JP2006234239A - Accumulator liquid refrigerant detecting method for air conditioning system, receiver liquid refrigerant detecting method, refrigerant amount adjusting method and air conditioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an accumulator liquid refrigerant detecting method for an air conditioning system, a receiver liquid refrigerant detecting method, a refrigerant amount adjusting method, and the air conditioning system. <P>SOLUTION: In a refrigerant circuit having a compressor 3, an outdoor heat exchanger 4, a receiver 11, a cooling expansion valve 5a, and an indoor heat exchanger 6, there are provided a bypass flow path 12 which takes refrigerant out of the bottom of the receiver 11 and supplies it to the upstream side of the compressor 3, a supercooling expansion valve 13 which expands the refrigerant supplied to the bypass flow path 12, and a suprecooling heat exchanger 14 which supercools the refrigerant to be fed from the receiver 11 to the cooling expansion valve 5a while heat-exchanging it with the refrigerant expanded by the supercooling expansion valve 13. Additional refrigerant is supplied to the refrigerant circuit while controlling the opening of the supercooling expansion valve 13 so that the degree of overheating the refrigerant passing through the indoor heat exchanger 6 gets to a preset value, and the existence of the liquid refrigerant in the receiver 11 is determined at the time when there is no change in the opening of the supercooling expansion valve 13. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an accumulator liquid refrigerant detection method, a receiver liquid refrigerant detection method, a refrigerant amount adjustment method, and an air conditioner for an air conditioner.

The air conditioner heats the refrigerant that has passed through the expansion valve, the compressor that compresses the refrigerant, the condenser that cools and liquefies the refrigerant that is sent out by the compressor, the expansion valve that expands the refrigerant that has passed through the condenser, and And an evaporator to be vaporized.
In the air conditioner, by circulating the refrigerant in the refrigerant circuit, heat exchange is performed between the ambient atmosphere of the condenser and the refrigerant and between the ambient atmosphere of the evaporator and the refrigerant. The temperature of either one is adjusted.

In an air conditioner, the amount of refrigerant that is vaporized by the evaporator varies depending on operating conditions and environmental conditions such as ambient temperature, so if the amount of refrigerant in the refrigerant circuit is small, depending on the operating conditions and environmental conditions, As a result, a shortage of refrigerant occurs and efficiency decreases. For this reason, in a general air conditioning apparatus, a configuration for temporarily storing excess refrigerant in the refrigerant circuit is provided so that refrigerant shortage does not occur in the refrigerant circuit even when operating conditions and environmental conditions fluctuate. .
As a configuration for temporarily storing surplus refrigerant, for example, an accumulator that temporarily stores the refrigerant that has passed through the evaporator, a refrigerant that has passed through the condenser, or a refrigerant that has passed through the evaporator is temporarily stored. There are receivers.

On the other hand, if the amount of refrigerant in the refrigerant circuit is too large, the condensation pressure of the refrigerant increases and the burden on the compressor increases, so the refrigerant in the refrigerant circuit is within an appropriate range, for example, to achieve high-efficiency operation. Therefore, it is desirable to make the minimum required amount under the assumed operating conditions.
As a method for detecting the amount of refrigerant in the refrigerant circuit, for example, there is a method described in Patent Document 1 described later.
In the method described in Patent Document 1, a liquid receiver for storing surplus refrigerant in a refrigeration cycle (refrigerant circuit) is provided with a liquid receiver liquid level detection pipe that communicates with the inside of the container. Connecting the piping for low pressure to the low pressure side piping of the refrigeration cycle via the pressure reducing means, detecting the temperature of the refrigerant decompressed by the pressure reducing means and the refrigerant temperature of the low pressure side piping of the refrigeration cycle, and based on this information We are looking for the situation of excess or deficiency.

JP-A-6-101941 (paragraphs [0009] to [0010] and FIG. 1)

However, even if only the gaseous refrigerant is supplied to the decompression means, depending on the configuration of the refrigerant circuit of the air conditioner, operating conditions, environmental conditions, etc., the temperature of the refrigerant decompressed by the decompression means and the low-pressure side piping of the refrigeration cycle The refrigerant temperature may not match. Moreover, the pressure of the refrigerant decompressed by the decompression means may be different from the refrigerant pressure in the low-pressure side piping of the refrigeration cycle. For this reason, it is not possible to accurately determine the excess or deficiency state of the refrigerant amount by simply comparing the refrigerant pressure reduced by the decompression means and the refrigerant temperature of the low-pressure side pipe of the refrigeration cycle.
Furthermore, since the air conditioner to which this method is applied is provided with the receiver liquid level detection pipe in the refrigerant circuit, the pipe structure is complicated and the manufacturing cost is high. In addition, when this method is applied to an existing air conditioner, it is necessary to add a pipe to the refrigerant circuit so that a pipe for detecting the liquid level of the liquid receiver is provided in the refrigerant circuit.

  The present invention has been made in view of such circumstances, and it is possible to accurately detect the amount of liquid refrigerant in an accumulator at a low cost, and in the receiver at a low cost in an accumulator. Method for detecting the amount of refrigerant in the receiver of an air conditioner capable of accurately detecting the amount of refrigerant in the air, a method for adjusting the amount of refrigerant capable of setting the amount of refrigerant to an appropriate amount at low cost, and automatically adjusting the amount of refrigerant An object is to provide an air conditioner.

In order to solve the above-described problems, an accumulator liquid refrigerant detection method, a receiver liquid refrigerant detection method, a refrigerant amount adjustment method, and an air conditioner of the present invention employ the following means.
That is, an accumulator liquid refrigerant detection method for an air conditioner according to the present invention includes a compressor that compresses a refrigerant, a condenser that cools and liquefies the refrigerant that is sent out by the compressor, and a refrigerant that has passed through the condenser A refrigerant circuit having an expansion valve that expands the refrigerant, an evaporator that heats and vaporizes the refrigerant that has passed through the expansion valve, and an accumulator that temporarily stores the refrigerant that is supplied from the evaporator to the compressor. For the air conditioner configured to connect the bottom of the accumulator and the upstream portion of the compressor and supply the liquid in the accumulator to the compressor, the liquid return channel A return liquid temperature measuring device for measuring the temperature of the liquid passing therethrough, and a low pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor; Based on the measured value of the low-pressure side pressure measuring device, the degree of superheat of the liquid flowing through the liquid return channel is detected, and all the liquid refrigerant is discharged from the accumulator when the degree of superheat is generated in the liquid. It is characterized by determining that it was.

In the air conditioner, when the operation is stopped, a part of the refrigerant evaporated by the evaporator in the refrigerant circuit during the operation is liquefied and stored in the accumulator. The liquid refrigerant in the accumulator gradually evaporates and decreases by restarting the operation of the air conditioner and restarting the superheat degree operation of the evaporator.
Since the liquid refrigerant in the accumulator has almost no degree of superheat, the liquid in the liquid return flow path has little degree of superheat when the liquid refrigerant exists in the accumulator.
On the other hand, when all of the liquid refrigerant in the accumulator is discharged, the gas refrigerant in the accumulator has a degree of superheat, so that the liquid in the liquid return channel also has a degree of superheat.

