JP4122349B2 - Refrigeration cycle apparatus and operation method thereof - Google Patents

Description

The present invention relates to a refrigeration cycle apparatus and an operation method thereof.

  As a typical refrigeration cycle device having a refrigeration cycle in which an outdoor heat exchanger, an indoor heat exchanger, a compressor, etc. are connected by piping, the outdoor heat exchanger is condensed by switching the direction of refrigerant flow using a four-way valve or the like. Air that enables both the cooling operation in which the heat exchanger and the indoor heat exchanger function as an evaporator, and the heating operation in which the outdoor heat exchanger functions as a condenser and the indoor heat exchanger as a condenser. A harmony machine is known.

  When heating such an air conditioner, depending on the outdoor air temperature, drain water (defrosted water) generated from an outdoor heat exchanger serving as an evaporator may freeze in the lower part of the heat exchanger. In order to prevent such a situation, a part of the refrigerant pipe connecting the indoor expansion valve and the outdoor expansion valve is arranged as a hot line pipe in the lower part of the outdoor heat exchanger to distribute the high-temperature and high-pressure refrigerant. A refrigeration cycle apparatus incorporating a technique is known (for example, see Patent Document 1).

  According to this air conditioner, the refrigerant flowing in the hot line piping is controlled by controlling the opening of the indoor expansion valve and the outdoor expansion valve so that the hot line piping temperature is always within a predetermined temperature range. Maintaining a gas-liquid two-phase state, frosting and icing in the lower part of the outdoor heat exchanger are suppressed together with hotline piping.

However, in the above conventional refrigeration cycle apparatus, all refrigerants flowing from the indoor expansion valve to the outdoor expansion valve flow into the hot line piping during heating operation, and depending on the outdoor air temperature, frost / icing can be prevented. There is a possibility that heat exceeding the required amount of heat will be radiated to the outdoor air via the hot line piping.
For this reason, excessive heat is radiated to the outdoor air up to heat that can be used as the heating capacity on the indoor side, which causes a problem of reducing the heating capacity.

In addition, when the outdoor air temperature is low in the cooling operation, if the entire area of the outdoor heat exchanger is a condenser, the refrigerant condensing pressure is abnormally lower than normal and the evaporation pressure side is also lower. The refrigeration cycle is balanced. At this time, since the drain water on the indoor heat exchanger surface is frozen, frequent start / stop control of the compressor is performed to avoid this. Therefore, not only the comfort of the air conditioning is lowered, but the reliability of the compressor is significantly lowered.
Therefore, when performing cooling operation with low outside air, there is proposed one that realizes continuous operation of the compressor by arranging a plurality of outdoor heat exchangers having different capacities and adjusting the flow of refrigerant to each. (For example, refer to Patent Document 2).

However, in the refrigeration cycle apparatus described in Patent Literature 2, there is a risk that the refrigerant may stay in the outdoor heat exchanger that is not used during the heating operation. In this case, the operation is continued in a state where the necessary refrigerant circulation amount for forming the refrigeration cycle is insufficient, and the reliability of the refrigeration cycle apparatus is lowered.
JP 09-138008 A Japanese Patent Laid-Open No. 2002-061978

  The present invention has been made in view of the above circumstances, and prevents frosting and icing in the lower part of the outdoor heat exchanger without impairing the hotline function, and the pressure state of the refrigerant in the refrigeration cycle is set to a predetermined level. It is an object of the present invention to provide a refrigeration cycle apparatus capable of maintaining the heating capacity and cooling capacity on the indoor unit side within a range and an operating method thereof.

The present invention employs the following means in order to solve the above problems.
A refrigeration cycle apparatus according to the present invention has at least an indoor heat exchanger, an indoor expansion section, an outdoor expansion section, an outdoor heat exchanger, and a refrigeration cycle in which a refrigerant is circulated by connecting pipes sequentially. A refrigeration cycle apparatus,
Refrigerant piping connecting between the indoor expansion portion and the outdoor expansion portion is branched into a first piping passing through at least a part of the outdoor heat exchanger and a second piping not passing through, A first temperature detection unit that detects the temperature of the first pipe; and a second temperature detection unit that detects an outdoor air temperature; and the first pipe includes the outdoor air temperature and the first pipe temperature. A flow rate control means capable of flow control based on the outdoor air temperature and the temperature of the first pipe when the refrigerant flows from the outdoor expansion portion to the outdoor heat exchanger. A flow mechanism that switches the direction of the flow of the refrigerant flowing through one pipe to one of the direction from the indoor expansion section to the outdoor expansion section and the direction from the outdoor expansion section to the compressor. It is characterized by.

  This refrigeration cycle apparatus can distribute the total circulation amount of the refrigerant through the first pipe and the second pipe at a predetermined ratio. Therefore, at the time of heating operation in which the outdoor heat exchanger is used as an evaporator, the high-temperature and high-pressure refrigerant can be circulated also to the lower part of the outdoor heat exchanger, and the refrigerant flowing from the indoor expansion part to the outdoor expansion part While maintaining a high temperature and high pressure state, it is possible to prevent frost formation and icing in the lower part of the outdoor heat exchanger.

The operation method of the refrigeration cycle apparatus according to the present invention is a refrigeration in which at least an indoor heat exchanger, an indoor expansion unit, an outdoor expansion unit, an outdoor heat exchanger, and a compressor are sequentially connected by piping to circulate refrigerant. A method for operating a refrigeration cycle apparatus having a cycle, comprising: a step of detecting an outdoor air temperature; a first pipe disposed via at least a part of the outdoor heat exchanger; Based on the step of detecting the temperature of the first pipe of the refrigerant pipe branched from the indoor side expansion part and the outdoor side expansion part, and the outdoor air temperature and the temperature of the first pipe , Switching the flow of the refrigerant flowing through the first pipe to either the case of flowing from the indoor side expansion part to the outdoor side expansion part or the case of flowing from the outdoor side expansion part to the compressor . It is characterized by.

The refrigeration cycle apparatus according to the present invention includes a refrigeration cycle in which at least an indoor heat exchanger, an indoor expansion unit, an outdoor expansion unit, an outdoor heat exchanger, and a compressor are connected in order to circulate refrigerant. A refrigerant pipe that pipe-connects between the indoor-side expansion part and the outdoor-side expansion part does not pass through a first pipe that passes through at least a part of the outdoor heat exchanger. two pipes and is branched into a second temperature detector for detecting the outdoor air temperature, the heat exchanger unit for circulating the amount of coolant than the first pipe to the outdoor heat exchanger is disposed, the outdoor air Based on the temperature, at least one of the first pipe and the heat exchanging section is provided with a pipe selection mechanism for circulating the refrigerant in one direction from the discharge side of the compressor toward the outdoor heat exchanger side. It is characterized by.

