JPH0861815A - Air conditioner - Google Patents

Abstract

(57) [Summary] [Object] To provide an air conditioner capable of optimizing the refrigeration cycle temperature even when the amount of refrigerant in the entire refrigeration cycle is in a state other than a predetermined value. [Structure] Outdoor-side control device 11 and indoor-side control device 12
Is a variation range of the discharge gas superheat degree when the opening degree of the electronic expansion valve 10 is changed, the condensation temperature is detected from the indoor liquid pipe temperature sensor 16 or the outdoor liquid pipe temperature sensor 18, and these detection data are detected. The refrigeration cycle is stabilized by changing the opening of the electronic expansion valve 10 by the opening change width calculated so as to reach the target discharge gas superheat degree. [Effect] The refrigeration cycle can be stabilized by using a simple control system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner having a refrigerating cycle, and more particularly to an air conditioner having a detecting means for properly determining the amount of refrigerant in the refrigerating cycle.

[0002]

2. Description of the Related Art As such an air conditioner, a valve opening calculating means, a temperature difference checking means, and a valve opening correcting means are periodically synchronized as in the technique disclosed in Japanese Patent Laid-Open No. 61-96376. Some of them are operated to control the valve opening of an electrically operated refrigerant control valve to improve controllability with respect to fluid temperature such as room temperature.

That is, when the temperature difference checking means checks the wet state of the outlet of the utilization side coil during cooling or the flush state of the outlet of the utilization side coil during heating, the valve opening degree correction means sets the valve opening degree as a unit. A command is issued to throttle the valve opening. As a result, the refrigerant control valve is throttled, and the valve opening is automatically adjusted so as to return the wet state or the flush state to the proper superheat degree or subcool degree.

The flush state means that the refrigerant is not in a completely liquid state but a part of the liquid refrigerant is evaporated and gasified. When the flash condition occurs, the capacity of the expansion valve is significantly reduced.

On the other hand, as another example of the conventional air conditioner, there is a valve opening detecting means, a wetness determining means, an abnormal dryness determining means, and these determinations, as in the technique described in JP-A-61-220206. An abnormal signal output unit that outputs an abnormal signal in response to the output of the unit is provided to determine whether the intake gas refrigerant is abnormally wet or abnormally dry.

That is, the valve opening degree when the intake gas refrigerant becomes abnormally dry and the valve opening degree when the intake gas refrigerant becomes abnormally wet are stored in the memory in advance, and the valve opening degree during operation and the memory are stored in the memory. The refrigeration cycle temperature is monitored so that it does not become abnormal by comparing it with the stored valve opening.

[0007]

However, in one of the conventional air conditioners described above, during cooling, whether the refrigerant at the outlet of the utilization side coil is in a state close to a wet region in a dry region, or heating At this time, the valve opening is corrected depending on whether the liquid seal area is maintained close to the flash area.Therefore, if the refrigerant is excessively enclosed in the refrigeration cycle, the refrigerant at the outlet of the utilization side coil The condition of is in a wet region during cooling, and when it is maintained in a state not close to the flush region of the liquid seal region during heating, it becomes difficult to correct the valve opening by the temperature difference checking means. .

This is because even if it is possible to judge whether the refrigeration cycle temperature is proper or not by the degree of opening / closing of the electrically operated refrigerant control valve, the temperature difference check area is narrow, and therefore the refrigeration cycle temperature may be exceeded due to the excess or deficiency of the refrigerant amount. This is because it becomes impossible to determine whether or not is appropriate.

Further, in the other conventional air conditioner, when the refrigeration cycle is filled with an appropriate amount of refrigerant, it is possible to check the opening / closing degree of the valve opening. It is not possible to determine the excess or deficiency of. Further, no consideration has been given to optimizing the refrigeration cycle temperature only by determining whether the refrigeration cycle temperature is abnormal or normal.

Therefore, an object of the present invention is to provide an air conditioner capable of optimizing the refrigeration cycle temperature even when the refrigerant amount in the entire refrigeration cycle is in a state other than a predetermined value. To do.