The method for detecting liquid refrigerant in the accumulator of the air conditioner according to the present invention uses this fact to detect the presence or absence of liquid refrigerant in the accumulator.
Specifically, based on the temperature of the liquid in the liquid return channel obtained by the return liquid temperature measurement device and the pressure of the refrigerant supplied to the compressor obtained by the low pressure side refrigerant pressure measurement device, The degree of superheat of the liquid in the liquid return channel is obtained, and when the degree of superheat does not occur in the liquid in the liquid return channel, it is determined that the liquid refrigerant is stored in the accumulator, When the liquid has a superheat degree, it is determined that all the liquid refrigerant has been discharged from the accumulator.
In this method for detecting liquid refrigerant in the accumulator of the air conditioner, the discharge of the liquid refrigerant in the accumulator can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner provided with the return liquid temperature measuring device and the low pressure side refrigerant pressure measuring device for operation control.

  In addition, the method for detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a compressor that compresses the refrigerant, and an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with the outside air. A receiver that temporarily stores the refrigerant that has passed through the outdoor heat exchanger, a cooling expansion valve that expands the refrigerant that has passed through the receiver, and heat exchange between the refrigerant that has passed through the cooling expansion valve and the indoor atmosphere. A bypass circuit for extracting a part of the refrigerant in the receiver from the bottom of the receiver and supplying it to the upstream side of the compressor in a refrigerant circuit having an indoor heat exchanger heated and vaporized by A supercooling expansion valve that expands the refrigerant supplied to the passage and a refrigerant sent from the receiver to the cooling expansion valve are supercooled by heat exchange with the refrigerant expanded by the supercooling expansion valve. An air conditioner configured to include a cooling heat exchanger, an indoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the indoor heat exchanger, and a pressure of the refrigerant that is supplied to the compressor A low pressure side refrigerant pressure measuring device, and during the cooling operation of the air conditioner, the indoor heat exchanger is controlled based on the measured value of the indoor side refrigerant temperature measuring device and the measured value of the low pressure side refrigerant pressure measuring device. The degree of superheat of the refrigerant that has passed is detected, and the refrigerant is added to the refrigerant circuit while controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value. It is determined that liquid refrigerant is present in the receiver at the time when the change in the opening of the valve stops occurring.

In the air conditioner, the refrigerant liquefied by the outdoor heat exchanger is expanded by the cooling expansion valve to become a low-temperature and low-pressure refrigerant, and the indoor heat exchanger performs heat exchange between the low-temperature and low-pressure refrigerant and the indoor atmosphere. As a result, the indoor atmosphere is cooled.
Here, the refrigerant liquefied by the outdoor heat exchanger is temporarily stored in the receiver, and a part thereof is taken out to the bypass channel. Here, since the bypass channel takes out the refrigerant from the bottom of the receiver, the liquid refrigerant always circulates in the bypass channel when there is a liquid refrigerant in the receiver.
The refrigerant taken out to the bypass channel is expanded by the supercooling expansion valve to become a low-temperature and low-pressure refrigerant, and the supercooling heat exchanger and the high-pressure liquid refrigerant and heat supplied from the receiver to the cooling expansion valve. It is exchanged and contributes to the supercooling of this high-pressure liquid refrigerant.

  During the cooling operation of this air conditioner, when there is liquid refrigerant in the receiver, liquid refrigerant is sufficiently supplied to the bypass flow path, so that the opening degree of the supercooling expansion valve is not so large Thus, the supercooling by the supercooling heat exchanger is sufficiently performed, and the refrigerant that has passed through the indoor heat exchanger can have a predetermined degree of superheating.

On the other hand, in the state where there is no liquid refrigerant in the receiver, liquid refrigerant is not sufficiently supplied to the bypass channel, and flashing occurs and the refrigerant flow rate is insufficient. In order to give the refrigerant having passed through the indoor heat exchanger a predetermined degree of superheat, the degree of opening of the supercooling expansion valve must be increased.
In other words, when the opening degree of the supercooling expansion valve is controlled so that the refrigerant that has passed through the indoor heat exchanger has a predetermined degree of superheat, in the state where there is liquid refrigerant in the receiver and in the state where there is no liquid refrigerant, There is a clear difference in the opening of the supercooling expansion valve.

The method for detecting the liquid refrigerant in the receiver of the air conditioner according to the present invention detects the presence or absence of the liquid refrigerant in the receiver using this fact.
Specifically, during the cooling operation of the air conditioner, the refrigerant is added to the refrigerant circuit while controlling the opening degree of the supercooling expansion valve as described above.
When the opening degree of the supercooling expansion valve decreases by adding the refrigerant in this way, it is determined that there is no liquid refrigerant in the receiver, and the opening degree of the supercooling expansion valve is clear even if the refrigerant is added. If no change occurs, it is determined that there is liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the indoor-side refrigerant temperature measuring device and the low-pressure side refrigerant pressure measuring device for operation control.
In addition, the receiver internal liquid refrigerant detection method of this air conditioning apparatus is applied when the refrigerant in the refrigerant circuit is deficient in an appropriate amount.

  A method for detecting liquid refrigerant in a receiver of an air conditioner according to the present invention includes a compressor that compresses a refrigerant, an indoor heat exchanger that cools and liquefies the refrigerant that is sent out by the compressor by heat exchange with an indoor atmosphere, A receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger, a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and the refrigerant that has passed through the heating expansion valve is heated by outside air. An outdoor air conditioner that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger is supplied to an air conditioner that includes a refrigerant circuit having an outdoor heat exchanger that is heated and vaporized by exchange, and is supplied to the compressor A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant to be measured, and during the heating operation of the air conditioner, the measured value of the outdoor refrigerant temperature measuring device and the measured value of the low-pressure side refrigerant pressure measuring device Base Detecting the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger, and adding the refrigerant to the refrigerant circuit while controlling the opening of the heating expansion valve so that the degree of superheat becomes a predetermined value. It is determined that liquid refrigerant is present in the receiver when the opening of the heating expansion valve no longer changes.

In the air conditioner, the refrigerant vaporized by the outdoor heat exchanger is heated by being compressed by the compressor and becomes a high-temperature and high-pressure gas refrigerant. The indoor heat exchanger uses the high-temperature and high-pressure gas refrigerant and the indoor atmosphere. The indoor atmosphere is heated by performing the heat exchange.
The refrigerant liquefied by the indoor heat exchanger is temporarily stored in the receiver, then expanded by the heating expansion valve to become a low-temperature and low-pressure refrigerant, and is further heat-exchanged with the outside air by the outdoor heat exchanger. Is vaporized and sent back to the compressor.

  Here, since the refrigerant taken out from the bottom of the receiver is sent to the heating expansion valve, when the air conditioner is in the heating operation, when the liquid refrigerant is present in the receiver, the liquid refrigerant is present in the heating expansion valve. Fully supplied. For this reason, by setting the opening degree of the heating expansion valve to a constant opening degree that is not so large, the superheat degree operation of the outdoor heat exchanger is sufficiently performed, and the refrigerant that has passed through the outdoor heat exchanger has a predetermined superheat. Can have a degree.

