pipe connecting the second expansion device via the switching valve.
The bypass circuit is provided to switch the three-way switching valve to the four-way switching valve side during the heating operation, to the fourth bypass circuit side during the defrost operation, and the four-way switching valve to the heating operation during the defrost operation. Since the refrigerant does not flow into the indoor heat exchanger via the four-way switching valve and does not condense and accumulate during the defrost operation, the defrost refrigerant flowing to the fourth bypass circuit is insufficient. Without the need for quick defrosting,
It also has the remarkable effect of preventing heat loss and cold air blowout due to the conventional switching of the four-way switching valve.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a refrigeration cycle circuit showing an embodiment of an air conditioner according to the present invention, FIG. 2 is a schematic configuration diagram of a refrigeration cycle circuit showing another embodiment of the present invention, and FIG. It is a schematic block diagram which shows a prior art example. 1 ... Compressor, 1a ... Suction side piping, 1b ... Discharge side piping,
2 ... Four-way switching valve, 3 ... Outdoor heat exchanger, 4,5 ... First and second throttle devices, 4a, 5a ... First and second pressure reducing device (capillary tube), 4b, 5b ... Check valve, 4
c, 5c ...... first and second bypass circuits, 6 ... indoor heat exchanger, 7 ... accumulator, 8,9 ... indoor and outdoor blower, 10 ... first bypass circuit, 11 ...... Suction heat exchanger, 12 …… Auxiliary capillary tube, 13
...... Three-way selector valve, 14 ...... Fourth bypass circuit, 15 ...... Electric heater, 16 ...... Fifth bypass circuit, 17 ...... Auxiliary capillary tube (auxiliary decompression means), 18 ...... Third check valve valve.

Claims (7)

(57) [Claims] 1. A compressor, a four-way switching valve for switching the flow of high-temperature and high-pressure refrigerant discharged from the compressor, an outdoor heat exchanger equipped with an outdoor blower, and a second pressure reducing valve for heating. In the air conditioner having a throttle device and an indoor heat exchanger provided with an indoor blower, which are sequentially connected by a refrigerant pipe to form a refrigerant circuit, a three-way switching valve is provided, and the three-way switching valve is provided. Is connected by the compressor discharge-side refrigerant pipe between the compressor and the four-way switching valve, and the second heat exchanger is connected to the outdoor heat exchanger via the three-way switching valve.
A fourth bypass circuit that bypasses and connects between the pipes that connect the expansion device is provided, and the three-way switching valve is provided on the four-way switching valve side during heating operation.
An air conditioner characterized by switching to the side of the fourth bypass circuit during defrost operation, and during defrost operation with the four-way switching valve kept in heating operation. 2. A first bypass circuit, which is connected by bypassing from the middle of the discharge side refrigerant pipe from the compressor to the three-way switching valve, between the pipe connecting the outdoor heat exchanger and the second expansion device. The first bypass circuit is provided with, in the middle of its piping, a suction heat exchanger section for exchanging heat with the suction side refrigerant piping of the compressor, and a decompression device for decompressing the refrigerant. The air conditioner according to claim 1. 3. A refrigerant circuit is provided with a first expansion device for decompressing the refrigerant during cooling, and the first expansion device and the second expansion device are second and third bypasses bypassing the respective decompression devices. In addition to having a circuit, each of the second and third bypass circuits is provided with a check valve that allows the flow of the refrigerant only to the outdoor side and the indoor side heat exchanger side. A three-way switching valve connected between the four-way switching valve and the discharge-side refrigerant pipe is switched to the four-way switching valve side during the heating operation and the cooling operation, and to the fourth bypass circuit side during the defrost operation, and during the defrost operation. The air conditioner according to claim 2, wherein the three-way switching valve is switched while the four-way switching valve is in a heating operation state. 4. The air conditioner according to claim 1, wherein an auxiliary heat source is installed near the indoor heat exchanger. 5. The pipe inner diameter of the fourth bypass circuit is set to a pipe inner diameter smaller than the inner diameter of the discharge side refrigerant pipe of the compressor, claim 1, claim 2, claim 3 or claim Item 4. The air conditioner according to Item 4. 6. A fifth bypass circuit having auxiliary depressurizing means, which is connected by bypass from the fourth bypass circuit to the suction side refrigerant pipe side of the compressor, is provided, and during defrost operation, this fifth bypass circuit is provided. Is configured to be opened together with the fourth bypass circuit, The air conditioner according to claim 1, claim 2, claim 3, claim 4 or claim 5. 7. The air conditioner according to claim 6, wherein the fourth bypass circuit is provided with a third check valve.