[0011]

The air conditioner of the present invention comprises:
A compressor, an outdoor heat exchanger, an electronic expansion valve, an air conditioner that constitutes a refrigeration cycle by sequentially connecting an indoor heat exchanger and an accumulator, and compression when the opening degree of the electronic expansion valve is changed by a predetermined value. A detection means for detecting a change in the superheat degree of the machine discharge gas, and a judgment means for judging whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in the superheat degree detected by the detection means. And

Further, in the air conditioner of the present invention, the judging means judges that the proper amount of refrigerant is enclosed when the change range of the degree of superheat detected by the detecting means is in a predetermined region, and the degree of superheat is determined. If the change width of is less than the predetermined region, it is determined that the refrigerant is excessively sealed during the refrigeration cycle, and if the change range of the superheat degree exceeds the predetermined region, during the refrigeration cycle. It is preferable to have an electronic expansion valve opening control means for judging that the refrigerant is in a shortage state and adjusting the opening change width of the electronic expansion valve according to the judgment result of this judgment means.

Further, the air conditioner of the present invention is an air conditioner in which a compressor, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger and an accumulator are sequentially connected to form a refrigeration cycle. Detecting means for detecting the temperature change of the compressor discharge gas when the opening degree of is changed by a predetermined value, and the refrigerant amount in the refrigeration cycle based on the temperature change of the compressor discharge gas detected by this detecting means. And a determination means for determining whether or not is appropriate.

Further, the air conditioner of the present invention is an air conditioner in which a compressor, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger and an accumulator are sequentially connected to form a refrigeration cycle. Detecting means for detecting the difference between the inlet and outlet temperatures of the indoor heat exchanger when the opening degree of is changed by a predetermined value, and the outdoor heat exchanger when the opening degree of the electronic expansion valve is changed by a predetermined value Second to detect the difference of inlet and outlet temperature
In the case of the cooling operation, it is determined whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in the degree of superheat detected by the first detecting means in the case of the cooling operation, and in the case of the heating operation, the second
It is characterized by having a judging means for judging whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in the degree of superheat detected by the detecting means.

Further, in the air conditioner of the present invention, when the judging means judges that the amount of refrigerant in the refrigeration cycle is not appropriate, the electronic expansion valve opening control for changing the adjustment change width of the opening of the electronic expansion valve. It is preferable to have means.

Further, the air conditioner of the present invention preferably has electronic expansion valve opening degree control means for changing a PID control constant for controlling the opening degree of the electronic expansion valve according to the judgment result of the judgment means.

[0017]

In the air conditioner of the present invention, the electronic expansion valve is used as a pressure reducing device, and the response of the refrigeration cycle to a change in the opening of the electronic expansion valve is detected by the detection means, and the amount of refrigerant in the refrigeration cycle is detected according to the response. Is provided with a determining means for determining whether the refrigeration cycle is stabilized by adjusting the opening change range of the electronic expansion valve according to the determination result of the determining means. be able to.

Further, according to the present air conditioner, by preliminarily enclosing the refrigerant in the refrigerating cycle by a predetermined value, the length of the connecting liquid pipe in the refrigerating cycle is varied, and so on. Even if the relative amount of the refrigerant changes, the opening change width of the electronic expansion valve can be controlled according to the response of the refrigeration cycle, so that the refrigeration cycle can be stabilized in an optimum state. .

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a refrigeration cycle system diagram showing an air conditioner according to an embodiment of the present invention. This air conditioner has 1
Connecting the indoor unit 8 which is one indoor unit and the outdoor unit 1 which is one outdoor unit with the connecting liquid pipe 6 and the connecting gas pipe 7
It is a pair type air conditioner connected by. The outdoor unit 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4,
The indoor unit 8 is equipped with an accumulator 5, and the indoor unit 8 is equipped with an indoor heat exchanger 9 and an electronic expansion valve 10, which constitute a refrigeration cycle.

Further, the present air conditioner is provided with a temperature sensor for detecting the refrigerating cycle temperature for each of the component devices constituting the refrigerating cycle. That is, in the outdoor unit 1, a discharge gas temperature sensor 14 that detects the temperature of the refrigerant discharged from the compressor 2 and an outdoor liquid that is mounted on the heat exchanger inlet side and detects the refrigerant gas temperature on the heating low pressure side. A pipe temperature sensor 18 and an outdoor gas pipe temperature sensor 17 which is attached to the heat exchanger outlet side and detects the refrigerant gas temperature on the heating low pressure side are provided. A pressure sensor 13 for detecting the discharge gas pressure is attached to the discharge port of the compressor 2. Then, the detection signals of the respective sensors provided in the outdoor unit 1 are output to the outdoor side control device 11
Be absorbed in.