On the other hand, when there is no liquid refrigerant in the receiver, the heating expansion valve is not sufficiently supplied with liquid refrigerant, and flashing occurs, resulting in insufficient refrigerant flow. Therefore, in order to give the refrigerant having passed through the outdoor heat exchanger a predetermined degree of superheat, the opening of the heating expansion valve must be increased.
In other words, when the opening of the heating expansion valve is controlled so that the refrigerant that has passed through the outdoor heat exchanger has a predetermined degree of superheat, heating is performed in a state where there is liquid refrigerant in the receiver and in a state where there is no liquid refrigerant. There is a clear difference in the opening of the expansion valve.

The method for detecting the liquid refrigerant in the receiver of the air conditioner according to the present invention detects the presence or absence of the liquid refrigerant in the receiver using this fact.
Specifically, during the heating operation of the air conditioner, the refrigerant is added to the refrigerant circuit while controlling the opening degree of the heating expansion valve as described above.
When the opening of the heating expansion valve is reduced by adding the refrigerant in this way, it is determined that there is no liquid refrigerant in the receiver, and even if the refrigerant is added, the opening of the heating expansion valve is clearly changed. If no occurs, it is determined that there is liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the outdoor refrigerant temperature measuring device and the low-pressure refrigerant pressure measuring device for operation control.
In addition, the receiver internal liquid refrigerant detection method of this air conditioning apparatus is applied when the refrigerant in the refrigerant circuit is deficient in an appropriate amount. Here, when the opening degree of the heating expansion valve is larger than the normally used range, or when the opening degree of the heating expansion valve becomes small when the refrigerant is actually added to the refrigerant circuit, the refrigerant circuit The refrigerant in the receiver can be regarded as insufficient, and the liquid refrigerant detection method in the receiver of the air conditioner can be applied.

  Moreover, the method of detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a compressor that compresses the refrigerant, and an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with the indoor atmosphere. A receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger, a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and a refrigerant that has passed through the heating expansion valve A bypass circuit for supplying a part of the refrigerant that has passed through the indoor heat exchanger to the upstream side of the compressor, and a bypass flow path in a refrigerant circuit having an outdoor heat exchanger that is heated and vaporized by heat exchange of A supercooling expansion valve for expanding the refrigerant supplied to the passage, and a supercooling for cooling the refrigerant sent from the indoor heat exchanger to the receiver by heat exchange with the refrigerant expanded by the subcooling expansion valve heat A low-temperature side that measures the pressure of refrigerant supplied to the compressor, and an outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger. A refrigerant pressure measuring device, and during the heating operation of the air conditioner, the outdoor heat exchanger passed through the measured value of the outdoor refrigerant temperature measuring device and the measured value of the low pressure refrigerant pressure measuring device The refrigerant is added to the refrigerant circuit while detecting the degree of superheat of the refrigerant and controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value. It is determined that liquid refrigerant is present in the receiver at the time when the change in the opening degree stops occurring.

In the air conditioner, the refrigerant vaporized by the outdoor heat exchanger is heated by being compressed by the compressor and becomes a high-temperature and high-pressure gas refrigerant. The indoor heat exchanger uses the high-temperature and high-pressure gas refrigerant and the indoor atmosphere. The indoor atmosphere is heated by performing the heat exchange.
The refrigerant liquefied by the indoor heat exchanger is temporarily stored in the receiver, then expanded by the heating expansion valve to become a low-temperature and low-pressure refrigerant, and is further heat-exchanged with the outside air by the outdoor heat exchanger. Is vaporized and sent back to the compressor.

Here, since the refrigerant taken out from the bottom of the receiver is fed into the heating expansion valve, the liquid refrigerant is always circulated through the heating expansion valve in a state where there is liquid refrigerant in the receiver.
The refrigerant taken out to the bypass flow path is expanded by a supercooling expansion valve to become a low-temperature and low-pressure refrigerant, and is supplied from the indoor heat exchanger to the receiver by the supercooling heat exchanger. Heat exchange, and contributes to the supercooling of the high-pressure liquid refrigerant.

  During heating operation of this air conditioner, in the state where there is liquid refrigerant in the receiver, liquid refrigerant is sufficiently supplied to the heating expansion valve, so that the superheat operation of the outdoor heat exchanger is sufficiently performed, The refrigerant having passed through the outdoor heat exchanger can have a predetermined degree of superheat. That is, in the state where there is a liquid refrigerant in the receiver, it is not necessary to supercool the refrigerant so much, so that the degree of opening of the supercooling expansion valve is set to a certain degree of opening so that it passes through the outdoor heat exchanger. The refrigerant can have a predetermined degree of superheat.

On the other hand, when there is no liquid refrigerant in the receiver, the heating expansion valve is not sufficiently supplied with liquid refrigerant, and flashing occurs, resulting in insufficient refrigerant flow. Therefore, in order to give the refrigerant having passed the outdoor heat exchanger a predetermined degree of superheat, it is necessary to increase the degree of opening of the supercooling expansion valve so that the refrigerant sent to the receiver has a higher degree of supercooling. There is.
That is, when the opening degree of the supercooling expansion valve is controlled so that the refrigerant that has passed through the outdoor heat exchanger has a predetermined degree of superheat, in the state where there is liquid refrigerant in the receiver and in the state where there is no liquid refrigerant, There is a clear difference in the opening of the supercooling expansion valve.

The method for detecting the liquid refrigerant in the receiver of the air conditioner according to the present invention detects the presence or absence of the liquid refrigerant in the receiver using this fact.
Specifically, during the heating operation of the air conditioner, the refrigerant is added to the refrigerant circuit while controlling the opening degree of the supercooling expansion valve as described above.
When the opening degree of the supercooling expansion valve decreases by adding the refrigerant in this way, it is determined that there is no liquid refrigerant in the receiver, and the opening degree of the supercooling expansion valve is clear even if the refrigerant is added. If no change occurs, it is determined that there is liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the outdoor refrigerant temperature measuring device and the low-pressure refrigerant pressure measuring device for operation control.
In addition, the receiver internal liquid refrigerant detection method of this air conditioning apparatus is applied when the refrigerant in the refrigerant circuit is deficient in an appropriate amount. Here, when the opening degree of the expansion valve for supercooling is larger than the range normally used, or when the opening degree of the expansion valve for supercooling becomes small when the refrigerant is actually added to the refrigerant circuit, It can be considered that the refrigerant in the refrigerant circuit is insufficient, and the receiver liquid refrigerant detection method of the air conditioner can be applied.