In addition, the operation method of the refrigeration cycle apparatus according to the present invention is such that at least the indoor heat exchanger, the indoor side expansion unit, the outdoor side expansion unit, the outdoor heat exchanger, and the compressor are sequentially connected by piping to circulate the refrigerant. have a made refrigeration cycle, the refrigerant pipe of pipe connecting the indoor expansion part and the chamber outer expansion portion, a second pipe without passing through the first pipe through at least a portion of said outdoor heat exchanger The method of operating the refrigeration cycle apparatus branched to the step of detecting the outdoor air temperature, and based on the detection result of the outdoor air temperature, is arranged via at least a part of the outdoor heat exchanger From the discharge side of the compressor toward the outdoor heat exchanger side, at least one of the first pipe and the heat exchange unit disposed in the outdoor heat exchanger so that more refrigerant than the first pipe can flow. Distribute the refrigerant in one direction Characterized in that it comprises a step.

  In the operation method of the refrigeration cycle apparatus, when the refrigerant is circulated from the compressor side to the outdoor heat exchanger side, the refrigerant can be circulated in one direction by the pipe selection mechanism by the pipe selection mechanism. . At this time, the refrigerant can be circulated through at least one of the first pipe and the heat exchange unit, and the amount of refrigerant passing through the outdoor heat exchanger can be adjusted to a predetermined amount by the outdoor air temperature. Therefore, for example, when the refrigerant discharged from the compressor is circulated only through the first pipe, the flow rate of the refrigerant heat-exchanged by the outdoor heat exchanger can be minimized, even when the outdoor air temperature is low. The refrigerant can be maintained in a high temperature and high pressure state.

Moreover, the operating method of the refrigeration cycle apparatus according to the present invention is an operating method of the refrigeration cycle, further comprising a step of detecting a discharge pressure of the compressor,
The step of circulating the refrigerant in the one direction causes the refrigerant to flow along with the detection result of the discharge pressure of the compressor.

  ADVANTAGE OF THE INVENTION According to this invention, excessive heat radiation can be suppressed and the heating efficiency can be improved, preventing the function fall of an outdoor heat exchanger at the time of heating operation. In addition, a predetermined high and low pressure can be maintained even during cooling operation with low outside air, and the reliability of the compressor can be ensured and the cooling efficiency can be improved. Furthermore, the refrigerant does not stay in a place that is not used as the refrigeration cycle during operation, and the reliability of the refrigeration cycle can be ensured.

A first reference example will be described with reference to FIG.
An air conditioner (refrigeration cycle apparatus) 1 according to this reference example includes an indoor unit 2 and an outdoor unit 3.
An indoor heat exchanger 5 and an indoor expansion valve (indoor expansion unit) 6 are disposed in the indoor unit 2, and an outdoor expansion valve (outdoor expansion unit) 7, outdoor heat is provided in the outdoor unit 3. An exchanger 8, an accumulator 10, a four-way valve 11, and a compressor 12 are arranged. These are connected to each other by piping, and constitute a refrigeration cycle in which refrigerant is circulated.

The refrigerant pipe 13 that pipe-connects between the indoor side expansion valve 6 and the outdoor side expansion valve 7 is the hot line pipe 13A and the bypass pipe 13B. The first branch 13a and the outdoor side expansion valve on the indoor side expansion valve 6 side. Between the second branch 13b on the 7 side, a hot line pipe (first pipe) 13A passing through the lower part of the outdoor heat exchanger 8 and a bypass pipe (second pipe not passing through the lower part of the outdoor heat exchanger 8) Piping) and 13B. The refrigerant pipe 13 is designed in advance so that a predetermined refrigerant circulation amount can be branched into both at a predetermined ratio.
The outdoor heat exchanger 8 has two refrigerant flow paths therein for the purpose of using the heat exchanger, and includes a hot line pipe 13A and a heat exchange portion 8A through which more refrigerant flows. ing.

Next, the operation method of the air conditioner 1 according to this reference example will be described in the case of performing a heating operation, and the actions and effects at that time.
The high-temperature and high-pressure refrigerant discharged from the compressor 12 moves from the outdoor unit 3 to the indoor unit 2 via the four-way valve 11 and flows to the indoor heat exchanger 5, and is decompressed and expanded by the indoor side expansion valve 6. Enters the machine 3 and flows through the refrigerant pipe 13. At this time, the refrigerant flows through the first branch 13a to both the hot line pipe 13A and the bypass pipe 13B at a predetermined ratio, and the refrigerant flowing through the hot line pipe 13A passes through the lower part of the outdoor heat exchanger 8.

At this time, heat is radiated from the refrigerant flowing in the hot line piping 13 </ b> A to the lower part of the outdoor heat exchanger 8.
The refrigerant that has flowed through the hot line piping 13A is merged with the refrigerant that flows through the bypass piping 13B at the second branch 13b, and the refrigerant that bypasses the hot line piping 13A also flows into the bypass piping 13B and passes through the outdoor expansion valve 7. In the heat exchanger 8A of the outdoor heat exchanger 8, heat is exchanged with outdoor air as an evaporator.

According to the air conditioner 1, the refrigerant that maintains the temperature and pressure state of the refrigerant from the indoor expansion valve 6 toward the outdoor expansion valve 7 is circulated through the bypass line 13B while the refrigerant flowing through the hotline pipe 13A is used outdoors. It is possible to prevent frosting and icing in the lower part of the heat exchanger 8.
Therefore, during heating operation, excessive heat radiation to the outdoor air can be suppressed without impairing the hot line function, and heating efficiency can be improved.

