Air conditioner

Abstract

To improve energy saving performance in an air conditioner.SOLUTION: An air conditioner includes a refrigerant circuit (50) having a compressor (51), a condenser (52), and an evaporator (54), performs a refrigeration cycle by circulating a refrigerant in the refrigerant circuit (50), and cools air in the evaporator (54). The air conditioner includes a detecting unit (64) for detecting the rotation speed of the compressor (51), a gas supply pipe (55) for sending the refrigerant discharged from the compressor (51) to the evaporator (54) while bypassing the condenser (52), a control valve (56) provided in the gas supply pipe (55), and a controller (70) for controlling the opening of the control valve (56) on the basis of the rotation speed of the compressor (51) detected by the detecting unit (64).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an air conditioner.

Background Art

[0002] Conventionally, an air conditioner having a refrigerant circuit has been known. In the refrigerant circuit of the air conditioner, a refrigeration cycle is performed by circulating the refrigerant.

[0003] The amount of refrigerant passing through the evaporator in the refrigerant circuit is controlled according to the heat exchange amount between the refrigerant and air. However, when the heat exchange amount (air conditioning load) is small, the flow rate of the refrigerant decreases, which may cause the refrigerating machine oil to run out and the problem of the compressor burning out. In addition, when the heat exchange amount is below the capacity control lower limit of the air conditioner, the air conditioner may stop and stable air conditioning may not be possible. As a countermeasure, there is a method of increasing the refrigerant flow rate by flowing hot gas through the evaporator (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, conventionally, the flow rate of the hot gas has been controlled based on the suction pressure of the compressor. In order to prevent the suction pressure of the compressor from dropping, the hot gas is continuously flowed, so that the rotational speed of the compressor increases and it operates at the maximum output state. As a result, the energy saving performance is lowered.

[0006] An object of the present disclosure is to enhance the energy saving performance in an air conditioner.

Means for Solving the Problems

[0007] A first aspect of the present disclosure is directed to an air conditioner. The air conditioner includes a refrigerant circuit (50) having a compressor (51), a condenser (52), and an evaporator (54), circulates refrigerant in the refrigerant circuit (50) to perform a refrigeration cycle, and cools air in the evaporator (54). The air conditioner includes a detection unit (64) that detects the rotational speed of the compressor (51), a gas supply pipe (55) for bypassing the condenser (52) and sending the refrigerant discharged from the compressor (51) to the evaporator (54), a control valve (56) provided in the gas supply pipe (55), and a controller (70) that controls the opening degree of the control valve (56) based on the rotational speed of the compressor (51) detected by the detection unit (64).

[0008] According to the first aspect, by controlling the opening degree of the control valve (56) so that the rotational speed of the compressor (51) becomes a predetermined target rotational speed (for example, the minimum rotational speed at which problems such as seizure of the compressor (51) do not occur and the compressor (51) does not stop due to a decrease in the heat exchange amount), the compressor (51) can be stably operated without operating at maximum output, so that energy efficiency can be improved.

[0009] A second aspect of the present disclosure is, in the first aspect, the controller (70) controls the opening degree of the control valve (56) so that the rotational speed of the compressor (51) detected by the detection unit (64) becomes a predetermined target rotational speed.

[0010] In the second aspect, the rotational speed of the compressor (51) can be made closer to a predetermined target rotational speed.

[0011] A third aspect of the present disclosure is, in the second aspect, when the rotational speed of the compressor (51) is lower than the predetermined target rotational speed, the controller (70) increases the opening degree of the control valve (56), and when the rotational speed of the compressor (51) is higher than the predetermined target rotational speed, the controller (70) decreases the opening degree of the control valve (56).

[0012] In the third aspect, the rotational speed of the compressor (51) can be effectively brought closer to a predetermined target rotational speed.

[0013] In the fourth aspect of the present disclosure, in any one of the first to third aspects described above, the detection unit (64) is a frequency sensor that detects the drive frequency of the compressor (51).

[0014] In the fourth aspect, the rotational speed of the compressor (51) can be detected by a frequency sensor.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible without departing from the technical idea of the present disclosure. Since each drawing is for conceptually explaining the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for easy understanding. In each embodiment, modification example, and figure, the same or corresponding parts are denoted by the same reference numerals, and detailed descriptions and descriptions of accompanying effects and the like will not be repeated.