  In addition, the method for detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a compressor that compresses the refrigerant, and an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with the outside air. A receiver that temporarily stores the refrigerant that has passed through the outdoor heat exchanger, a cooling expansion valve that expands the refrigerant that has passed through the receiver, and heat exchange between the refrigerant that has passed through the cooling expansion valve and the indoor atmosphere. A bypass circuit for extracting a part of the refrigerant in the receiver from the bottom of the receiver and supplying it to the upstream side of the compressor in a refrigerant circuit having an indoor heat exchanger heated and vaporized by A supercooling expansion valve that expands the refrigerant supplied to the passage and a refrigerant sent from the receiver to the cooling expansion valve are supercooled by heat exchange with the refrigerant expanded by the supercooling expansion valve. An air conditioner configured to include a cooling heat exchanger, an indoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the indoor heat exchanger, and a pressure of the refrigerant that is supplied to the compressor A low pressure side refrigerant pressure measuring device, and during the cooling operation of the air conditioner, the indoor heat exchanger is controlled based on the measured value of the indoor side refrigerant temperature measuring device and the measured value of the low pressure side refrigerant pressure measuring device. The degree of superheat of the refrigerant that has passed is detected, the refrigerant is taken out from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value, and the expansion for supercooling is performed. It is characterized in that it is determined that the liquid refrigerant in the receiver is exhausted when the change in the valve opening occurs.

The method for detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a method in which the opening of the expansion valve for supercooling is controlled so that the refrigerant that has passed through the indoor heat exchanger has a predetermined degree of superheat. The presence or absence of liquid refrigerant in the receiver is detected by utilizing a clear difference between the opening degree of the supercooling expansion valve between the state with liquid refrigerant and the state without liquid refrigerant.
Specifically, during the cooling operation of the air conditioner, a part of the refrigerant is taken out from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve as described above.
If no clear change occurs in the opening degree of the supercooling expansion valve even if the refrigerant is taken out in this way, it is determined that there is liquid refrigerant in the receiver, and the supercooling expansion valve is removed by taking out the refrigerant. When the opening degree increases, it is determined that there is no liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the outdoor refrigerant temperature measuring device and the low-pressure refrigerant pressure measuring device for operation control.
Note that the receiver liquid refrigerant detection method of the air conditioner is applied when the refrigerant in the refrigerant circuit is more than an appropriate amount. Here, when the opening degree of the expansion valve for supercooling is within the normal use range or below, or when the opening degree of the expansion valve for supercooling does not change when the refrigerant is actually taken out to the refrigerant circuit It can be considered that the refrigerant in the refrigerant circuit is more than an appropriate amount, and the liquid refrigerant detection method in the receiver of the air conditioner can be applied.

  Moreover, the method of detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a compressor that compresses the refrigerant, and an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with the indoor atmosphere. A receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger, a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and a refrigerant that has passed through the heating expansion valve An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger, an air conditioner that includes an outdoor heat exchanger that is heated and vaporized by heat exchange of the outdoor heat exchanger, and the compressor A low-pressure-side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the air-conditioner, and during the heating operation of the air-conditioning apparatus, the measured value of the outdoor-side refrigerant temperature measuring device and the measurement of the low-pressure-side refrigerant pressure measuring device value Based on this, the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger is detected, and the refrigerant is taken out from the refrigerant circuit while controlling the opening of the heating expansion valve so that the degree of superheat becomes a predetermined value. And determining that the liquid refrigerant in the receiver is exhausted when a change in the opening degree of the heating expansion valve occurs.

In the method for detecting liquid refrigerant in the receiver of the air conditioner according to the present invention, when the opening degree of the expansion valve for heating is controlled so that the refrigerant having passed through the outdoor heat exchanger has a predetermined degree of superheat, The presence or absence of liquid refrigerant in the receiver is detected by utilizing the fact that there is a clear difference in the opening of the heating expansion valve between the state where there is a refrigerant and the state where there is no liquid refrigerant.
Specifically, during the heating operation of the air conditioner, a part of the refrigerant is taken out from the refrigerant circuit while controlling the opening degree of the heating expansion valve as described above.
If the opening of the heating expansion valve does not clearly change even after the refrigerant is taken out in this way, it is determined that there is liquid refrigerant in the receiver, and the opening of the heating expansion valve increases by removing the refrigerant. If so, it is determined that there is no liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the outdoor refrigerant temperature measuring device and the low-pressure refrigerant pressure measuring device for operation control.
Note that the receiver liquid refrigerant detection method of the air conditioner is applied when the refrigerant in the refrigerant circuit is more than an appropriate amount.

  Moreover, the method of detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a compressor that compresses the refrigerant, and an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with the indoor atmosphere. A receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger, a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and a refrigerant that has passed through the heating expansion valve A bypass circuit for supplying a part of the refrigerant that has passed through the indoor heat exchanger to the upstream side of the compressor, and a bypass flow path in a refrigerant circuit having an outdoor heat exchanger that is heated and vaporized by heat exchange of A supercooling expansion valve for expanding the refrigerant supplied to the passage, and a supercooling for cooling the refrigerant sent from the indoor heat exchanger to the receiver by heat exchange with the refrigerant expanded by the subcooling expansion valve heat A low-temperature side that measures the pressure of refrigerant supplied to the compressor, and an outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger. A refrigerant pressure measuring device, and during the heating operation of the air conditioner, the outdoor heat exchanger passed through the measured value of the outdoor refrigerant temperature measuring device and the measured value of the low pressure refrigerant pressure measuring device The degree of superheat of the refrigerant is detected, and the refrigerant is taken out from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value. It is characterized in that it is determined that the liquid refrigerant in the receiver is exhausted when the change in the opening degree occurs.

The method for detecting the refrigerant in the receiver of the air conditioner according to the present invention includes a method in which the opening of the expansion valve for supercooling is controlled so that the refrigerant that has passed through the outdoor heat exchanger has a predetermined degree of superheat. The presence or absence of liquid refrigerant in the receiver is detected by utilizing a clear difference between the opening degree of the supercooling expansion valve between the state with liquid refrigerant and the state without liquid refrigerant.
Specifically, during the heating operation of the air conditioner, a part of the refrigerant is taken out from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve as described above.
In this way, when there is no clear change in the opening degree of the supercooling expansion valve even if the refrigerant is taken out, it is determined that there is liquid refrigerant in the receiver, and the opening degree of the supercooling expansion valve is taken out by taking out the refrigerant. Is increased, it is determined that there is no liquid refrigerant in the receiver.

With this method for detecting the liquid refrigerant in the receiver of the air conditioner, the presence or absence of the liquid refrigerant in the receiver can be accurately confirmed with almost no modification to the conventional air conditioner. In particular, it is not necessary to modify the air conditioner that includes the outdoor refrigerant temperature measuring device and the low-pressure refrigerant pressure measuring device for operation control.
Note that the receiver liquid refrigerant detection method of the air conditioner is applied when the refrigerant in the refrigerant circuit is more than an appropriate amount.

  The method for adjusting the amount of refrigerant in an air conditioner according to the present invention uses the method for detecting liquid refrigerant in a receiver of an air conditioner that is performed while adding the above-described refrigerant while determining the presence or absence of liquid refrigerant in the receiver. The refrigerant is gradually added to the refrigerant circuit, and the addition of the refrigerant is stopped when the liquid refrigerant in the receiver is detected.

  In this method of adjusting the amount of refrigerant in the air conditioner, the receiver's liquid refrigerant detection method for the air conditioner that is performed while adding the above-mentioned refrigerant accurately confirms the presence or absence of the liquid refrigerant in the receiver. Since the addition of the refrigerant to the refrigerant circuit is stopped when the liquid refrigerant is detected, the amount of refrigerant in the refrigerant circuit can be minimized and the operation efficiency can be improved.