Next, a second reference example will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to the 1st reference example mentioned above, and description is abbreviate | omitted.
The difference between the second reference example and the first reference example is that the air conditioner 20 according to this reference example has a hot line piping 13A that serves as an inlet side of the refrigerant to the lower part of the outdoor heat exchanger 8 during heating operation. A hot line piping temperature detection device (first temperature detection unit) 21 for detecting the temperature of the outdoor air, an outdoor air temperature detection device (second temperature detection unit) 22 for detecting the outdoor air temperature, the hot line piping temperature detection device 21 and the outside air A hot line circuit electromagnetic valve (flow rate adjusting means) 23 capable of flow rate control based on the temperature detection device 22 is provided.
The hot line circuit solenoid valve 23 is disposed in the hot line piping 13A on the refrigerant inlet side to the outdoor heat exchanger 8 during heating operation, and is controlled to be opened and closed by a flow rate control device 25.

An operation method during heating by the air conditioner 20 will be described.
This operation method includes a step (S01) of detecting the outdoor air temperature by the outdoor temperature detection device 22, a step (S02) of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21, and the outdoor air. A step (S03) of adjusting the refrigerant flow rate in the hot line piping 13A by opening / closing the hot line circuit electromagnetic valve 23 based on the temperature and the temperature of the hot line piping 13A.

Since the hot line circuit electromagnetic valve 23 is closed when the heating operation is started, the refrigerant flows through the bypass pipe 13B from the indoor expansion valve 6 toward the outdoor expansion valve 7.
After the operation is started, the hot line circuit solenoid valve 23 is opened. Then, as a step of detecting the outdoor air temperature by the outdoor air temperature detection device 22 (S01), the outdoor air temperature detection device 22 detects the outdoor air temperature (TA). Further, as a step (S02) of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21, the hot line piping temperature detection device 21 detects the temperature (Tr) of the hot line piping 13A.

Here, TA is compared with a predetermined temperature α set higher than the freezing point, and when TA <α degrees, there is a risk of frosting or icing in the lower part of the outdoor heat exchanger 8. A step (S03) of adjusting the refrigerant flow rate in the inside is performed, and the hot line circuit electromagnetic valve 23 is opened by the flow rate control device 25.
At this time, a part of the refrigerant flowing in the refrigerant pipe 13 also flows into the hot line pipe 13 </ b> A and passes through the outdoor heat exchanger 8. At this time, the lower part of the outdoor heat exchanger 8 is heated by the refrigerant. Then, the refrigerant again merges with the refrigerant in the bypass pipe 13 </ b> B and flows to the outdoor expansion valve 7.

The above process is repeated, and when TA ≧ α degrees, TA and Tr are compared. When Tr> TA, the hot line circuit electromagnetic valve 23 is closed by the flow control device 25.
At this time, the flow of the refrigerant in the hot line piping 13A stops, the refrigerant flows in the bypass piping 13B, and suppresses excessive heat radiation from the lower portion of the outdoor heat exchanger 8.

On the other hand, when Tr ≦ TA, the hot line circuit electromagnetic valve 23 is opened. At this time, the refrigerant flows in the hot line piping 13A, but since the outdoor air temperature is higher than the temperature of the hot line piping 13A, heat is not released to the outdoor air.
Thus, the heating operation is performed while repeating these steps.

According to this air conditioner 20 and its operating method, the same effect as in the first reference example can be obtained. However, based on the relationship between the temperature of the hot line pipe 13A and the outdoor air temperature, the hot line circuit electromagnetic By opening and closing the valve 23, it is possible to cause the refrigerant to flow through the hot line piping 13A as necessary. Therefore, it is possible to control the amount of refrigerant passing through the hot line piping 13A by using the temperature condition during the heating operation and efficiently use the hot line function, and suppress the heat radiation to the lower portion of the outdoor heat exchanger 8 more than necessary. And the heating performance on the indoor unit side can be maintained.

Next, a third reference example will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to the other reference example mentioned above, and description is abbreviate | omitted.
The difference between the third reference example and the second reference example is that the air conditioner according to the present reference example includes a flow rate adjustment valve instead of the hot line circuit electromagnetic valve 23.
The opening of the flow rate adjusting valve is variable by the flow rate control device 25.

An operation method during heating by the air conditioner will be described.
This operating method includes a step (S11) of detecting the outdoor air temperature by the outdoor temperature detection device 22, a step (S12) of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21, and the outdoor air. A step (S13) of adjusting the flow rate of the refrigerant in the hot line piping 13A by adjusting the opening of the flow rate adjusting valve based on the temperature and the temperature of the hot line piping 13A.

At the start of the heating operation, the flow rate solenoid valve is fully closed, so that the refrigerant flows through the bypass pipe 13B from the indoor expansion valve 6 toward the outdoor expansion valve 7.
After starting operation, the opening of the flow rate adjustment valve is fully opened. Then, as a step (S11) of detecting the outdoor air temperature with the outside air temperature detection device 22 and a step (S12) of detecting the temperature of the hot line piping 13A with the hot line piping temperature detection device 21, a first reference example is provided. Similarly, the outdoor air temperature (TA) and the temperature (Tr) of the hot line piping 13A are detected.

Here, when TA is compared with a predetermined temperature α set higher than the freezing point, and TA <α degrees, the outdoor heat exchanger 8 may be frosted or iced. Is adjusted to adjust the refrigerant flow rate in the hot line piping 13A (S13), and the flow rate control device 25 fully opens the flow rate adjustment valve.
At this time, a part of the refrigerant flowing in the refrigerant pipe 13 also flows into the hot line pipe 13A and passes through the lower part of the outdoor heat exchanger 8. At this time, the lower part of the outdoor heat exchanger 8 is heated by the refrigerant. Then, the refrigerant again merges with the refrigerant in the bypass pipe 13 </ b> B and flows to the outdoor expansion valve 7.

The above process is repeated, and when TA ≧ α degrees, TA and Tr are compared. When Tr> TA, the flow rate control device 25 decreases the opening of the flow rate adjustment valve by a certain amount.
At this time, the flow of the refrigerant in the hot line piping 13A is reduced, and the refrigerant is prevented from being radiated excessively from the lower part of the outdoor heat exchanger 8.

  On the other hand, when Tr = TA, the opening degree of the flow rate adjustment valve is maintained at the current state, and when Tr <TA, the opening degree of the flow rate adjustment valve is increased by a certain amount. At this time, the refrigerant flows in the hot line piping 13A, but since the outdoor air temperature is equal to the temperature of the hot line piping 13A, or the outdoor air temperature is higher, heat is not released to the outdoor air. Thus, the heating operation is performed while repeating these steps.