[0017] An embodiment will be described. The air conditioner (10) of the present embodiment performs air conditioning of a test chamber (100) used for an automobile driving test or the like.

[0018] The air conditioner (10) includes a utilization-side unit (20) and a heat source-side unit (40). The air conditioner also includes a refrigerant circuit (50).

[0019] -Utilization-Side Unit- As shown in FIG. 1, the user-side unit (20) is a so-called air handling unit. The user-side unit (20) includes a casing (25). An intake port (27) is formed on one end face of the casing (25), and an outlet port (28) is formed on the other end face of the casing (25). An air flow path (26) is formed inside the casing (25) from the intake port (27) to the outlet port (28).

[0020] The user-side unit (20) is connected to the test chamber (100) via an intake duct (16) and an outlet duct (17). The intake duct (16) is connected to the intake port (27) of the casing (25) and communicates the air flow path (26) with the internal space of the test chamber (100). The outlet duct (17) is connected to the outlet port (28) of the casing (25) and communicates the air flow path (26) with the internal space of the test chamber (100).

[0021] In the air flow path (26) inside the casing (25), a filter (31), an evaporator (54), an electric heater (32), and a user-side fan (33) are provided in order from the intake port (27) side to the outlet port (28) side. The filter (31) collects dust and the like contained in the air flowing in from the intake port (27). The evaporator (54) is connected to a refrigerant circuit (50) and cools the air. The electric heater (32) heats the air that has passed through the evaporator (54). The user-side fan (33) sucks in the air that has passed through the electric heater (32) and blows the air toward the outlet port (28).

[0022] <Operation]] The operation of the user-side unit (20) will be described.

[0023] When the user-side fan (33) operates, the air in the internal space of the test chamber (100) flows into the air flow path (26) inside the casing (25) through the intake duct (16). The air flowing through the air flow path (26) passes through the filter (31), the evaporator (54), and the electric heater (32) in sequence.

[0024] Air is cooled as it passes through the evaporator (54) and heated as it passes through the electric heater (32). Note that the electric heater (32) may temporarily stop heating the air. The air that has passed through the electric heater (32) is blown out from the user-side fan (33), flows into the blow duct (17), and then is blown into the internal space of the test chamber (100).

[0025] -Air temperature sensor, heater controller- The air conditioner (10) includes an air temperature sensor (36) and a heater controller (37).

[0026] The air temperature sensor (36) is provided in the blow duct (17) and measures the temperature of the air flowing through the blow duct (17). The measured value of the air temperature sensor (36) indicates the temperature of the air that the user-side unit (20) supplies to the internal space of the test chamber (100).

[0027] The measured value of the air temperature sensor (36) is input to the heater controller (37). The heater controller (37) controls the heating amount of the electric heater (32) based on the measured value of the air temperature sensor (36). Specifically, the heater controller (37) adjusts the heating amount of the electric heater (32) so that the measured value of the air temperature sensor (36) becomes the set air temperature. When the measured value of the air temperature sensor (36) is lower than the set air temperature, the heater controller (37) increases the heating amount of the electric heater (32). When the measured value of the air temperature sensor (36) is higher than the set air temperature, the heater controller (37) decreases the heating amount of the electric heater (32).

[0028] -Refrigerant circuit- The refrigerant circuit (50) is a closed circuit filled with refrigerant. The refrigerant circuit (50) performs a refrigeration cycle by circulating the refrigerant.

[0029] As shown in FIG. 2, the refrigerant circuit (50) includes a compressor (51), a condenser (52), an expansion valve (53), and an evaporator (54). In the refrigerant circuit (50), the condenser (52), the expansion valve (53), and the evaporator (54) are arranged in order from the discharge port to the suction port of the compressor (51). In the refrigerant circuit (50), a receiver (57) for storing the refrigerant that has become surplus due to fluctuations in the heat load is provided between the condenser (52) and the expansion valve (53).

[0030] The compressor (51) compresses and discharges the inhaled refrigerant. Although not shown, the compressor (51) includes a compression mechanism and an electric motor for driving the compression mechanism. The condenser (52) is a cross-fin type air heat exchanger that exchanges heat between the refrigerant and outdoor air. The expansion valve (53) is an electric expansion valve with variable opening. The evaporator (54) is a cross-fin type air heat exchanger that exchanges heat between the refrigerant and the air in the air flow path (26).