  The refrigerant amount adjusting method for an air conditioner according to the present invention is a method for determining the presence or absence of liquid refrigerant in the receiver by using the receiver liquid refrigerant detection method of the air conditioner that is performed while taking out the refrigerant. The refrigerant in the circuit is taken out step by step by a certain amount, and when it is determined that the liquid refrigerant in the receiver has run out, the refrigerant is stopped from being taken out, and a predetermined amount less than the single take-out amount of the refrigerant is obtained. The adjustment is completed by adding the refrigerant to the refrigerant circuit.

In the method of detecting refrigerant in the receiver of the air conditioner that is performed while taking out the refrigerant, the refrigerant in the refrigerant circuit is taken out step by step in a certain amount, and this is detected when the liquid refrigerant in the receiver runs out. .
That is, when the refrigerant is taken out from the refrigerant circuit and it is detected that the liquid refrigerant in the receiver is exhausted, the refrigerant in the refrigerant circuit is slightly less than the minimum necessary amount (this shortage). The amount is less than a single removal amount). Therefore, at this point in time, the removal of the refrigerant is stopped, and a predetermined amount of refrigerant that is less than a single removal amount is added to the refrigerant circuit, so that the amount of refrigerant in the refrigerant circuit is almost the minimum necessary amount. be able to.

  The refrigerant amount adjustment method for an air conditioner according to the present invention includes an air conditioner in which an accumulator and a receiver are provided in a refrigerant circuit, and a method for detecting the amount of refrigerant in the accumulator of the air conditioner according to the present invention. The refrigerant amount in the refrigerant circuit is adjusted using the refrigerant amount adjustment method of the air conditioner according to the present invention. Features.

  In this method of adjusting the amount of refrigerant in the air conditioner, the amount of liquid refrigerant in the receiver is minimized with the excess refrigerant in the accumulator being eliminated, so that the air conditioner having an accumulator also has refrigerant in the refrigerant circuit. The amount can be minimized.

  An air conditioner according to the present invention has passed through a compressor that compresses refrigerant, an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with outside air, and the outdoor heat exchanger. A receiver that temporarily stores the refrigerant, a cooling expansion valve that expands the refrigerant that has passed through the receiver, and an indoor heat exchange that heats and vaporizes the refrigerant that has passed through the cooling expansion valve by heat exchange with the indoor atmosphere. A bypass passage that takes out a part of the refrigerant in the receiver from the bottom of the receiver and supplies it to the upstream side of the compressor, and an expansion valve for supercooling that expands the refrigerant supplied to the bypass passage And a supercooling heat exchanger that supercools the refrigerant sent from the receiver to the cooling expansion valve by heat exchange with the refrigerant expanded by the supercooling expansion valve, and the indoor heat exchange An indoor-side refrigerant temperature measurement device that measures the temperature of the refrigerant that has passed through, a low-pressure-side refrigerant pressure measurement device that measures the pressure of the refrigerant supplied to the compressor, and the upstream side of the compressor in the refrigerant circuit from the upstream side A refrigerant recovery device that recovers the refrigerant; a refrigerant supply device that supplies the refrigerant to the refrigerant circuit from an upstream side of the cooling expansion valve of the refrigerant circuit; the cooling expansion valve; the supercooling expansion valve; A control device for controlling the operation of the refrigerant recovery device and the refrigerant supply device based on the refrigerant amount adjustment method of the air conditioner according to the present invention to adjust the refrigerant amount in the refrigerant circuit during the cooling operation; It is provided.

  In the air conditioner configured as described above, the refrigerant amount in the refrigerant circuit during the cooling operation can be adjusted to an appropriate amount by using the refrigerant amount adjusting method of the air conditioner according to the present invention.

Here, the refrigerant recovery device includes, for example, a refrigerant recovery cylinder, a recovery-side connection pipe that connects the refrigerant recovery cylinder to the refrigerant circuit, a recovery-side automatic valve that opens and closes the recovery-side connection pipe and whose opening and closing is controlled by the control device. Can be configured. Note that the recovery side connection pipe may be provided with a flow rate adjusting device (for example, a capillary) for adjusting the flow rate of the refrigerant. Moreover, you may use the collection | recovery side electronic expansion valve which adjusts the refrigerant | coolant flow rate of collection | recovery side connection piping instead of a collection | recovery side automatic valve.
Similarly, the refrigerant supply device includes, for example, a refrigerant supply cylinder, a supply-side connection pipe that connects the refrigerant supply cylinder to the refrigerant circuit, a supply-side automatic valve that opens and closes the supply-side connection pipe and whose opening and closing is controlled by the control device. Can be configured. In addition, you may provide the flow control apparatus which adjusts the flow volume of a refrigerant | coolant in supply side connection piping. Moreover, you may use the supply side electronic expansion valve which adjusts the refrigerant | coolant flow rate of supply side connection piping instead of a supply side automatic valve.

  An air conditioner according to the present invention includes a compressor that compresses a refrigerant, an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere, and passes through the indoor heat exchanger. A receiver that temporarily stores the refrigerant, a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and the refrigerant that has passed through the heating expansion valve is heated and vaporized by heat exchange with outside air An outdoor heat exchanger, a bypass passage for supplying a part of the refrigerant that has passed through the indoor heat exchanger to the upstream side of the compressor, and an expansion valve for supercooling that expands the refrigerant supplied to the bypass passage And a supercooling heat exchanger that supercools the refrigerant sent from the indoor heat exchanger to the receiver by heat exchange with the refrigerant expanded by the supercooling expansion valve, and the outdoor heat exchange Pass through the vessel An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant, a low-pressure refrigerant pressure measuring device that measures the pressure of the refrigerant supplied to the compressor, and the refrigerant from the upstream side of the compressor in the refrigerant circuit. A refrigerant recovery device for recovery, a refrigerant supply device for supplying the refrigerant to the refrigerant circuit from an upstream side of the heating expansion valve of the refrigerant circuit, the heating expansion valve, the supercooling expansion valve, and the refrigerant recovery And a control device for adjusting the refrigerant amount in the refrigerant circuit during heating operation by controlling the operation of the refrigerant supply device based on the refrigerant amount adjustment method of the air conditioner according to the present invention. It is characterized by.

  In the air conditioner configured as described above, the refrigerant amount in the refrigerant circuit during the heating operation can be adjusted to an appropriate amount by using the refrigerant amount adjusting method of the air conditioner according to the present invention.

  Here, in each air conditioner according to the present invention, the refrigerant circuit connects an accumulator that temporarily stores the refrigerant supplied to the compressor, a bottom portion of the accumulator, and an upstream portion of the compressor A liquid return passage for supplying the liquid in the accumulator to the compressor, and a return liquid temperature measuring device for measuring the temperature of the liquid passing through the liquid return passage. Based on the measured value of the return liquid temperature measuring device and the measured value of the low pressure side pressure measuring device, the degree of superheat of the liquid flowing through the liquid return channel is detected, and when the degree of superheat has occurred in the liquid, the refrigerant circuit It may be configured to start adjustment of the amount of the refrigerant inside.