Further, the indoor unit 8 is provided with an indoor liquid pipe temperature sensor 16 mounted on the heat exchanger inlet side for detecting the refrigerant gas temperature on the cooling low pressure side, and on the heat exchanger outlet side. An indoor gas pipe temperature sensor 15 for detecting the refrigerant gas temperature on the cooling low pressure side is provided. Then, the detection signals of the respective sensors provided in the indoor unit 8 are taken into the indoor control device 12.

Then, either the outdoor control device 11 or the indoor control device 12 controls the opening degree of the electronic expansion valve 10 to change the opening degree, and the time rate of change of the discharge gas superheat degree with respect to the opening degree change. Ask for. Here, the time rate of change of the discharge gas superheat degree is determined by the discharge gas temperature sensor 14, the indoor gas pipe temperature sensor 15, the indoor liquid pipe temperature sensor 16, the outdoor gas pipe temperature sensor 17, or the outdoor liquid pipe temperature sensor 18. The outdoor control device 11 or the indoor control device 12 calculates based on the detected value of. In addition, the outdoor control device 11 or the indoor control device 12 determines whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the temporal change rate of the discharge gas superheat degree calculated above.

Next, details of the operation of this embodiment will be described. In the refrigeration cycle during cooling, the gas refrigerant is compressed into high temperature and high pressure by the compressor 2 provided in the outdoor unit 1. This compressed gas refrigerant is sent to the outdoor heat exchanger 4 via the four-way valve 3 and condensed there to become a liquid refrigerant.

This liquid refrigerant is sent to the indoor unit 8 through the connecting liquid pipe 6 and adiabatically expanded by the electronic expansion valve 10. The expanded refrigerant evaporates in the indoor heat exchanger 9. The evaporated refrigerant returns to the outdoor unit 1 via the connecting gas pipe 7, is sent to the accumulator 5 via the four-way valve 3, where it is separated into gas and liquid and is sucked into the compressor 2.

On the other hand, in the refrigeration cycle during heating,
A refrigerant circuit is formed which circulates in the opposite direction to the refrigerant circuit during cooling. That is, the gas refrigerant compressed to a high temperature and high pressure by the compressor 2 provided in the outdoor unit 1 is liquefied in the indoor heat exchanger 9 provided in the indoor unit 8,
The electronic expansion valve 10 adiabatically expands, the refrigerant evaporates in the outdoor heat exchanger 4, and returns to the outdoor unit 1.

Next, the operation of the outdoor control device 11 and the indoor control device 12 will be described. FIG. 2 is a graph showing changes in the discharge gas superheat degree with respect to changes in the opening degree of the electronic expansion valve 10 in the present air conditioner.

As shown in FIG. 2, when the refrigeration cycle becomes stable after the compressor 2 is started, the indoor controller 12 closes the opening of the electronic expansion valve 10 by a predetermined value ΔPo. In addition, the outdoor control device 11 or the indoor control device 1
2 calculates the discharge gas superheat degree representing the refrigeration cycle temperature before and after the opening of the electronic expansion valve 10 is changed.

The outdoor control device 11 and the indoor control device 12 change the calculation result of the discharge gas superheat degree and the number of increase / decrease pulses ΔP of the expansion valve opening when the refrigeration cycle shown in FIG. 3 is stabilized. And the discharge gas superheat degree change width, the increase / decrease pulse number ΔP of the expansion valve opening is determined. The indoor control device 12 controls the opening degree of the electronic expansion valve 10 based on the increase / decrease pulse number ΔP of the expansion valve opening degree, thereby stabilizing the refrigeration cycle.

That is, the increase / decrease pulse number Δ for controlling the opening degree of the electronic expansion valve 10 in accordance with the change width ΔT of the discharge gas superheat degree which changes according to the change width ΔPo of the expansion valve opening degree.
By changing P, the discharge gas superheat degree can be stabilized at the superheat degree at which the refrigeration cycle temperature is optimum.