[0031] Further, the refrigerant circuit (50) includes a gas supply pipe (55). The gas supply pipe (55) constitutes a gas supply passage. The gas supply pipe (55) bypasses the condenser (52) and sends the refrigerant discharged from the compressor (51) to the evaporator (54). One end of the gas supply pipe (55) is connected to the pipe between the discharge port of the compressor (51) and the condenser (52). The other end of the gas supply pipe (55) is connected to the pipe between the expansion valve (53) and the evaporator (54). A regulating valve (56) is provided in the gas supply pipe (55). The regulating valve (56) is an electric valve with variable opening.

[0032] 〈Refrigeration cycle〉 The refrigeration cycle performed by the refrigerant circuit (50) will be described.

[0033] When the compressor (51) operates, the refrigerant circulates in the refrigerant circuit (50). The refrigerant discharged by the compressor (51) flows into the condenser (52), releases heat to the outdoor air passing through the condenser (52), and condenses. The refrigerant flowing out of the condenser (52) is depressurized in the process of passing through the expansion valve (53), and then flows into the evaporator (54).

[0034] When the regulating valve (56) is open, a part of the gas refrigerant (hot gas) discharged from the compressor (51) flows into the gas supply pipe (55). The gas refrigerant flowing through the gas supply pipe (55) flows into the evaporator (54) together with the refrigerant that has passed through the expansion valve (53). The refrigerant flowing into the evaporator (54) absorbs heat from the air passing through the evaporator (54) and evaporates. The refrigerant flowing out of the evaporator (54) is sucked into the compressor (51) and compressed. The compressor (51) compresses and discharges the sucked refrigerant.

[0035] -Heat source unit- The heat source side unit (40) is provided with a compressor (51) and a condenser (52) of the refrigerant circuit (50). The heat source side unit (40) also includes a heat source side fan (41) and an inverter (42). The heat source side fan (41) supplies outdoor air to the condenser (52). Although not shown, an external power source such as a commercial power supply is connected to the inverter (42). The inverter (42) converts the supplied AC frequency to the set frequency and supplies the AC of the set frequency to the motor of the compressor (51). When the output frequency of the inverter (42) is changed, the rotational speed of the compressor (51) changes.

[0036] The heat source side unit (40) includes a suction pressure sensor (46). The suction pressure sensor (46) is connected to the refrigerant circuit (50). The suction pressure sensor (46) is attached to the pipe connected to the suction port of the compressor (51) and measures (detects) the pressure of the refrigerant sucked into the compressor (51).

[0037] 〈Compressor controller〉 The heat source side unit (40) includes a compressor controller (47). The measured value (detection result) of the suction pressure sensor (46) is input to the compressor controller (47). The compressor controller (47) is configured to control the rotational speed of the compressor (51) based on the measured value of the suction pressure sensor (46).

[0038] Specifically, the compressor controller (47) adjusts the rotational speed of the compressor (51) such that the measured value of the suction pressure sensor (46) becomes the set suction pressure. When the measured value of the suction pressure sensor (46) is lower than the set suction pressure, the compressor controller (47) decreases the rotational speed of the compressor (51) by decreasing the output frequency of the inverter (42). When the measured value of the suction pressure sensor (46) is higher than the set suction pressure, the compressor controller (47) increases the rotational speed of the compressor (51) by increasing the output frequency of the inverter (42).

[0039] -Sensor- The air conditioner (10) includes an outlet pressure sensor (62), an outlet temperature sensor (63), and a frequency sensor (64).

[0040] The outlet pressure sensor (62) and the outlet temperature sensor (63) are attached to a pipe connected to the outlet of the evaporator (54). The outlet pressure sensor (62) detects the pressure of the refrigerant flowing out of the evaporator (54) and the pressure of the refrigerant flowing from the evaporator (54) toward the compressor (51). The outlet pressure sensor (62) is an example of a third detection unit. The outlet temperature sensor (63) detects the temperature of the refrigerant flowing out of the evaporator (54) and the temperature of the refrigerant flowing from the evaporator (54) toward the compressor (51). The outlet pressure sensor (62) is an example of a second detection unit.

[0041] The frequency sensor (64) is provided on the power supply electrical wiring that connects the inverter (42) to the electric motor of the compressor (51). The frequency sensor (64) measures the output frequency of the inverter (42). The measured value of the frequency sensor (64) is the alternating current frequency that the inverter (42) supplies to the compressor (51), or in other words, the drive frequency of the compressor (51).

