JP5875649B2 - Air conditioner - Google Patents

Description

  The present invention relates to an air conditioner that controls the opening of an expansion valve when a compressor is started.

  As a conventional air conditioner, there is one that controls an initial opening degree of an expansion valve when a compressor is started according to an outside air temperature. For example, when the outside air temperature is high, the initial opening of the expansion valve at the start of the compressor is increased, and when the outside air temperature is low, the initial opening of the expansion valve at the start of the compressor is reduced. (For example, refer to Patent Document 1).

JP-A-4-222341 (page 4-5, FIG. 5)

  In the conventional air conditioner described above, the initial opening degree of the expansion valve at the time of starting the compressor is controlled only by the outside air temperature. For example, in the case of cooling operation, the outside air temperature is determined as the high outside air temperature condition. The initial opening of the expansion valve at the time of starting the compressor is set to a large value under the condition that the room intake temperature is very high and the indoor suction temperature is very high. In this case, the suction pressure is high and the suction gas density is high, that is, the refrigerant circulation amount is large. In addition, since the initial opening degree of the expansion valve is large, it becomes slower to apply the suction superheat (suction superheat), so that the refrigerant returns to the compressor in the liquid state, and the compressor malfunctions due to factors such as liquid compression. May result in a so-called liquid back state.

  Also, for example, in the case of cooling operation, when the outside air temperature is high within the range determined as the low outside air temperature condition and the indoor suction temperature is very low, the expansion at the time of starting the compressor is performed. Set the initial opening of the valve small. In this case, the evaporator may be frozen due to an excessive decrease in the evaporation pressure, or the operation may be stopped intermittently to prevent the evaporator from freezing. Further, since the suction pressure is low and the suction gas density is low, that is, the refrigerant circulation amount is low, the cooling of the compressor is insufficient and the discharge temperature of the compressor is excessively raised, thereby preventing this. For this reason, there was a problem that the operation could be stopped.

  The present invention has been made to solve the above-described problems, and ensures an appropriate operation state from the start-up by using the outside air temperature and the indoor suction temperature at the start of the cooling operation or the start of the heating operation. An air conditioner that can prevent freezing of the exchanger, prevent the compressor discharge temperature from rising excessively, avoid liquid compression, etc., and expand the continuous operation range and improve the reliability of the compressor, etc. The purpose is to provide.

The air conditioner according to the present invention is at least an air conditioner having a refrigerant circuit configured by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger by a refrigerant pipe. An outdoor temperature sensor that is provided on the outdoor heat exchanger side and detects the outdoor air temperature, an indoor temperature sensor that is provided on the indoor heat exchanger side and detects the indoor suction temperature, and expansion when the compressor is started at the start of heating operation Conditions for determining the initial opening of the valve are set as at least conditions 4 and 5, and when the outside air temperature detected by the outside air temperature sensor is lower than a fourth predetermined value or when the outside air temperature is a fourth predetermined temperature. If the outside air temperature is lower than the difference between the indoor intake temperature detected by the indoor temperature sensor and the fifth predetermined value, the condition 5 is satisfied, And controlling the opening of the expansion valve so as to set initial opening degree matter 5, the outside air temperature is higher than a fourth predetermined value, and the temperature and the fifth suction chamber outside air temperature is detected by the indoor temperature sensor And a control device that controls the opening of the expansion valve so that the initial opening is larger than the initial opening in the condition 5, assuming that the condition 4 is satisfied. It is.

  According to the present invention, when the outside air temperature is lower than the fourth predetermined value, or when the outside air temperature is higher than the fourth predetermined value and the outside air temperature is lower than the difference between the indoor suction temperature and the fifth predetermined value, Assuming that condition 5 is satisfied, the opening degree of the expansion valve is controlled so that the initial opening degree set in condition 5 is obtained, and when the outside air temperature is higher than the difference, it is assumed that condition 4 is satisfied, and condition 5 The opening of the expansion valve is controlled so that the initial opening is larger than the initial opening. Thereby, it is possible to secure an appropriate amount of circulating refrigerant when the compressor is started. In addition, when the expansion valve is controlled so that the initial opening degree set in the condition 5 is obtained, the required heating performance can be obtained by adding the degree of subcooling of the refrigerant, and the rising indoor unit The blowing temperature can be made sufficiently high. Furthermore, when the expansion valve is controlled so that the initial opening degree set in the condition 4 is reached, an excessive increase in the discharge temperature can be suppressed by the cooling effect of the compressor by the refrigerant.