FIG. 4 is a flow chart showing an example of the operation of controlling the opening degree of the electronic expansion valve 10 by the outdoor control device 11 and the indoor control device 12 described above. First, the initial opening of the electronic expansion valve 10 and variables used for various processes are initialized (S1, S2). Next, the condensation temperature Tc is detected by the outdoor liquid pipe temperature sensor 18 during the cooling operation and by the indoor pipe liquid temperature sensor 16 during the heating operation. Then, based on the relationship of the target discharge gas superheat degree SHset with respect to the condensation temperature Tc shown in FIG. 5, the target discharge gas superheat degree SHset with respect to the above-mentioned condensation temperature Tc is set by the outdoor side control device 11 or the indoor side control device 12. Calculate and determine. It should be noted that the target discharge gas superheat degree SHset
Are used in the process of step 5.

The pressure sensor 13 detects the discharge gas pressure of the compressor 2, and the discharge gas temperature sensor 14 detects the discharge gas temperature. Based on these detection and calculation results, the outdoor side controller 11 determines the saturation temperature. And the discharge gas superheat degree SH (n) is calculated from the difference between the saturation temperature and the discharge gas temperature. The detected discharge gas superheat degree SH (n) is used in the process of step 5.

Then, the discharge gas superheat degree SH (n) detected as described above and the target discharge gas superheat degree SHset.
The opening degree P (n) of the electronic expansion valve 10 is controlled (S6 to S14) until the difference between and becomes equal to or less than a certain convergence determination value ΔSHL (S5). Here, the control of the electronic expansion valve 10 is performed by changing the expansion valve opening degree based on the graph showing the number of pulses of the expansion valve opening increase / decrease with respect to the change of the discharge gas superheat degree shown in FIG. n) adjusts the expansion valve opening degree so as to approach the target discharge gas superheat degree SHset.

As a concrete control procedure of the opening degree P (n) of the electronic expansion valve 10, first, the detected discharge gas superheat degree SH is detected.
(N) is compared with the target discharge gas superheat degree SHset (S6). Here, when the detected discharge gas superheat degree SH (n) is larger than the target discharge gas superheat degree SHset, control is performed to increase the opening degree of the electronic expansion valve 10 by a predetermined value (S7 to S10). . Further, at this time, in order to prevent the electronic expansion valve 10 from being opened too much, the relational expression for changing the opening degree of the electronic expansion valve 10 is selectively used in the two processes of step 9 and step 10.

On the other hand, the discharge gas superheat degree SH detected in step 6 is higher than the target discharge gas superheat degree SHset.
If (n) is smaller, the electronic expansion valve 10 is moved by a predetermined value.
The control is performed to reduce the opening degree of (S11 to S14).
Also at this time, in order to prevent the electronic expansion valve 10 from being closed too much, the relational expression for changing the opening degree of the electronic expansion valve 10 is selectively used in the two processes of step 13 and step 14. .

When the PI control is used to control the opening degree of the electronic expansion valve 10 and the feedback control is performed so that the detected discharge gas superheat degree approaches the target discharge gas superheat degree, the refrigeration cycle temperature with respect to the expansion valve opening change. Responsiveness does not change.

As a result, when there is excess refrigerant in the refrigeration cycle, even if the expansion valve opening is changed, the change in the refrigeration cycle temperature is small, and the discharge gas superheat degree does not approach the target discharge gas superheat degree. The problem arises that the valve is overthrottled.

On the other hand, when the amount of refrigerant is too small in the refrigeration cycle, the speed of increasing the opening degree of the expansion valve cannot follow the increase in the discharge gas superheat and the temperature of the compressor 2 rises. There is a problem of passing.

Further, the PID is used for controlling the opening degree of the electronic expansion valve 10.
When control is used, since a complicated control system is configured as shown in the following mathematical formulas 1 and 2, there is a problem that it takes a lot of time to determine each coefficient in the following mathematical formula.

[0040]

[Formula 1] PTH (n) = PTH (n-1) + ΔPTH Where, PTH (n): Current electronic expansion valve opening pulse number PTH (n-1): Previous electronic expansion valve opening pulse number ΔPTH : Number of pulses for increasing / decreasing expansion valve opening.