[0042] -Controller- The air conditioner (10) includes an expansion valve controller (75) and a regulating valve controller (76). The compressor controller (47), the expansion valve controller (75), and the regulating valve controller (76) constitute a controller (70) that controls the expansion valve (53) and the regulating valve (56).

[0043] <Expansion valve controller> The measured value of the outlet pressure sensor (62) and the measured value of the outlet temperature sensor (63) are input to the expansion valve controller (75). The expansion valve controller (75) is configured to calculate a first command value regarding the opening degree of the expansion valve (53) based on the measured values of the outlet pressure sensor (62) and the outlet temperature sensor (63).

[0044] First, the expansion valve controller (75) calculates the superheat degree of the refrigerant at the outlet of the evaporator (54). The expansion valve controller (75) sets the value obtained by subtracting the saturation temperature Ts of the refrigerant corresponding to the measured value of the outlet pressure sensor (62) from the measured value T of the outlet temperature sensor (63) as the superheat degree SH (=T - Ts) of the refrigerant at the outlet of the expansion valve (53).

[0045] Next, the expansion valve controller (75) calculates the opening degree of the expansion valve (53) such that the superheat degree of the refrigerant at the outlet of the evaporator (54) becomes the set superheat degree. The opening degree calculated by this expansion valve controller (75) is the first opening degree. The expansion valve controller (75) determines the calculated first opening degree as the first command value regarding the opening degree of the expansion valve (53). The regulating valve controller (76) transmits the determined first command value to the expansion valve (53). As a result, the opening degree of the expansion valve (53) becomes the first opening degree corresponding to the first command value.

[0046] Here, when the refrigerant at the outlet of the evaporator (54) becomes wet, there is a risk that liquid refrigerant is sucked into the compressor (51), and as a result, the compressor (51) may be damaged. Therefore, in order to prevent damage to the compressor (51), it is necessary to keep the refrigerant at the outlet of the evaporator (54) in a gas single-phase state.

[0047] On the one hand, when the opening degree of the expansion valve (53) is changed, the amount of refrigerant flowing into the evaporator (54) changes, and as a result, the state of the refrigerant at the outlet of the evaporator (54) changes. Therefore, the expansion valve controller (75) calculates the opening degree of the expansion valve (53) such that the superheat degree of the refrigerant at the outlet of the evaporator (54) becomes the set superheat degree (for example, a value within the range of 5K or more and 10K or less), so as to completely gasify the refrigerant at the outlet of the evaporator (54).

[0048] When the opening degree of the expansion valve (53) decreases, the amount of refrigerant flowing into the evaporator (54) decreases, and as a result, the superheat degree of the refrigerant at the outlet of the evaporator (54) increases. Therefore, when the superheat degree of the refrigerant at the outlet of the evaporator (54) is lower than the set superheat degree, the expansion valve controller (75) determines an opening degree smaller than the current opening degree of the expansion valve (53) as the first command value.

[0049] On the other hand, when the opening degree of the expansion valve (53) increases, the amount of refrigerant flowing into the evaporator (54) increases, and as a result, the superheat degree of the refrigerant at the outlet of the evaporator (54) decreases. Therefore, when the superheat degree of the refrigerant at the outlet of the evaporator (54) is higher than the set superheat degree, the expansion valve controller (75) determines an opening degree larger than the current opening degree of the expansion valve (53) as the first command value.

[0050] 〈Regulating Valve Controller〉 The measured value of the frequency sensor (64) is input to the regulating valve controller (76). The regulating valve controller (76) is configured to calculate a second command value regarding the opening degree of the regulating valve (56) based on the measured value of the frequency sensor (64). The measured value of the frequency sensor (64) is, in other words, the rotational speed of the compressor (51).

[0051] Specifically, the control valve controller (76) calculates the opening degree of the control valve (56) such that the measured value of the frequency sensor (64) becomes the set frequency. The opening degree calculated by this control valve controller (76) is the second opening degree. The control valve controller (76) determines the calculated second opening degree as the second command value regarding the opening degree of the control valve (56). The control valve controller (76) transmits the determined second command value to the control valve (56). As a result, the opening degree of the control valve (56) becomes the second opening degree corresponding to the second command value.