It is a refrigerant circuit figure which shows the structure of the air conditioner which concerns on embodiment. It is a flowchart which shows the operation | movement at the time of the cooling operation start of the air conditioner which concerns on embodiment. FIG. 3 is a map diagram in which Condition 1, Condition 2, and Condition 3 in FIG. It is a map figure of the modification which shows Condition 1 and Condition 2 by making a horizontal axis | shaft outside temperature and a vertical axis | shaft indoor indoor temperature. It is a flowchart which shows the operation | movement at the time of the heating operation start of the air conditioner which concerns on embodiment. FIG. 6 is a map diagram showing the condition 4 and the condition 5 in FIG. 5 in a partitioned manner with the horizontal axis as the outside air temperature and the vertical axis as the indoor suction temperature. It is a refrigerant circuit figure of the air conditioner which shows the modification of embodiment.

FIG. 1 is a refrigerant circuit diagram illustrating a configuration of an air conditioner according to an embodiment.
The air conditioner of the present embodiment is configured by sequentially connecting a compressor 1, a four-way valve 7, an outdoor heat exchanger 2, an electronic linear expansion valve 4, an indoor heat exchanger 5, an accumulator 11 and the like through a refrigerant pipe 15. The refrigerant circuit 16 is provided. In addition, the air conditioner controls the actuators 10 such as the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 based on temperature information from a plurality of sensors described later. It has. Note that the control device 10 is configured so that the air temperature sensor 8, the outdoor pipe temperature sensors 13a and 13b, the indoor temperature sensor 9, the indoor pipe temperature sensor 14a, The temperature of each part detected by 14b is read.

  The above-mentioned four-way valve 7 is a valve for switching between a cooling cycle and a heating cycle. When switched to the cooling operation, the outdoor heat exchanger 2 functions as a condenser and the indoor heat exchanger 5 functions as an evaporator. When switched to operation, the outdoor heat exchanger 2 acts as an evaporator and the indoor heat exchanger 5 acts as a condenser. The accumulator 11 separates the liquid phase from the refrigerant sucked into the compressor 1 and stores excess refrigerant in the refrigerant circuit 16.

  On the outdoor heat exchanger 2 side, an outdoor fan 3, an outdoor temperature sensor 8 for detecting the temperature of the outside air, an outdoor pipe temperature sensor 13a for detecting the temperatures of the two-phase flow part and the liquid phase part in the heat exchanger and the pipe, 13b etc. are provided. On the indoor heat exchanger 5 side, an indoor fan 6, an indoor temperature sensor 9 for detecting the indoor suction temperature, an indoor pipe temperature sensor 14a for detecting the temperature of the two-phase flow part and the liquid phase part in the heat exchanger and the pipe, 14b etc. are provided. As each temperature sensor described above, for example, a sensor is used.

  In the air conditioner configured as described above, the flow of the refrigerant during the cooling operation flows as indicated by the solid arrow shown in FIG. The refrigerant is compressed by the compressor 1 to become a high-temperature and high-pressure gas refrigerant, and flows into the outdoor heat exchanger 2 through the four-way valve 7. The gas refrigerant exchanges heat with the outdoor air sent by the outdoor fan 3 in the outdoor heat exchanger 2 (dissipates heat) to become a high-pressure liquid refrigerant. Thereafter, the liquid refrigerant is expanded to a predetermined pressure by the electronic linear expansion valve 4 to become a low-pressure gas-liquid two-phase refrigerant and flows into the indoor heat exchanger 5. The gas-liquid two-phase refrigerant flowing into the indoor heat exchanger 5 exchanges heat (absorbs heat) with the indoor air sent by the indoor blower 6 to become a low-temperature and low-pressure gas refrigerant, and the compressor passes through the four-way valve 7 and the accumulator 11. Return to 1.