[0041]

## EQU2 ## ΔPTH = KPTH {ΔTH (n) -ΔTH (n-1)}
+ K iTH ΔTH (n) ΔS where ΔTH (n): THset-TH ΔTH (n-1): Previous TH (n) KPTH, KiTH: Coefficient ΔS: Sampling time interval THset: Control target discharge gas superheat degree TH: Discharge Gas superheat.

As a result, according to the air conditioner of this embodiment, the response of the refrigeration cycle to changes in the opening of the electronic expansion valve 10 is captured, and the change in refrigeration cycle temperature due to changes in the opening of the electronic expansion valve 10 is small. Sometimes, the variation range of the opening degree of the electronic expansion valve 10 is increased, and conversely, when the variation of the refrigeration cycle temperature is large, the variation range of the opening degree of the electronic expansion valve 10 is reduced. The degree of superheat can be approached, and the refrigeration cycle can be stabilized in an optimum state.

Further, according to the air conditioner of the present embodiment, the lengths of the connecting liquid pipe 6 and the connecting gas pipe 7 connecting the outdoor unit 1 and the indoor unit 8 are such that the condition of the installation location of the air conditioner and the like. In the case of fluctuations due to the above, by enclosing the refrigerant with a predetermined value in advance, even if the lengths of the connecting liquid pipe 6 and the connecting gas pipe 7 are changed thereafter, the electronic expansion is performed according to the response of the refrigeration cycle. Since the opening change width of the valve 10 can be controlled, the refrigeration cycle can be stabilized in an optimum state.

In the air conditioner of this embodiment, the control system can be constructed by a simple method without constructing a complicated control system, so that the product development period can be shortened.

FIG. 6 is a refrigeration cycle system diagram showing the flow of the refrigerant during cooling in the air conditioner shown in FIG. The arrows in the figure indicate the flow of the refrigerant during cooling. On the other hand, FIG. 7 is a Mollier diagram of the refrigeration cycle shown in FIG.

Here, the points a, b, c, d, e and f in the Mollier diagram of FIG. 7 are the states of the respective parts a, b, c, d, e and f in the refrigeration cycle of FIG. Is shown. Further, the straight line A in FIG. 7 shows a state in which an appropriate amount of refrigerant is present in the refrigeration cycle. Further, the straight line a indicates the state in which an excessive amount of refrigerant is present in the refrigeration cycle. Further, the straight line c indicates the state in which the refrigerant amount is insufficient in the refrigeration cycle.

FIG. 8 is a graph showing the opening control state of the electronic expansion valve in the air conditioner of this embodiment and the opening control state of the electronic expansion valve in the air conditioner using the conventional feedback control. This graph shows the opening control of the electronic expansion valve when an excessive amount of refrigerant is present in the refrigeration cycle. In the conventional example, the response of the refrigeration cycle to the change in the opening of the expansion valve is insensitive, so the expansion valve is excessively throttled, and the cycle change becomes large.

On the other hand, in the present embodiment, the opening change of the electronic expansion valve starts earlier than in the conventional example, the opening change width of the electronic expansion valve is small, and the expansion valve is prevented from being excessively throttled. .

FIG. 9 is a graph showing changes in the degree of discharge gas superheat in the air conditioner shown in FIG. 1 and the conventional example. From this graph, it can be seen that the air conditioner of this example approaches the target discharge gas superheat degree more quickly.

Further, during the transient operation, the conventional proportional control has a problem in that when the degree of superheat sharply rises, the opening speed of the expansion valve opening does not follow so that the degree of superheat increases too much. However, according to the air conditioner of the present embodiment, since it is possible to determine the change width of the expansion valve opening from the response of the refrigeration cycle and change the opening, it is possible to suppress a rapid increase in the degree of superheat. it can.

[0051]

As described above, according to the present invention, a change in the superheat degree of the compressor discharge gas or a change in the temperature of the compressor discharge gas when the opening degree of the electronic expansion valve is changed by a predetermined value is detected. , It is determined whether the amount of refrigerant in the refrigeration cycle is appropriate based on the change in superheat detected by this detection means or the change in temperature of the compressor discharge gas. By controlling, even if the amount of the refrigerant in the entire refrigeration cycle is in a state other than a predetermined value, it is possible to provide an air conditioner that can optimize the refrigeration cycle temperature.

[Brief description of drawings]

FIG. 1 is a refrigeration cycle system diagram showing an air conditioner according to an embodiment of the present invention.