According to this air conditioner and its operating method, the same effect as in the second reference example can be obtained. In particular, since the flow rate of the refrigerant passing through the hot line piping 13A is more finely controlled in that the opening degree of the valve can be adjusted, the hot line function can be used more efficiently.

Next, a first embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to the reference example mentioned above, and description is abbreviate | omitted.
The difference between the first embodiment and the second reference example is that, in addition to the configuration of the air conditioner 20 according to the second reference example , the air conditioner 40 according to this embodiment includes a hot line pipe 13A. Based on the temperature and the outdoor air temperature, it is provided with a circulation mechanism 41 for diverting at least a part of the refrigerant to the hot line pipe 13A when the refrigerant is circulated from the outdoor expansion valve 7 to the outdoor heat exchanger 8. Is a point.

  The circulation mechanism 41 includes a first bypass pipe 42 and a second bypass pipe 43 that connect the heat exchange unit 8A and the hot line pipe 13A at the refrigerant inlet / outlet in the outdoor heat exchanger 8, and the first bypass pipe 42 and the hot line pipe. The first check valve 45 disposed between the connecting portion 44A to 13A and the connecting portion 44B (second branch 13b) between the hot line piping 13A and the bypass piping 13B, and the first bypass piping 42. A second check valve 46 and an evaporator electromagnetic valve 47 disposed on the second bypass pipe 43 are provided.

The first bypass pipe 42 is arranged by connecting the hot line pipe 13A and the heat exchange part 8A on the outdoor expansion valve 7 side, and is connected to the heat exchange part 8A by a connection part 44C. The second bypass pipe 43 is arranged by connecting the hot line pipe 13A and the heat exchange part 8A on the compressor 12 side, and is connected to the hot line pipe 13A at the connection part 44D from the heat exchange part 8A. It is connected by the connection part 44E.
The first check valve 45 allows only the flow from the connection portion 44A to the connection portion 44B, and the second check valve 46 allows the refrigerant from the outdoor expansion valve 7 to enter the outdoor heat exchanger 8. Only the flow toward the hot line piping 13A in front is allowed.
The evaporator solenoid valve 47 is also controlled to open and close by the flow control device 25.

An operation method during heating by the air conditioner 40 will be described.
This operating method includes a step (S21) of detecting the outdoor air temperature by the outdoor air temperature detection device 22, a step of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21 (S22), and a hot line. Based on the step (S23) in which the refrigerant flow direction in the pipe 13A is the same as that in the outdoor heat exchanger 8, the hot line circuit solenoid valve 23 is opened and closed based on the outdoor air temperature and the temperature of the hot line pipe 13A. And a step (S24) of adjusting the refrigerant flow rate in the hot line piping 13A.

  First, the heating operation is started, the hot line circuit electromagnetic valve 23 is opened, and the evaporator electromagnetic valve 47 is closed. Then, similarly to the second embodiment, the step of detecting the outdoor air temperature by the outdoor temperature detection device 22 (S21) and the step of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21 (S22). The outdoor air temperature detection device 22 detects the outdoor air temperature (TA), and the hot line piping temperature detection device 21 detects the temperature (Tr) of the hot line piping 13A.

Here, when β <TA <α degrees (α is a predetermined temperature set higher than the freezing point and β is a predetermined temperature set lower than the freezing point), frost and icing are formed on the lower part of the outdoor heat exchanger 8. Therefore, a step (S23) of adjusting the refrigerant flow rate in the hot line piping 13A is performed, and only the hot line circuit electromagnetic valve 23 is opened by the flow rate control device 25.
At this time, a part of the refrigerant flowing in the refrigerant pipe 13 flows into the hot line pipe 13A, and the first check valve 45 and the second check valve 46 cause the outdoor expansion valve 7 to move from the indoor expansion valve 6 side. Pass the outdoor heat exchanger 8 lower part only in the direction. Then, the lower part of the outdoor heat exchanger 8 is heated by the refrigerant, and again merges with the refrigerant in the bypass pipe 13 </ b> B and flows to the outdoor expansion valve 7.

When the above process is repeated and TA ≦ β degrees, the step of adjusting the refrigerant flow rate in the hot line piping 13A (S24) is performed to close the hot line circuit electromagnetic valve 23 and open the evaporator electromagnetic valve 47. .
At this time, part of the refrigerant that has passed through the outdoor expansion valve 7 flows from the first bypass pipe 42 through the hot line pipe 13 </ b> A to the second bypass pipe 43. As a result, the hot line piping 13A exhibits a function as an evaporator.

  The above process is further repeated, and when Tr> TA, both the hot line circuit solenoid valve 23 and the evaporator solenoid valve 47 are closed according to the step (S24). When Tr ≦ TA, the hot line circuit solenoid valve 23 is opened and the evaporator solenoid valve 47 is closed. As a result, the refrigerant flowing in the hot line piping 13A flows from the indoor expansion valve 6 side to the outdoor expansion valve 7 side, and heat dissipation to the outdoor air is suppressed.

  According to this air conditioner 40 and its operating method, during heating operation, the refrigerant flows into the hot line piping 13A to suppress frost formation and icing in the lower part of the outdoor heat exchanger 8, and the hot line circuit solenoid valve The open / close control of 23 can suppress heat radiation more than necessary to the outdoor air and maintain the heating performance of the indoor unit. Further, when it is difficult for frost formation or icing to occur on the outdoor heat exchanger 8, the hot line is controlled by the first check valve 45 and the second check valve 46 by controlling the opening and closing together with the electromagnetic valve 47 for the evaporator. The flow direction of the refrigerant in the pipe 13A can be the same direction as the outdoor heat exchanger 8, the hot line pipe 13A can have the same function as an evaporator as the outdoor heat exchanger 8, and the outdoor heat exchange The capacity of the vessel can be increased.

Next, a second embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to 1st Embodiment mentioned above and another reference example, and description is abbreviate | omitted.
The difference between the second embodiment and the first embodiment is that, in the air conditioner according to the present embodiment, a flow rate adjustment valve similar to the third reference example is provided instead of the hotline circuit electromagnetic valve 23. This is the point.
An operation method during heating by the air conditioner will be described.

  As shown in FIG. 7, this operation method includes a step (S31) of detecting the outdoor air temperature with the outdoor air temperature detection device 22, and a step of detecting the temperature of the hot line piping 13A with the hot line piping temperature detection device 21. (S32), a flow rate adjusting valve based on the step (S33) in which the flow direction of the refrigerant in the hot line pipe 13A is the same as that in the outdoor heat exchanger 8, the outdoor air temperature, and the hot line pipe 13A. A step (S34) of adjusting the flow rate of the refrigerant to adjust the refrigerant flow rate in the hot line piping 13A.