  Further, the flow of the refrigerant during the heating operation flows as indicated by the wavy arrow in FIG. The refrigerant is compressed by the compressor 1 as described above to become a high-temperature and high-pressure gas refrigerant, and flows into the indoor heat exchanger 5 via the four-way valve 7. The gas refrigerant exchanges heat (radiates heat) with the indoor air sent by the indoor fan 6 in the indoor heat exchanger 5 to become a high-pressure liquid refrigerant. Thereafter, the liquid refrigerant is expanded to a predetermined pressure by the electronic linear expansion valve 4 to become a low-pressure gas-liquid two-phase refrigerant and flows into the outdoor heat exchanger 2. The gas-liquid two-phase refrigerant that has flowed into the outdoor heat exchanger 2 exchanges heat with the outdoor air sent by the outdoor fan 3 (heat absorption) to become a low-temperature and low-pressure gas refrigerant, and the compressor passes through the four-way valve 7 and the accumulator 11. Return to 1.

Next, the operation at the start of the cooling operation will be described with reference to FIGS.
FIG. 2 is a flowchart showing the operation at the start of cooling operation of the air conditioner according to the embodiment. FIG. 3 is a condition 1, condition 2 and condition 3 in FIG. It is a map figure which divides and shows. Note that Condition 1 and Condition 2 shown in FIG. 3 are divided using T1 (first predetermined value) and Tea = Tca−T2 (second predetermined value) as thresholds, and Condition 2 and Condition 3 are T1 and Teaa. = Tca−T3 (third predetermined value) is used as a threshold value.

  When the control device 10 receives a cooling operation start signal by the user's remote control operation, the control device 10 starts the cooling operation, and then reads the indoor suction temperature Tea detected by the indoor temperature sensor 9. Then, the control device 10 determines whether or not the read indoor suction temperature Tea is lower than the first predetermined value T1 (S1).

When the indoor suction temperature Tea is lower than the first predetermined value T1, for example, at the point A as shown in FIG. 3, the control device 10 sets the condition 1 as the condition 1 is satisfied (S2). The following equation (1) is selected, and a pulse for determining the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is calculated according to the equation (1).
Sj = 220 + C1 × (Fj−C2) (1)
Here, Sj represents the pulse of the opening degree of the electronic linear expansion valve 4, Fj represents the starting frequency of the compressor 1, and C1 and C2 represent constants.

  Thereafter, the control device 10 activates the actuator of the electronic linear expansion valve 4 with the calculated pulse Sj, and opens the electronic linear expansion valve 4 so that the opening degree corresponds to the pulse Sj (S3). In this case, the opening degree (initial opening degree) of the electronic linear expansion valve 4 is larger than the initial opening degree of the electronic linear expansion valve 4 set in the conditions 2 and 3.

  When the electronic linear expansion valve 4 is opened, the control device 10 starts the compressor 1 at a preset starting frequency (S4). Thereafter, the control device 10 enters a normal cooling operation and controls the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 so that the room temperature is set by the remote controller ( S5).

  When it is determined in S1 that the indoor suction temperature Tea is higher than the first predetermined value T1, the control device 10 reads the outside air temperature Tca detected by the outside air temperature sensor 8, and the second outside temperature Tca is read from the outside air temperature Tca. The difference is obtained by subtracting the predetermined value T2, and it is determined whether or not the previously read indoor suction temperature Tea is lower than the difference (S6). When the indoor suction temperature Tea is lower than the difference (Tca−T2), for example, at the point B as shown in FIG. 3, the control device 10 performs the above-described operation assuming that the condition 1 is satisfied (S2). (S3-S5).

Further, when it is determined in S6 that the indoor suction temperature Tea is higher than the difference, the control device 10 subtracts the third predetermined value T3 from the previously read outside air temperature Tca to obtain a difference (Tca−T3). And it is determined whether the indoor suction temperature Tea read in S1 is more than the difference (Tca-T3) (S7). When the indoor suction temperature Tea is lower than the difference, for example, in the case of the point C as shown in FIG. 3, the control device 10 assumes that the condition 2 is satisfied (S8), and the following equation ( 2) is selected, and a pulse for determining the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is calculated according to the equation (2).
Sj = 120 + C1 × (Fj−C2) (2)

  Thereafter, the control device 10 activates the actuator of the electronic linear expansion valve 4 with the calculated pulse Sj, and opens the electronic linear expansion valve 4 so that the opening degree corresponds to the pulse Sj (S9). In this case, the opening degree (initial opening degree) of the electronic linear expansion valve 4 is smaller than the initial opening degree of the electronic linear expansion valve 4 set in the conditions 1 and 3.