FIG. 2 is a graph showing a change in a discharge gas superheat degree with respect to a change in an expansion valve opening degree in the air conditioner shown in FIG.

3 is a graph showing the number of pulses for increasing / decreasing the expansion valve opening with respect to changes in the discharge gas superheat in the air conditioner shown in FIG.

4 is a flowchart showing an example of an operation for controlling the opening degree of an electronic expansion valve in the air conditioner shown in FIG.

5 is a graph showing a relationship between a condensing temperature and a target discharge gas superheat degree in the air conditioner shown in FIG.

FIG. 6 is a refrigeration cycle system diagram showing a flow of refrigerant during cooling in the air conditioner shown in FIG. 1.

FIG. 7 is a Mollier diagram of the refrigeration cycle shown in FIG.

FIG. 8 is a graph showing an opening control state of an electronic expansion valve in the air conditioner shown in FIG. 1 and a conventional example.

9 is a graph showing a transition of a discharge gas superheat degree in the air conditioner shown in FIG. 1 and a conventional example.

[Explanation of symbols]

 1 outdoor unit 2 compressor 3 four-way valve 4 outdoor heat exchanger 5 accumulator 6 connecting liquid pipe 7 connecting gas pipe 8 indoor unit 9 indoor heat exchanger 10 electronic expansion valve 11 outdoor control device 12 indoor control device 13 pressure sensor 14 Discharge gas temperature sensor 15 Indoor gas pipe temperature sensor 16 Indoor liquid pipe temperature sensor 17 Outdoor gas pipe temperature sensor 18 Outdoor liquid pipe temperature sensor

Claims (6)

[Claims] 1. An air conditioner in which a compressor, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger and an accumulator are sequentially connected to form a refrigeration cycle, and the opening degree of the electronic expansion valve is changed by a predetermined value. A detection means for detecting a change in the superheat degree of the compressor discharge gas at the time, and a judging means for judging whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in the superheat degree detected by the detection means. An air conditioner characterized by having. 2. The air conditioner according to claim 1, wherein the determining means determines that an appropriate amount of refrigerant is enclosed when the change range of the degree of superheat detected by the detecting means is in a predetermined region, When the change width of the superheat degree is less than the predetermined region,
When it is determined that the refrigerant is excessively sealed during the refrigeration cycle, and the variation range of the superheat degree exceeds the predetermined region, it is determined that the refrigerant in the refrigeration cycle is in a shortage state. An air conditioner having electronic expansion valve opening control means for adjusting a degree of opening change of the electronic expansion valve according to a result of the determination made by the determination means. 3. In an air conditioner in which a compressor, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger and an accumulator are sequentially connected to form a refrigeration cycle, the opening degree of the electronic expansion valve is changed by a predetermined value. Detecting means for detecting the temperature change of the compressor discharge gas when the temperature is changed, and it is judged whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the temperature change of the compressor discharge gas detected by the detecting means. An air conditioner having a determining means. 4. An air conditioner in which a compressor, an outdoor heat exchanger, an electronic expansion valve, an indoor heat exchanger and an accumulator are sequentially connected to form a refrigeration cycle, and the opening degree of the electronic expansion valve is changed by a predetermined value. First detection means for detecting a difference in inlet / outlet temperature of the indoor heat exchanger when the temperature is set, and a difference in inlet / outlet temperature of the outdoor heat exchanger when the opening degree of the electronic expansion valve is changed by a predetermined value. Second cooling means, and in the case of cooling operation, it is determined whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in superheat detected by the first detection means,
In the heating operation, the air conditioner is characterized by having a determination means for determining whether or not the amount of refrigerant in the refrigeration cycle is appropriate based on the change in superheat detected by the second detection means. 5. The air conditioner according to claim 3 or 4, wherein when the judging means judges that the amount of refrigerant in the refrigeration cycle is not appropriate, the electronic expansion valve changes the adjustment change width of the opening degree of the electronic expansion valve. An air conditioner having a valve opening control means. 6. The air conditioner according to claim 1, 2, 3, 4 or 5, wherein an electronic expansion valve opening for changing a PID control constant for controlling the opening degree of the electronic expansion valve according to the judgment result of the judgment means. An air conditioner having a degree control means.