  First, heating operation is started, the opening degree of the flow rate adjustment valve is fully opened, and the evaporator electromagnetic valve 47 is closed. Then, as in the fourth embodiment, the step of detecting the outdoor air temperature by the outdoor air temperature detection device 22 (S31) and the step of detecting the temperature of the hot line piping 13A by the hot line piping temperature detection device 21 ( S32) is performed to detect the outdoor air temperature (TA) and the temperature (Tr) of the hot line piping 13A.

Here, when β <TA <α degrees, the outdoor heat exchanger 8 may be frosted or icing, so the step of adjusting the refrigerant flow rate in the hot line piping 13A (S33) is performed. Then, the flow control valve 25 is fully opened by the flow control device 25.
At this time, a part of the refrigerant flowing in the refrigerant pipe 13 flows into the hot line pipe 13A as in the first embodiment, and is only outdoor in the direction from the indoor expansion valve 6 to the outdoor expansion valve 7. Pass through heat exchanger 8. And the outdoor heat exchanger 8 is heated with a refrigerant | coolant, merges with the refrigerant | coolant in the bypass piping 13B again, and flows into the outdoor side expansion valve 7. FIG.

When the above process is repeated and TA ≦ β degrees, the step of adjusting the refrigerant flow rate in the hot line piping 13A (S44) is performed, the flow rate adjustment valve is fully closed, and the evaporator electromagnetic valve 47 is opened.
At this time, a part of the refrigerant that has passed through the outdoor expansion valve 7 flows from the first bypass pipe 42 through the hot line pipe 13A to the second bypass pipe 43, and the hot line pipe 13A functions as an evaporator. Will be demonstrated.

When the above process is further repeated and TA ≧ β and Tr> TA are satisfied, the opening of the flow rate adjusting valve is decreased and the evaporator electromagnetic valve 47 is closed according to the step (S34). When Tr = TA, the opening degree of the flow rate adjustment valve is maintained, and the evaporator solenoid valve 47 is closed.
When Tr <TA, the opening of the flow rate adjustment valve is increased, and the refrigerant flowing in the hot line piping 13A flows from the indoor expansion valve 6 side to the outdoor expansion valve 7 side. , Heat dissipation to outdoor air is suppressed.
According to this air conditioner, the same effects as those of the first embodiment can be obtained. In addition, since the flow rate of the refrigerant amount is controlled more finely in that the opening degree of the valve can be adjusted, the hot line function can be used more efficiently.

Next, a third embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to other embodiment mentioned above and another reference example, and description is abbreviate | omitted.
The difference between the third embodiment and the first embodiment is that the air conditioner according to this embodiment is shown in FIG. 8 instead of the circulation mechanism 41 in the air conditioner 40 according to the first embodiment . When the machine 60 includes a pipe selection mechanism 61 that circulates the refrigerant in one direction from the discharge side of the compressor 12 toward the outdoor heat exchanger 8 side in at least one of the hot line pipe 13A and the heat exchange unit 8A. This is the point.

  The pipe selection mechanism 61 is configured to replace the first open / close valve 63 (solenoid valve) disposed in the pipe 62 connecting the four-way valve 11 and the heat exchange unit 8A and the second bypass pipe 43 with the first open / close valve 11 and the first open / close valve 43. A third bypass pipe 65 connecting the connecting portion 44F and the connecting portion 44D arranged between the valve 63, a third check valve 66 arranged on the third bypass pipe 65, and the hot line circuit electromagnetic valve 23; And a fourth check valve 67 arranged instead of the above.

The third check valve 66 is arranged in a direction in which the flow of the refrigerant in the third bypass pipe 65 is circulated only in one direction from the connection portion 44F to the connection portion 44D. The flow is arranged in a direction in which the flow is circulated only in one direction from the first branch 13a to the connecting portion 44D.
The opening / closing of the first opening / closing valve 63 is controlled by the flow rate control device 69 together with the opening degree of the outdoor expansion valve 7.
Note that the air conditioner 60 is not provided with the first bypass pipe 42 and the hot line pipe temperature detection device 21.

Next, the operation method by the air conditioner 60 will be described.
When performing the heating operation, the outdoor expansion valve 7 is controlled to a predetermined opening degree, and the first on-off valve 63 is always opened.
At this time, the refrigerant is circulated in the same manner as the air conditioner 1 in the first reference example .
That is, the refrigerant that has reached the first branch 13a is branched into the hot line pipe 13A and the bypass pipe 13B.

The refrigerant branched to the hot line pipe 13A and passing through the fourth check valve 67 flows through the lower part of the outdoor heat exchanger 8 instead of the direction of the third bypass pipe 65 by the third check valve 66, and the second branch. At 13b, the refrigerant again flows through the bypass pipe 13B.
The merged refrigerant flows through the outdoor expansion valve 7 through the heat exchanger 8A of the outdoor heat exchanger 8, passes through the first on-off valve 63, and reaches the four-way valve 11.
Thereby, the refrigerant can achieve the same effect as the air conditioner 1 in the first reference example .

On the other hand, as shown in FIG. 9, the operation method for the cooling operation is based on the step (S41) of detecting the outdoor air temperature by the outdoor air temperature detector 22 and the detection result of the outdoor air temperature 13A. Or the entire outdoor heat exchanger 8 is provided with a step of circulating the refrigerant in one direction from the discharge side of the compressor 12 toward the outdoor heat exchanger 8 (S42).
Here, the step (S41) of detecting the outdoor air temperature is the same as the content in the other embodiments and other reference examples .
The step of circulating the refrigerant (S42) further includes a step of flowing the refrigerant only through the hot line pipe 13A (S42A) and a step of flowing the refrigerant through the outdoor heat exchanger 8 (S42B).

First, the cooling operation is started. At this time, the outdoor expansion valve 7 is controlled to a predetermined opening, and the first on-off valve 63 is opened to drive the refrigeration cycle.
Then, the process (S41) which detects outdoor air temperature is implemented, and outdoor air temperature (TA) is detected.