  In this case, since the liquid refrigerant in the receiver is minimized with the excess refrigerant in the accumulator being eliminated, the amount of refrigerant in the refrigerant circuit can be minimized.

  In each air conditioner according to the present invention, at least one of the refrigerant recovery device and the refrigerant supply device may be detachable from the refrigerant circuit.

In the air conditioner configured as described above, since at least one of the refrigerant recovery device and the refrigerant supply device can be removed from the refrigerant circuit except when necessary, the installation space of the air conditioner is reduced. can do.
Moreover, since at least any one of a refrigerant | coolant collection | recovery apparatus and a refrigerant | coolant supply apparatus can be shared between several air conditioning apparatuses, apparatus cost can be reduced.

According to the method for detecting liquid refrigerant in the accumulator of the air conditioner according to the present invention, the discharge of the liquid refrigerant in the accumulator can be confirmed accurately, and the conventional air conditioner is implemented with little modification. It can be done at no cost.

  According to the method for detecting liquid refrigerant in the receiver of the air conditioner according to the present invention, the presence or absence of liquid refrigerant in the receiver can be accurately confirmed, and the conventional air conditioner is implemented with little modification. It can be done at no cost.

  According to the refrigerant quantity adjustment method for an air conditioner according to the present invention, the refrigerant quantity in the refrigerant circuit can be adjusted to the minimum necessary at low cost, and the operation efficiency can be improved.

  According to the air conditioner of the present invention, the amount of refrigerant can be accurately and automatically adjusted within an appropriate range at a low cost.

Embodiments of an air conditioner according to the present invention will be described below with reference to the drawings.
[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 5.
The air conditioning apparatus 1 according to the present embodiment has a refrigerant circuit 2 having the configuration shown in FIG.
The refrigerant circuit 2 includes a compressor 3 that compresses and delivers a refrigerant on a refrigerant flow path through which the refrigerant is circulated, an outdoor heat exchanger 4 that exchanges heat between the refrigerant and outside air, and an electron that expands the refrigerant. The expansion valve 5 and the indoor heat exchanger 6 that performs heat exchange between the refrigerant and the room atmosphere are provided in this order, and the heating cycle and the cooling cycle are switched by switching the flow direction of the refrigerant. Or any one of them can be selectively formed.

A portion of the refrigerant circuit 2 where the compressor 3 is provided is connected to the other portion of the refrigerant circuit 2 via a four-way valve 7.
The four-way valve 7 controls the flow of refrigerant in the refrigerant circuit 2 by controlling the refrigerant discharge direction from the compressor 3 and the refrigerant supply direction to the compressor 3 in the refrigerant circuit 2, so that the heating cycle and the cooling cycle are performed. Are selectively formed.
Then, as will be described later, a cooling cycle is formed by sending the refrigerant from the compressor 3 toward the outdoor heat exchanger 4, and heating is performed by sending the refrigerant from the compressor 3 toward the indoor heat exchanger 6. A cycle is formed.

The refrigerant circuit 2 is provided with a cooling expansion valve 5a and a heating expansion valve 5b as the electronic expansion valve 5, and the air conditioner 1 has a configuration in which these electronic expansion valves 5 are selectively used according to the operation mode. Has been.
Specifically, the refrigerant circuit 2 is provided with a cooling passage 2b that bypasses the heating expansion valve 5b and a heating passage 2c that bypasses the cooling expansion valve 5a. The cooling passage 2b includes A check valve 8 is provided that allows a flow toward the indoor heat exchanger 6 and restricts a flow toward the outdoor heat exchanger 4, and the heating flow path 2c allows a flow toward the outdoor heat exchanger 4 to be indoors. A check valve 9 for restricting the flow toward the heat exchanger 6 is provided. Thus, only the cooling expansion valve 5a of the electronic expansion valve 5 is used when the cooling cycle is formed, and only the heating expansion valve 5b of the electronic expansion valve 5 is used when the heating cycle is formed.

  In the refrigerant circuit 2, the cooling expansion valve 5a is provided on the indoor heat exchanger 6 side, and the heating expansion valve 5b is provided on the outdoor heat exchanger 4 side. In the refrigerant circuit 2, a receiver 11 for temporarily storing refrigerant is provided between the cooling expansion valve 5a and the heating expansion valve 5b. The refrigerant flow path constituting the refrigerant circuit 2 is opened at the bottom of the receiver 11, and the refrigerant is sent to the downstream side of the receiver 11 in the refrigerant circuit 2 from the bottom of the receiver. That is, when there is a liquid refrigerant in the receiver 11, the liquid refrigerant is supplied to the downstream side of the receiver 11.

  Further, in the refrigerant circuit 2, a part of the refrigerant in the receiver 11 is extracted from the bottom of the receiver 11 and supplied to the upstream side of the compressor 3, and the refrigerant supplied to the bypass flow path 12 is expanded. And a supercooling heat exchanger 14 that supercools the refrigerant sent from the receiver 11 to the cooling expansion valve 5a by heat exchange with the refrigerant expanded by the supercooling expansion valve 13. It has been.

Further, the refrigerant circuit 2 is connected to an accumulator 16 for temporarily storing refrigerant supplied to the compressor 3, and a bottom portion of the accumulator 16 and an upstream portion of the compressor 3, so that liquid (mainly A liquid return passage 17 for supplying the lubricating oil discharged from the compressor 3) to the compressor 3 is provided. The liquid return channel 17 is provided with a decompression device 17a such as a capillary, and the liquid return speed from the accumulator 16 is appropriately adjusted.
The refrigerant circuit 2 is provided with an oil separator 18 that separates the lubricating oil from the refrigerant discharged from the compressor 3, and a lubricating oil return pipe 19 that returns the lubricating oil separated by the oil separator 18 to the compressor 3. ing.

  In addition, a refrigerant recovery device 21 that recovers the refrigerant in the refrigerant circuit 2 is connected to the refrigerant circuit 2 upstream of the compressor 3 (between the four-way valve 7 and the accumulator 16 in the present embodiment). A refrigerant supply device 22 for supplying a refrigerant into the refrigerant circuit 2 is connected between the cooling expansion valve 5a and the heating expansion valve 5b.

The refrigerant recovery device 21 includes a refrigerant recovery cylinder 21a, a recovery side connection pipe 21b that connects the refrigerant recovery cylinder 21a to the refrigerant circuit 2, a recovery side automatic valve 21c that opens and closes the recovery side connection pipe 21b, and a recovery side connection pipe 21b. And a flow rate adjusting device 21d such as a capillary for adjusting the flow rate of the refrigerant flowing through the inside. Instead of the recovery-side automatic valve 21 and the flow rate adjusting device 21d, a recovery-side electronic expansion valve that adjusts the refrigerant flow rate of the recovery-side connection pipe 21b may be provided.
The refrigerant supply device 22 includes a refrigerant supply cylinder 22a, a supply side connection pipe 22b that connects the refrigerant supply cylinder 22a to the refrigerant circuit 2, a supply side automatic valve 22c that opens and closes the supply side connection pipe 22b, and a supply side connection pipe 22b. And a flow rate adjusting device 22d such as a capillary for adjusting the flow rate of the refrigerant flowing through the inside. Instead of the supply-side automatic valve 22 and the flow rate adjusting device 22d, a supply-side electronic expansion valve that adjusts the refrigerant flow rate of the supply-side connection pipe 22b may be provided.