[0052] Here, when the rotational speed of the compressor (51) is low, the flow rate of the refrigerant flowing through the refrigerant circuit (50) becomes low, and the refrigerating machine oil discharged together with the refrigerant from the compressor (51) tends to stay in the evaporator (54), piping, etc. Therefore, when the compressor (51) operates for a long time at a relatively low rotational speed (for example, a state of 20% or less of the maximum rotational speed), the amount of refrigerating machine oil staying outside the compressor (51) increases, and the amount of refrigerating machine oil remaining inside the compressor (51) decreases. As a result, the amount of refrigerating machine oil supplied to the sliding part of the compressor (51) becomes insufficient, and the compressor (51) may be damaged.

[0053] On the other hand, if the rotational speed of the compressor (51) is maintained at a relatively high rotational speed (for example, 80% or more of the maximum rotational speed), the amount of refrigerating machine oil returning to the compressor (51) together with the refrigerant is ensured. Therefore, a sufficient amount of refrigerating machine oil stored in the compressor (51) is ensured, and damage to the compressor (51) is prevented beforehand.

[0054] Therefore, the control valve controller (76) calculates the opening degree of the control valve (56) such that the measured value of the frequency sensor (64) becomes the set frequency. The set frequency is, for example, a frequency of about 60% of the maximum output frequency in terms of specifications. The measured value of the frequency sensor (64) is the actually measured value of the output frequency of the inverter (42). Therefore, when the measured value of the frequency sensor (64) becomes the set frequency, the rotational speed of the compressor (51) becomes the predetermined target rotational speed, and as a result, the amount of refrigerating machine oil returning to the compressor (51) together with the refrigerant is ensured.

[0055] Here, when the cooling load of the evaporator (54) (specifically, the amount of heat that the refrigerant takes from the air in the evaporator (54)) becomes small, the amount of refrigerant evaporated in the evaporator (54) decreases, so the measured value of the suction pressure sensor (46) decreases. Therefore, if nothing is done, the compressor controller (47) decreases the rotational speed of the compressor (51) in order to keep the measured value of the suction pressure sensor (46) at the set suction pressure. In such a case, by increasing the flow rate of the gas refrigerant flowing through the gas supply pipe (55), a decrease in the rotational speed of the compressor (51) can be suppressed.

[0056] The reason will be explained. The refrigerant that has passed through the expansion valve (53) and the gas refrigerant flowing through the gas supply pipe (55) flow into the evaporator (54) after being mixed. A part of the liquid refrigerant contained in the refrigerant that has passed through the expansion valve (53) is heated and evaporated by the gas refrigerant flowing in from the gas supply pipe (55). Therefore, when the opening degree of the regulating valve (56) expands and the flow rate of the gas refrigerant flowing through the gas supply pipe (55) increases, the amount of gas refrigerant that the compressor (51) sucks from the evaporator (54) increases. As a result, a decrease in the measured value of the suction pressure sensor (46) is suppressed, and a decrease in the rotational speed of the compressor (51) is also suppressed.

[0057] Therefore, when the measured value of the frequency sensor (64) is lower than the set frequency, the regulating valve controller (76) determines a larger opening degree than the current opening degree of the regulating valve (56) as the second command value. In other words, when the rotational speed of the compressor (51) is lower than a predetermined target rotational speed, the regulating valve controller (76) increases the opening degree of the regulating valve (56) to be larger than the current opening degree. The predetermined target rotational speed is, for example, a speed about 60% of the maximum rotational speed in terms of specifications.

[0058] On the one hand, when the measured value of the frequency sensor (64) is higher than the set frequency, there is a possibility that the rotational speed of the compressor (51) can be maintained at a predetermined target rotational speed or higher even if the opening degree of the regulating valve (56) is reduced. Therefore, when the measured value of the frequency sensor (64) is higher than the set frequency, the regulating valve controller (76) determines a smaller opening degree than the current opening degree of the regulating valve (56) as the second command value. In other words, when the rotational speed of the compressor (51) is higher than the predetermined target rotational speed, the regulating valve controller (76) reduces the opening degree of the regulating valve (56) to be smaller than the current opening degree.