Here, in the case of TA <α (condition 1), the process proceeds to a step (S42A) of flowing the refrigerant only through the hotline pipe 13A.
That is, the outdoor expansion valve 7 is fully closed and the first on-off valve 63 is closed. At this time, the refrigerant discharged from the compressor 12 passes through the four-way valve 11, passes through the third check valve 66 from the connection portion 44 </ b> F, flows into the hot line piping 13 </ b> A, reaches the bypass piping 13 </ b> B, and expands indoors. It is distributed to the valve 6. On the other hand, since the outdoor expansion valve 7 and the first on-off valve 63 are closed, the refrigerant does not flow through the heat exchange unit 8A.

  In this way, only the hot line piping 13A functions as a condenser, and a predetermined range of operating pressure (high pressure and low pressure) can be maintained even in a low outside air state.

On the other hand, the step of detecting the outdoor air temperature (S41) is performed again to detect the outdoor air temperature (TA). When TA <α, the step of flowing the refrigerant only to the hot line pipe 13A (S42A) ) Is further repeated.
Then, when TA ≧ α (condition 2) is satisfied, or when TA ≧ α from the beginning, the process proceeds to the step of flowing the refrigerant through the entire outdoor heat exchanger 8 (S42B).

That is, the outdoor expansion valve 7 is opened to a predetermined opening, and the first on-off valve 63 is opened. At this time, the refrigerant discharged from the compressor 12 passes through the four-way valve 11, passes through the first opening / closing valve 63 from the connection portion 44F, and is circulated to the heat exchange portion 8A. At the same time, the refrigerant flows from the connection portion 44F through the third check valve 66 in the direction of the third bypass pipe 65, and the refrigerant also flows through the hot line pipe 13A.
Therefore, in the outdoor heat exchanger 8, both the heat exchange unit 8A and the hot line piping 13A function as a condenser to perform heat exchange.
Thus, the refrigerant condensed in the outdoor heat exchanger 8 reaches the bypass piping 13B from the outdoor expansion valve 7 and flows to the indoor expansion valve 6. Table 1 shows a list of statuses of the outdoor expansion valve 7 and the first on-off valve 63 in each of the above steps.

  According to this air conditioner 60 and its operating method, the amount of refrigerant flowing through the outdoor heat exchanger 8 can be adjusted to two predetermined amounts by the pipe selection mechanism 61. Therefore, when the refrigerant discharged from the compressor 12 is circulated only through the hot line pipe 13A, the flow rate of the refrigerant passing through the outdoor heat exchanger 8 can be minimized. Accordingly, the function of the outdoor heat exchanger 8 as a condenser can be provided only to the hot line pipe 13A to suppress the heat exchange capacity, and the refrigerant maintained in a predetermined high temperature and high pressure state is circulated to the indoor unit 2. be able to.

  As a result, drain water freezing on the surface of the indoor heat exchanger 5 can be prevented, and the compressor 12 can be operated continuously. Therefore, the cooling operation at a predetermined temperature can be performed, and the compressor 12 Durability can be increased.

Next, a fourth embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to other embodiment mentioned above and another reference example, and description is abbreviate | omitted.
The difference between the fourth embodiment and the third embodiment is that the pipe selection mechanism 71 of the air conditioner 70 according to this embodiment is arranged near the compressor 12 as shown in FIG. A discharge pressure detecting device 72 for detecting the discharge pressure of the machine 12, and a second on-off valve 73 (solenoid valve) arranged instead of the first check valve 45 arranged in the air conditioner 40 according to the first embodiment. ).
The discharge pressure detection device 72 is controlled by a flow rate control device 74 together with other valves.

A method for operating the air conditioner 70 will be described.
In the heating operation, the outdoor expansion valve 7 is controlled to a predetermined opening and the first on-off valve 63 and the second on-off valve 73 are always opened.
Thereby, there can exist an effect | action and effect similar to the air conditioner 60 which concerns on 3rd Embodiment .

As shown in FIG. 11, the operation method for the cooling operation includes a step (S51) of detecting the outdoor air temperature by the outdoor air temperature detection device 22, and a discharge pressure detection device 72 detecting the discharge pressure of the compressor 12. The hot line pipe 13A based on the detection result of the step (S52), the step (S53) of not allowing the refrigerant to flow through any of the hot line pipe 13A and the heat exchange unit 8A, and the outdoor air temperature and the discharge pressure of the compressor 12. Or a step (S54) for circulating the refrigerant in one direction from the discharge side of the compressor 12 toward the outdoor heat exchanger 8 side.
As in the sixth embodiment, the step of circulating the refrigerant (S54) includes a step of flowing the refrigerant only to the hot line pipe 13A (S54A) and a step of flowing the refrigerant through the entire outdoor heat exchanger 8 (S54B). I have.

First, when the air conditioner 70 is driven, a step (S51) for detecting the outdoor air temperature and a step (S52) for detecting the discharge pressure are performed to perform the outdoor air temperature (TA) and the discharge pressure (Pd) of the compressor 12. ) Is detected.
Here, when TA <α and Pd <γ (γ is a predetermined pressure value) (condition 3), the step of not allowing the refrigerant to flow through either the hot line pipe 13A or the heat exchange unit 8A (S53) Migrate to
That is, the outdoor expansion valve 7 is fully closed, and the first on-off valve 63 and the second on-off valve 73 are closed. At this time, even if the refrigerant is about to be discharged from the compressor 12, it does not circulate in the refrigeration cycle, so that the discharge pressure increases early.

In this state, the process of detecting the discharge pressure (S52) is performed again to detect the discharge pressure (Pd).
At this time, when the discharge pressure is γ ≦ Pd <δ (δ is a predetermined pressure value larger than γ) (condition 4), the process proceeds to the step of flowing the refrigerant only in the hot line piping 13A (S54A), The cooling operation is continued by performing the same processing as the step (S42A) of flowing the refrigerant only through the hot line piping 13A in the sixth embodiment.

In this case, as in the sixth embodiment, the refrigerant discharged from the compressor 12 is circulated through the hot line piping 13A, and no refrigerant flows through the heat exchange unit 8A.
Therefore, only the hot line piping 13A functions as a condenser.
In this case, a smaller amount of refrigerant is circulated through the outdoor heat exchanger 8 than when the refrigerant is circulated through the heat exchange unit 8A, so that the refrigerant discharged from the compressor 12 is maintained in a high pressure state.