The refrigerant circuit 2 includes an indoor-side refrigerant temperature measuring device 23 that measures the temperature of the refrigerant at the outlet of the indoor heat exchanger 4 on the compressor 3 side, and a refrigerant at the outlet of the outdoor heat exchanger 4 on the compressor 3 side. The outdoor refrigerant temperature measuring device 24 that measures the temperature of the refrigerant, the low-pressure side refrigerant pressure measuring device 26 that measures the pressure of the refrigerant supplied to the compressor 3 in the refrigerant circuit 2, and the liquid that passes through the liquid return passage 17. And a return liquid temperature measuring device 27 for measuring the temperature of the liquid. In addition to this, the air conditioner 1 has various sensors for obtaining operation information, such as an indoor ambient temperature measuring device (not shown).
Furthermore, the air conditioner 1 is provided with a control device 28 that controls the operation of each component device of the air conditioner 1 based on the measurement results of these measurement devices.

  In the air conditioner 1, during the cooling operation, the four-way valve 7 is operated by the control device 28, and the gaseous refrigerant compressed by the compressor 3 is sent to the outdoor heat exchanger 4. The gaseous refrigerant sent to the outdoor heat exchanger 4 is liquefied by heat exchange with the outside air by the outdoor heat exchanger 4 and then temporarily stored in the receiver 11. The liquid refrigerant in the receiver 11 is supercooled by the supercooling heat exchanger 14 and then sent to the cooling expansion valve 5a to be expanded to become a low-temperature and low-pressure refrigerant. The low-temperature and low-pressure refrigerant exchanges heat with the indoor atmosphere by the indoor heat exchanger 6 and contributes to cooling of the indoor atmosphere, and then is sent to the accumulator 16 to be temporarily stored. The refrigerant stored in the accumulator 16 is sent again to the compressor 3 and used for the cooling operation.

  Here, a part of the refrigerant in the receiver 11 is taken out to the bypass channel 12. The refrigerant taken out to the bypass passage 12 is expanded by the supercooling expansion valve 13 to become a low-temperature and low-pressure refrigerant, and is supplied from the receiver 11 to the cooling expansion valve 5 a by the supercooling heat exchanger 14. Heat exchange with this liquid refrigerant contributes to the supercooling of this high-pressure liquid refrigerant.

  Further, in the air conditioner 1, during the heating operation, the four-way valve 7 is operated by the control device 28, and the high-temperature and high-pressure gaseous refrigerant compressed by the compressor 3 is sent to the indoor heat exchanger 6. The high-temperature and high-pressure gaseous refrigerant sent to the indoor heat exchanger 6 is heat-exchanged with the indoor atmosphere by the indoor heat exchanger 6 and contributes to heating of the indoor atmosphere and is liquefied. This liquid refrigerant is temporarily stored in the receiver 11 after being supercooled by the supercooling heat exchanger 14. The liquid refrigerant in the receiver 11 is expanded by the heating expansion valve 5b and becomes a low-temperature refrigerant. The low-temperature refrigerant is vaporized by heat exchange with the outside air by the outdoor heat exchanger 4 and then temporarily stored in the accumulator 16. The refrigerant stored in the accumulator 16 is sent again to the compressor 3 and used for heating operation.

  Here, a part of the refrigerant that has passed through the indoor heat exchanger 6 is taken out to the bypass passage 12. The refrigerant taken out to the bypass channel 12 is expanded by the supercooling expansion valve 13 to become a low-temperature and low-pressure refrigerant, and is cooled from the indoor heat exchanger 6 to the receiver 11 by the supercooling heat exchanger 14. Heat exchange with the high-pressure liquid refrigerant supplied to 5a contributes to the supercooling of the high-pressure liquid refrigerant.

During the operation of the air conditioner 1, the amount of refrigerant in the refrigerant circuit 2 is adjusted by the control device 28 so that the amount of refrigerant in the refrigerant circuit 2 is appropriate.
Specifically, the control device 28 monitors the liquid refrigerant (surplus refrigerant) in the accumulator 16 and the receiver 11, and based on this information, the liquid refrigerant (surplus refrigerant) in the accumulator 16 and the receiver 11 is detected. The operations of the refrigerant recovery device 21 and the refrigerant supply device 22 are controlled so that the refrigerant amount is almost eliminated and the refrigerant amount is not short.

Hereinafter, the detection principle of the liquid refrigerant in the accumulator 16 by the control device 28 will be described.
Since the liquid refrigerant in the accumulator 16 has almost no degree of superheat, when the liquid refrigerant exists in the accumulator 16, the liquid return flow path for returning the liquid in the accumulator 16 to the compressor 3 from the bottom of the accumulator 16. The liquid in 17 has little superheat.
On the other hand, when all of the liquid refrigerant in the accumulator 16 is discharged, the gas refrigerant in the accumulator 16 has a degree of superheat, so that the liquid in the liquid return channel 17 also has a degree of superheat. .
The control device 28 uses this fact to detect the presence or absence of the liquid refrigerant in the accumulator 16.

  Specifically, the temperature of the liquid in the liquid return channel 17 obtained by the return liquid temperature measuring device 27 and the pressure of the refrigerant supplied to the compressor 3 obtained by the low-pressure side refrigerant pressure measuring device 26. Based on the above, the degree of superheat of the liquid in the liquid return channel 17 is obtained, and when the degree of superheat does not occur in the liquid in the liquid return channel 17, it is determined that the liquid refrigerant is stored in the accumulator 16. When the liquid in the liquid return channel 17 has a superheat degree, it is determined that all the liquid refrigerant has been discharged from the accumulator 16.

Hereinafter, the detection principle of the liquid refrigerant in the receiver 11 by the control device 28 will be described.
During the cooling operation of the air conditioner 1, a part of the refrigerant in the receiver 11 is taken out from the bottom of the receiver 11 to the bypass channel 12 as described above.
In the state where the liquid refrigerant is present in the receiver 11, the liquid refrigerant is sufficiently supplied to the bypass flow path 12. Therefore, by setting the opening degree of the expansion valve 13 for supercooling to a certain degree of opening degree, the supercooling is performed. Subcooling is sufficiently performed by the heat exchanger 14, and the refrigerant that has passed through the indoor heat exchanger 6 can have a predetermined degree of superheat. Here, the degree of superheat of the refrigerant that has passed through the indoor heat exchanger 6 is obtained based on the measured value of the indoor refrigerant temperature measuring device 23 and the measured value of the low-pressure refrigerant pressure measuring device 26.