  When the electronic linear expansion valve 4 is opened, the control device 10 starts the compressor 1 at a preset starting frequency (S4). Thereafter, the control device 10 enters a normal cooling operation in the same manner as described above, and the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 so that the room temperature is set by the remote controller. Is controlled (S5). The start-up frequency of the compressor 1 is the same as the start-up frequency of the compressor 1 when the opening degree (initial opening degree) of the electronic linear expansion valve 4 is set by satisfying the condition 1.

Further, when the control device 10 determines in S7 that the indoor suction temperature Tea is equal to or higher than the difference (Tca−T3), for example, in the case of the point D as shown in FIG. 3, the condition 3 is satisfied (S10). Then, the following equation (3) set in the condition 3 is selected, and a pulse for determining the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is calculated according to the equation (3).
Sj = 140 + C1 × (Fj−C2) (3)

  Thereafter, the control device 10 activates the actuator of the electronic linear expansion valve 4 with the calculated pulse Sj, and opens the electronic linear expansion valve 4 so that the opening degree corresponds to the pulse Sj (S11). In this case, the opening degree (initial opening degree) of the electronic linear expansion valve 4 is smaller than the initial opening degree of the electronic linear expansion valve 4 set in the condition 1, and the electronic linear expansion valve 4 set in the condition 2 is used. Is slightly larger than the initial opening.

  When the electronic linear expansion valve 4 is opened, the control device 10 starts the compressor 1 at a preset starting frequency (S4). Thereafter, the control device 10 enters a normal cooling operation in the same manner as described above, and the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 so that the room temperature is set by the remote controller. Is controlled (S5). Note that, as described above, the starting frequency of the compressor 1 is the same as the starting frequency of the compressor 1 when the opening degree (initial opening degree) of the electronic linear expansion valve 4 is set by satisfying the condition 1.

As described above, at the start of the cooling operation, when the indoor suction temperature Tea is lower than the first predetermined value T, or the indoor suction temperature Tea is higher than the first predetermined value T, and the indoor suction temperature Tea is equal to the outdoor air temperature Tca. When the difference is smaller than the predetermined value T2 of 2, it is assumed that the condition 1 is satisfied, and the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is set large.
When the determination is made only with the outside air temperature as in the above-described prior art, since the initial opening degree of the electronic linear expansion valve 4 is set small, an appropriate amount of circulating refrigerant cannot be ensured, but in this embodiment, an appropriate circulating refrigerant is used. The amount can be secured. As a result, it is possible to prevent an excessive decrease in the evaporation pressure, and an intermittent operation state in which operation and stop are repeated to prevent freezing of the indoor heat exchanger 5 and to prevent freezing of the indoor heat exchanger 5. Can be avoided, and an excessive increase in the discharge temperature of the compressor 1 can be prevented.

Further, at the start of the cooling operation, when the indoor suction temperature Tea is higher than the difference and the indoor suction temperature Tea is lower than the difference between the outside air temperature Tca and the third predetermined value T3, it is assumed that the condition 2 is satisfied, and the compressor The initial opening degree of the electronic linear expansion valve 4 at the time of starting 1 is set small.
When the determination is made only with the outside air temperature as in the prior art described above, since the initial opening degree of the electronic linear expansion valve 4 is set to be large, there is a possibility of falling into the liquid back state. Even in a high intake gas density state, that is, in a state where the amount of circulating refrigerant is large, it is possible to sufficiently apply the degree of suction superheat (suction superheat), so that the refrigerant returns to the compressor 1 in a liquid state and is compressed by liquid. It is possible to suppress the possibility of falling into a so-called liquid back state that may lead to a failure of the compressor 1 due to factors such as the above.

Further, at the start of the cooling operation, when the indoor suction temperature Tea is equal to or greater than the difference between the outside air temperature Tca and the third predetermined value T3, it is determined that the condition 3 is satisfied, and the initial state of the electronic linear expansion valve 4 set in the condition 1 is satisfied. The opening degree is set to be slightly larger than the initial opening degree of the electronic linear expansion valve 4 set in the condition 2, which is smaller than the opening degree.
When the determination is made only with the outside air temperature as in the above-described prior art, since the initial opening degree of the electronic linear expansion valve 4 is set small, an appropriate amount of circulating refrigerant cannot be ensured, but in this embodiment, an appropriate circulating refrigerant is used. The amount can be secured. Thereby, even if the cooling operation is performed in the server room in winter, the intermittent operation for preventing freezing of the indoor heat exchanger 5 as described above can be prevented.