Next, the step of detecting the outdoor air temperature (S51) and the step of detecting the discharge pressure (S52) are performed again to detect the outdoor air temperature (TA) and the discharge pressure (Pd). If TA ≧ α and Pd ≧ δ (condition 5), the process proceeds to the step of flowing the refrigerant through the outdoor heat exchanger 8 (S54B).
That is, the outdoor expansion valve 7 is opened to a predetermined opening, the first on-off valve 63 is opened, and the second on-off valve 73 is opened. At this time, the refrigerant discharged from the compressor 12 is circulated through the entire outdoor heat exchanger 8 for heat exchange, as in the step of flowing the refrigerant through the entire outdoor heat exchanger 8 according to the sixth embodiment (S42B). The Table 2 shows a list of statuses of the outdoor expansion valve 7, the first on-off valve 63, and the second on-off valve 73 in each of the above steps.

According to the air conditioner 70 and the operation method thereof, since there is a step (S53) in which the refrigerant is not circulated in any of the hot line piping 13A and the heat exchange unit 8A during the cooling operation, the discharge of the compressor 12 is performed. The pressure can be increased early, and the rise time of the entire refrigeration cycle immediately after the start of operation can be shortened.
Moreover, since the discharge pressure of the compressor 12 is directly detected by the discharge pressure detection device 72 and the refrigerant flow is controlled in accordance with the detection result of the outdoor air temperature, only the outdoor air temperature is detected to control the operation. Compared to the case, more detailed condensation pressure control can be performed, and the high-pressure state of the refrigerant can be maintained at a high pressure.

Next, a fifth embodiment will be described with reference to FIGS.
In addition, the same code | symbol is attached | subjected to the component similar to other embodiment mentioned above and another reference example, and description is abbreviate | omitted.
The difference between the fifth embodiment and the fourth embodiment is that the air according to this embodiment is used instead of the second on-off valve 73 according to the pipe selection mechanism 71 of the air conditioner 70 according to the fourth embodiment. The pipe selection mechanism 81 of the conditioner 80 is provided with a flow rate adjustment valve 82 that can adjust the refrigerant flow rate steplessly. The flow rate adjusting valve 82 is controlled by a flow rate control device 83 together with other valves.

A method for operating the air conditioner 80 will be described.
In the heating operation, the outdoor expansion valve 7 is controlled to a predetermined opening, the first opening / closing valve 63 is opened, and the flow rate adjustment valve 82 is fully opened.
Thereby, there can exist an effect | action and effect similar to the air conditioner 70 which concerns on 4th Embodiment .

As shown in FIG. 13, the operation method for the cooling operation includes a step (S61) of detecting the outdoor air temperature by the outdoor air temperature detecting device 22, and a discharge pressure detecting device 72 detecting the discharge pressure of the compressor 12. Step (S62) and the detection result of the outdoor air temperature and the discharge pressure of the compressor 12, the hot line piping 13A or the entire outdoor heat exchanger 8 is changed from the discharge side of the compressor 12 to the outdoor heat exchanger 8 side. And a step of circulating the refrigerant in one direction (S63).
The step of circulating the refrigerant (S63) further includes a step of flowing the refrigerant only to the hot line piping 13A (S63A), a step of gradually increasing the flow rate of the refrigerant flowing only to the hot line piping 13A (S63B), and an outdoor heat exchanger. 8 (S63C).

First, when the cooling operation is started, the outdoor expansion valve 7 and the flow rate adjustment valve 82 are respectively controlled to predetermined opening degrees, and the first on-off valve 63 is opened to circulate the refrigerant. Then, the step of detecting the outdoor air temperature (S61) and the step of detecting the discharge pressure (S62) are performed to detect the outdoor air temperature (TA) and the discharge pressure (Pd) of the compressor 12.
Here, when TA <α and Pd <γ (condition 3), the process proceeds to the step of flowing the refrigerant only through the hotline pipe 13A (S63A).

That is, the outdoor expansion valve 7 is fully closed, the first on-off valve 63 is closed, and the flow rate adjustment valve 82 is closed by a predetermined amount until a predetermined opening degree is reached. At this time, the pressure of the refrigerant discharged from the compressor 12 and flowing through the hot line piping 13A increases. On the other hand, since the outdoor expansion valve 7 is fully closed and the first on-off valve 63 is closed, the refrigerant does not flow into the heat exchanging portion 8A.
Therefore, only the hot line piping 13A functions as a condenser, and the refrigerant discharged from the compressor 12 is brought into a high pressure state earlier.

  When the discharge pressure is detected again (S62) and the discharge pressure (Pd) of the compressor 12 is detected, the discharge pressure is γ ≦ Pd <ε (ε is a predetermined value between γ and δ). In the case of (pressure) (condition 6), the cooling operation is continued with the opening degree of the flow rate adjustment valve 82 being maintained.

When the discharge pressure is detected by repeating the step of detecting the discharge pressure (S62) and the discharge pressure (Pd) of the compressor 12 is detected, if the discharge pressure becomes ε ≦ Pd <δ (condition 7), the hot line piping 13A It moves to the process (S63B) which increases the refrigerant | coolant flow volume which flows only into only gradually.
That is, the state of the outdoor expansion valve 7 and the first on-off valve 63 is left as it is, and the flow rate adjustment valve 82 is opened by a certain amount so as to have a predetermined opening.
In this case, since the amount of refrigerant flowing through the hot line piping 13A increases, the pressure increase rate of the discharge pressure of the compressor 12 is relaxed.

Then, the step of detecting the outdoor air temperature (S61) and the step of detecting the discharge pressure (S62) are performed to detect the outdoor air temperature (TA) and the discharge pressure (Pd) of the compressor 12. At this time, if TA ≧ α and Pd ≧ δ (condition 5), the process proceeds to the step of flowing the refrigerant through the entire outdoor heat exchanger 8 (S63C).
That is, the outdoor expansion valve 7 is opened to a predetermined opening, the first on-off valve 63 is opened, and the flow rate adjustment valve 82 is fully opened. At this time, similarly to the other embodiments described above, the refrigerant discharged from the compressor 12 is circulated throughout the outdoor heat exchanger 8. Table 3 shows a list of statuses of the outdoor expansion valve 7, the first on-off valve 63, and the flow rate adjustment valve 82 in each of the above steps.