[0059] The regulating valve controller (76) determines a value such that the measured value of the frequency sensor (64) becomes the set frequency as the second command value. In other words, the regulating valve controller (76) controls the opening degree of the regulating valve (56) so that the rotational speed of the compressor (51) becomes the predetermined target rotational speed. As a result, while ensuring the amount of refrigerant oil returning to the compressor (51) together with the refrigerant, energy efficiency can be improved.

[0060] By the way, if the opening degree of the regulating valve (56) changes greatly in a short time, the pressure of the refrigerant flowing into the evaporator (54) changes, and accordingly, the expansion valve controller (75) may change the opening degree of the expansion valve (53). Therefore, the regulating valve controller (76) determines the second command value so that the change in the opening degree of the regulating valve (56) is a gentle change to the extent that the measured value of the inlet side pressure sensor (61) is substantially kept constant.

[0061] As described above, the regulating valve controller (76) controls the opening degree of the regulating valve (56) so that the rotational speed of the compressor (51) becomes the predetermined target rotational speed. According to this, if it is set as the minimum rotational speed such that problems such as seizure occurring in the compressor (51) and the compressor (51) stopping due to a decrease in the heat exchange amount of the evaporator (54) do not occur for the predetermined target rotational speed, the compressor (51) can be stably operated without operating at the maximum output, so energy efficiency can be improved.

[0062] 《Other Embodiments》 For the air conditioner (10) of the above embodiment, the following modifications may be applied. Note that the following modifications may be appropriately combined or replaced as long as the functions of the air conditioner (10) are not impaired.

[0063] The object for which the air conditioner (10) of the present embodiment performs air conditioning is not limited to the laboratory (100). The air conditioner (10) of the present embodiment may be used, for example, for air conditioning a large space such as a hall.

[0064] Also, in the air conditioner (10) of the present embodiment, each of the expansion valve controller (75) and the regulating valve controller (76) may include a microcomputer. Also, the controller (70) may be constituted by one microcomputer. Further, the microcomputer constituting the controller (70) may be configured to perform the control operations performed by at least one of the compressor controller (47) and the heater controller (37).

[0065] Also, in the air conditioner (10) of the present embodiment, the measured value of the frequency sensor (64) is configured to indicate the rotational speed of the compressor (51), but the present invention is not limited to this. The command value to the inverter (42) for driving the electric motor of the compressor (51) may be configured to indicate the rotational speed of the compressor (51). That is, the detection unit may be configured to acquire the command value to the inverter (42).

[0066] As described above, the embodiments and modifications have been explained. It will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Also, the elements according to the above embodiments, modifications, and other embodiments may be appropriately combined or replaced. Also, the descriptions such as "first", "second", "third",... in the specification and claims are used to distinguish the clauses to which these descriptions are given, and do not limit even the number and order of these clauses.

Industrial Applicability

[0067] As described above, the present disclosure is useful for an air conditioner.

Description of Reference Numerals

[0068] 10 Air conditioner 50 Refrigerant circuit 51 Compressor 52 Condenser 53 Expansion valve 54 Evaporator 55 Gas supply pipe 56 Control valve 64 Frequency sensor (detection unit) 70 Controller

Claims

1. An air conditioner comprising a refrigerant circuit (50) having a compressor (51), a condenser (52), and an evaporator (54), performing a refrigeration cycle by circulating a refrigerant in the refrigerant circuit (50), and cooling air in the evaporator (54), a detection unit (64) for detecting the rotational speed of the compressor (51), a gas supply pipe (55) for bypassing the condenser (52) and sending the refrigerant discharged from the compressor (51) to the evaporator (54), a regulating valve (56) provided in the gas supply pipe (55), and a controller (70) for controlling the opening degree of the regulating valve (56) based on the rotational speed of the compressor (51) detected by the detection unit (64). The air conditioner according to claim 1, further comprising:

2. The air conditioner according to claim 1, wherein the controller (70) controls the opening degree of the regulating valve (56) such that the rotational speed of the compressor (51) detected by the detection unit (64) becomes a predetermined target rotational speed.

3. The controller (70) is configured to: increase the opening degree of the regulating valve (56) when the rotational speed of the compressor (51) is lower than the predetermined target rotational speed, and decrease the opening degree of the regulating valve (56) when the rotational speed of the compressor (51) is higher than the predetermined target rotational speed. The air conditioner according to claim 2.

4. The air conditioner according to any one of claims 1 to 3, wherein the detection unit (64) is a frequency sensor for detecting the driving frequency of the compressor (51).

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