  In the embodiment, as described above, when the condition 1 is satisfied, the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is set large, and the condition 2 is satisfied. The initial opening degree of the electronic linear expansion valve 4 at the time of starting the compressor 1 is set small, and when the condition 3 is satisfied, it is smaller than the initial opening degree of the electronic linear expansion valve 4 set in the condition 1, Although it is set to be slightly larger than the initial opening degree of the electronic linear expansion valve 4 set in the condition 2, it is not limited to this. For example, as shown in FIG. 4, when the condition 1 is satisfied, the initial opening degree of the electronic linear expansion valve 4 is set large, and when the condition 2 is satisfied, the initial state of the electronic linear expansion valve 4 is set. An air conditioner that sets the opening degree small may be used.

Next, the operation for starting the heating operation will be described with reference to FIGS. 5 and 6.
FIG. 5 is a flowchart showing an operation at the start of heating operation of the air conditioner according to the embodiment, and FIG. 6 is a partition of condition 4 and condition 5 in FIG. 5 where the horizontal axis is the outside air temperature and the vertical axis is the indoor intake temperature. FIG. Note that Condition 4 and Condition 5 shown in FIG. 6 are divided using T4 (fourth predetermined value) and Tea = Tca−T5 (fifth predetermined value) as threshold values.

  When the control device 10 receives the heating operation start signal by the user's remote control operation, the control device 10 starts the heating operation, and then reads the outside air temperature Tea detected by the outside air temperature sensor 8. Then, the control device 10 determines whether or not the read outside temperature Tea is lower than a fourth predetermined value T4 (S21).

When the outside air temperature Tea is lower than the fourth predetermined value T4, for example, at the point E as shown in FIG. 6, the control device 10 sets the condition 5 as the condition 5 being satisfied (S22). The following equation (4) is selected, and a pulse for determining the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is calculated according to the equation (4).
Sj = 157 + C3 × (Fj−C4) (4)
Here, C3 and C4 represent constants.

  Thereafter, the control device 10 activates the actuator of the electronic linear expansion valve 4 with the calculated pulse Sj, and opens the electronic linear expansion valve 4 so that the opening degree corresponds to the pulse Sj (S23). In this case, the opening degree (initial opening degree) of the electronic linear expansion valve 4 is slightly smaller than the initial opening degree of the electronic linear expansion valve 4 set in the condition 4.

  When the electronic linear expansion valve 4 is opened, the control device 10 activates the compressor 1 at the activation frequency (S24). Thereafter, the control device 10 enters a normal heating operation and controls the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 so that the room temperature set by the remote controller is reached ( S25).

  When it is determined in S21 that the outside air temperature Tea is higher than the fourth predetermined value T4, the control device 10 reads the indoor suction temperature Tca detected by the indoor temperature sensor 9 and calculates the fifth predetermined temperature from the indoor suction temperature Tca. A difference is obtained by subtracting the value T5, and it is determined whether or not the previously read outside air temperature Tea is lower than the difference (S26). When the outside air temperature Tea is lower than the difference (Tca−T5), the control device 10 performs the above-described operation (S23 to S25) assuming that the condition 5 is satisfied (S22).

Further, when the controller 10 determines in S26 that the outside air temperature Tea is higher than the difference (Tca−T5), for example, in the case of the point F as shown in FIG. 6, the condition 4 is satisfied (S27). Then, the following equation (5) set in the condition 4 is selected, and a pulse for determining the initial opening degree of the electronic linear expansion valve 4 when the compressor 1 is started is calculated according to the equation (5).
Sj = 167 + C3 × (Fj−C4) (5)

  Thereafter, the control device 10 activates the actuator of the electronic linear expansion valve 4 with the calculated pulse Sj, and opens the electronic linear expansion valve 4 so that the opening degree corresponds to the pulse Sj (S28). In this case, the opening degree (initial opening degree) of the electronic linear expansion valve 4 is slightly larger than the initial opening degree of the electronic linear expansion valve 4 set in the condition 5.