According to this air conditioner 80 and its operation method, instead of the second on-off valve 73 in the air conditioner 70 according to the fourth embodiment , the flow rate adjustment valve 82 capable of adjusting the flow rate is arranged. The discharge pressure of the compressor 12 can be controlled more stably than when simply performing the opening / closing control. Therefore, the refrigerant pressure in the refrigeration cycle can be leveled more suitably, and more stable air conditioning can be performed.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the third to fifth embodiments , in the operation method of the air conditioner during the cooling operation, the outdoor heat exchanger 8 from the discharge side of the compressor 12 is connected to the hot line piping 13A or the outdoor heat exchanger 8 as a whole. Although the process of circulating the refrigerant in one direction toward the side is provided, depending on the operating conditions, control may be performed to distribute the refrigerant only to the heat exchange unit 8A of the outdoor heat exchanger 8.

It is a block diagram which shows the air conditioner which concerns on a 1st reference example . It is a block diagram which shows the air conditioner which concerns on a 2nd reference example and a 3rd reference example . It is a flowchart explaining the driving | operation method at the time of the heating operation of the air conditioner which concerns on the 2nd reference example of this invention. It is a flowchart explaining the driving | operation method at the time of the heating operation of the air conditioner which concerns on the 3rd reference example of this invention. It is a block diagram which shows the air conditioner which concerns on the 1st and 2nd embodiment of this invention. It is a flowchart explaining the driving | operation method at the time of the heating operation of the air conditioner which concerns on the 1st Embodiment of this invention. It is a flowchart explaining the driving | operation method at the time of the heating operation of the air conditioner which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the air conditioner which concerns on the 3rd Embodiment of this invention. It is a flowchart explaining the driving | operation method at the time of the cooling operation of the air conditioner which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the air conditioner which concerns on the 4th Embodiment of this invention. It is a flowchart explaining the driving | operation method at the time of the cooling operation of the air conditioner which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the air conditioner which concerns on the 5th Embodiment of this invention. It is a flowchart explaining the driving | operation method at the time of the cooling operation of the air conditioner which concerns on the 5th Embodiment of this invention.

Explanation of symbols

1, 20, 40, 60, 70, 80 Air conditioner (refrigeration cycle apparatus)
5 Indoor Heat Exchanger 6 Indoor Expansion Valve 7 Outdoor Expansion Valve 8 Outdoor Heat Exchanger 8A Heat Exchanger 12 Compressor 13 Refrigerant Pipe 13A Hotline Pipe (First Pipe)
13B Bypass piping (second piping)
21 Hotline piping temperature detector (first temperature detector)
22 Outside air temperature detector (second temperature detector)
23 Hot line circuit solenoid valve (flow rate adjusting means)
41 Distribution mechanism 61, 71, 81 Pipe selection mechanism

Claims (5)

At least an indoor heat exchanger, an indoor side expansion section, an outdoor expansion section, an outdoor heat exchanger, and a refrigeration cycle apparatus having a refrigeration cycle in which a compressor is sequentially connected by piping to circulate a refrigerant,
Refrigerant piping connecting between the indoor expansion portion and the outdoor expansion portion is branched into a first piping passing through at least a part of the outdoor heat exchanger and a second piping not passing through, A first temperature detection unit that detects the temperature of the first pipe; and a second temperature detection unit that detects an outdoor air temperature; and the first pipe includes the outdoor air temperature and the first pipe temperature. A flow rate control means capable of flow control based on the outdoor air temperature and the temperature of the first pipe when the refrigerant flows from the outdoor expansion portion to the outdoor heat exchanger. A flow mechanism that switches the direction of the flow of the refrigerant flowing through one pipe to one of the direction from the indoor expansion section to the outdoor expansion section and the direction from the outdoor expansion section to the compressor. refrigerating cycle apparatus characterized by being An operation method of a refrigeration cycle apparatus having at least an indoor heat exchanger, an indoor expansion section, an outdoor expansion section, an outdoor heat exchanger, and a refrigeration cycle in which a compressor is circulated by connecting pipes sequentially. ,
Detecting the outdoor air temperature;
Refrigerant piping that branches between the first piping arranged via at least a part of the outdoor heat exchanger and the second piping not via the piping to connect the indoor expansion portion and the outdoor expansion portion. Detecting the temperature of the first pipe of
Based on the outdoor air temperature and the temperature of the first pipe, when the flow of the refrigerant flowing through the first pipe flows from the indoor expansion section to the outdoor expansion section, from the outdoor expansion section to the compressor A method of operating the refrigeration cycle apparatus, the method comprising: At least indoor heat exchanger, indoor side expansion section, outdoor expansion section, outdoor heat exchanger, and compressor
Is a refrigeration cycle apparatus having a refrigeration cycle in which refrigerant is circulated by sequentially connecting pipes.
And
Refrigerant piping connecting between the indoor expansion portion and the outdoor expansion portion is branched into a first piping passing through at least a part of the outdoor heat exchanger and a second piping not passing through, and the outdoor piping and a second temperature detection unit, the heat exchanger unit for circulating the amount of coolant than the first pipe to the outdoor heat exchanger is disposed to detect the air temperature, based on the outdoor air temperature, wherein the first pipe and A refrigeration cycle apparatus, wherein at least one of the heat exchange units includes a pipe selection mechanism for circulating the refrigerant in one direction from the discharge side of the compressor toward the outdoor heat exchanger side. At least the indoor heat exchanger, the indoor expansion part, the outdoor expansion part, an outdoor heat exchanger, and the compressor are sequentially pipe connection have a refrigerating cycle composed by circulating refrigerant, wherein said indoor expansion unit This is a method for operating a refrigeration cycle apparatus in which a refrigerant pipe that connects a pipe to an outdoor expansion section is branched into a first pipe that passes through at least a part of the outdoor heat exchanger and a second pipe that does not pass through the refrigerant pipe. And
Detecting the outdoor air temperature;
Based on the detection result of the outdoor air temperature, the first pipe arranged via at least a part of the outdoor heat exchanger and the outdoor heat exchanger are arranged so that more refrigerant can flow through the first pipe. And a step of circulating the refrigerant in one direction from the discharge side of the compressor toward the outdoor heat exchanger side in at least one of the heat exchange sections. . Further comprising the step of detecting the discharge pressure of the compressor,
The operating method of the refrigeration cycle apparatus according to claim 4 , wherein the step of circulating the refrigerant in the one direction causes the refrigerant to circulate together with a detection result of a discharge pressure of the compressor.