  When the electronic linear expansion valve 4 is opened, the control device 10 activates the compressor 1 at the activation frequency (S24). Thereafter, the control device 10 enters a normal heating operation and controls the compressor 1, the electronic linear expansion valve 4, the outdoor blower 3, and the indoor blower 6 so that the room temperature set by the remote controller is reached ( S25). The starting frequency of the compressor 1 is the same as the starting frequency of the compressor 1 when the opening degree (initial opening degree) of the electronic linear expansion valve 4 is set by satisfying the condition 5.

  As described above, when the heating operation is started, the outside air temperature Tea is lower than the fourth predetermined value T4, or the outside air temperature Tea is higher than the fourth predetermined value T4, and the outside air temperature Tea is equal to the indoor suction temperature Tca and the fifth predetermined value. When the difference from the value T5 is lower, it is assumed that the condition 5 is satisfied, and the initial opening of the electronic linear expansion valve 4 when the compressor 1 is started is set small. That is, when the outside air temperature Tea is high and the indoor suction temperature Tca is very high as indicated by a point G in FIG. 6, the initial opening degree of the electronic linear expansion valve 4 is set to be small. ), The required heating performance can be obtained, and the blowout temperature on the rising indoor heat exchanger 5 side can be sufficiently increased.

  When the outside air temperature is higher than the difference (Tca−T5), the condition 4 is satisfied and the initial opening degree of the electronic linear expansion valve 4 is set larger than that in the condition 5. As a result, a sufficient amount of circulating refrigerant can be secured, and an excessive increase in the discharge temperature can be suppressed by the cooling effect of the compressor 1 by the refrigerant.

  Although the above embodiment demonstrated the case where only one electronic linear expansion valve 4 was provided on the refrigerant circuit 16, for example, two electronic linear expansion valves 4a and 4b are provided on the refrigerant circuit 16 as shown in FIG. May be provided. In such a case, the upstream electronic linear expansion valve (4a during cooling operation, 4b during heating operation) controls the degree of subcooling of the refrigerant as a parameter, and the downstream electronic linear expansion valve (cooling operation). In the case of 4b at the time of operation and 4a) at the time of heating operation, there are cases where the discharge temperature or suction superheat degree (suction superheat) of the compressor 1 is controlled as a parameter. The initial opening degree of the downstream electronic linear expansion valve (4b during cooling operation and 4a during heating operation), which is controlled using suction superheat) as a parameter, is determined.

  DESCRIPTION OF SYMBOLS 1 Compressor, 2 Outdoor heat exchanger, 3 Outdoor blower, 4, 4a, 4b Electronic linear expansion valve, 5 Indoor heat exchanger, 6 Indoor blower, 7 Four way valve, 8 Outdoor temperature sensor, 9 Indoor temperature sensor, DESCRIPTION OF SYMBOLS 10 Control apparatus, 11 Accumulator, 12 Power receiver, 13a, 13b Outdoor piping temperature sensor, 14a, 14b Indoor piping temperature sensor, 15 Refrigerant piping, 16 Refrigerant circuit.

Claims (1)

At least in an air conditioner having a refrigerant circuit in which a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, and an indoor heat exchanger are sequentially connected by a refrigerant pipe,
An outside air temperature sensor that is provided on the outdoor heat exchanger side and detects an outside air temperature;
An indoor temperature sensor provided on the indoor heat exchanger side for detecting an indoor suction temperature;
Conditions for determining the initial opening of the expansion valve at the start of the compressor at the start of heating operation are set as at least conditions 4 and 5, and the outside temperature detected by the outside temperature sensor is a fourth predetermined value. When the temperature is lower, or when the outside air temperature is higher than the fourth predetermined value and the outside air temperature is lower than the difference between the indoor suction temperature detected by the indoor temperature sensor and the fifth predetermined value, the condition 5 is satisfied. As a result, the opening degree of the expansion valve is controlled so as to be the initial opening degree set in the condition 5, the outside air temperature is higher than a fourth predetermined value, and the outside air temperature is controlled by the indoor temperature sensor. when the detected indoor suction temperature and higher than the difference between the predetermined value of the fifth, as satisfies the condition 4, it is larger initial opening than the initial opening degree when the condition 5 Air conditioner, characterized in that said a control device for controlling the opening degree of the expansion valve so.

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