On the other hand, in the state where there is no liquid refrigerant in the receiver 11, liquid refrigerant is not sufficiently supplied to the bypass flow path 12, and flashing occurs and the refrigerant flow rate is insufficient. Therefore, the supercooling heat exchanger 14 is sufficiently cooled. In order to make the refrigerant having passed through the indoor heat exchanger 6 have a predetermined degree of superheat, the opening degree of the supercooling expansion valve 13 must be increased.
That is, when the opening degree of the supercooling expansion valve 13 is controlled so that the refrigerant that has passed through the indoor heat exchanger 6 has a predetermined degree of superheat, there are liquid refrigerant in the receiver 11 and no liquid refrigerant. Then, as shown in the graph of FIG. 2, there is a clear difference in the opening degree of the supercooling expansion valve 13.

Using this, the control device 28 detects the presence or absence of the liquid refrigerant in the receiver 11 during the cooling operation.
Specifically, during the cooling operation of the air conditioner 1, while controlling the opening degree of the supercooling expansion valve 13 as described above, the recovery-side automatic valve 21 c of the refrigerant recovery device 21 or the refrigerant supply device 22 is controlled. The supply-side automatic valve 22c is opened to take out the refrigerant from the refrigerant circuit 2 or add the refrigerant to the refrigerant circuit 2.
When the opening degree of the supercooling expansion valve 13 is reduced by removing the refrigerant or adding the refrigerant, it is determined that there is no liquid refrigerant in the receiver 11, and the refrigerant is taken out or the refrigerant If no clear change occurs in the opening degree of the supercooling expansion valve 13 even after the addition, it is determined that there is liquid refrigerant in the receiver 11.

  In addition, even when the amount of liquid refrigerant in the receiver 11 exceeds the appropriate range, the degree of opening of the supercooling expansion valve 13 changes, so this may be used to adjust the amount of refrigerant. Since the opening degree change due to the presence or absence of the liquid refrigerant in the receiver 11 is larger, the adjustment of the refrigerant amount based on the presence or absence of the liquid refrigerant in the receiver 11 can be performed with higher accuracy.

During the heating operation of the air conditioner 1, the refrigerant taken out from the bottom of the receiver 11 is fed into the heating expansion valve 5b as described above.
In the state where the liquid refrigerant is in the receiver 11, the liquid refrigerant is sufficiently supplied to the heating expansion valve 5b. Therefore, by setting the opening of the heating expansion valve 5b to a certain degree of opening, the outdoor heat The superheat degree operation | movement of the exchanger 4 is fully performed, and the refrigerant | coolant which passed the outdoor heat exchanger 4 can have a predetermined superheat degree. Here, the degree of superheat of the refrigerant that has passed through the indoor heat exchanger 6 is obtained based on the measurement value of the outdoor refrigerant temperature measurement device 24 and the measurement value of the low-pressure side refrigerant pressure measurement device 26.

On the other hand, in the state where there is no liquid refrigerant in the receiver 11, liquid refrigerant is not sufficiently supplied to the heating expansion valve 5 b, and flashing occurs and the refrigerant flow rate becomes insufficient. Therefore, the superheat operation by the outdoor heat exchanger 4 is performed. In order to make it sufficiently performed and to give the refrigerant having passed the outdoor heat exchanger 4 a predetermined degree of superheat, the opening degree of the heating expansion valve 5b must be increased.
That is, when the opening degree of the heating expansion valve 5b is controlled so that the refrigerant that has passed through the outdoor heat exchanger 4 has a predetermined degree of superheat, there are liquid refrigerant in the receiver 11 and no liquid refrigerant. Then, as shown in the graph of FIG. 3, a clear difference arises in the opening degree of the expansion valve 5b for heating.

Using this, the control device 28 detects the presence or absence of the liquid refrigerant in the receiver 11 during the heating operation.
Specifically, during the heating operation of the air conditioner 1, the supply of the recovery-side automatic valve 21c of the refrigerant recovery device 21 or the refrigerant supply device 22 is performed while controlling the opening degree of the heating expansion valve 5b as described above. The side automatic valve 22c is opened to take out the refrigerant from the refrigerant circuit 2 or add the refrigerant to the refrigerant circuit 2.
If the opening of the heating expansion valve 5b is reduced by removing the refrigerant or adding the refrigerant, it is determined that there is no liquid refrigerant in the receiver 11, and the refrigerant is taken out or added. If a clear change does not occur in the opening degree of the heating expansion valve 5b even after performing the above, it is determined that there is liquid refrigerant in the receiver 11.

  Note that when the amount of liquid refrigerant in the receiver 11 exceeds the appropriate range, the amount of supercooling is increased accordingly, and the opening of the heating expansion valve 5b changes. In this case, the amount of refrigerant may be adjusted by using the change of the heating expansion valve 5b. However, since the opening degree change due to the presence or absence of the liquid refrigerant in the receiver 11 is larger, the liquid refrigerant in the receiver 11 It is possible to adjust with higher accuracy by adjusting the refrigerant amount based on the presence or absence.

Here, the presence or absence of the liquid refrigerant in the receiver 11 during the heating operation of the air conditioner 1 is detected based on the opening degree of the heating expansion valve 5b as described above. It is also possible to detect based on the opening.
Hereinafter, the detection principle of the presence or absence of liquid refrigerant in the receiver 11 during the heating operation of the air-conditioning apparatus 1 based on the opening degree of the supercooling expansion valve 13 will be described.

During the heating operation of the air conditioner 1, when the liquid refrigerant is present in the receiver 11, the refrigerant is not required to be supercooled so much, so that the degree of opening of the supercooling expansion valve 13 is set to a certain degree of opening that is not so large. Thus, the refrigerant having passed through the outdoor heat exchanger 4 can have a predetermined degree of superheat.
On the other hand, in the state where there is no liquid refrigerant in the receiver 11, liquid refrigerant is not sufficiently supplied to the heating expansion valve 5 b, and flashing occurs and the refrigerant flow rate becomes insufficient. Therefore, the superheat operation by the outdoor heat exchanger 4 is performed. In order to give the refrigerant having passed through the outdoor heat exchanger 4 a predetermined degree of superheat sufficiently, the degree of supercooling is increased by increasing the degree of opening of the supercooling expansion valve 13 and the refrigerant sent to the receiver 11. It is necessary to have.

That is, when the opening degree of the supercooling expansion valve 13 is controlled so that the refrigerant that has passed through the outdoor heat exchanger 4 has a predetermined degree of superheat, there are liquid refrigerant in the receiver 11 and no liquid refrigerant. Then, a clear difference is generated in the opening degree of the supercooling expansion valve 13.
The control apparatus 28 detects the presence or absence of the liquid refrigerant in the receiver 11 using this.
Specifically, during the heating operation of the air conditioner 1, the refrigerant is taken out from the refrigerant circuit 2 or the refrigerant is added while controlling the opening degree of the supercooling expansion valve 13 as described above.
When the opening degree of the supercooling expansion valve 13 is reduced by removing the refrigerant or adding the refrigerant, it is determined that there is no liquid refrigerant in the receiver 11, and the refrigerant is taken out or the refrigerant If no clear change occurs in the opening degree of the supercooling expansion valve 13 even after the addition, it is determined that there is liquid refrigerant in the receiver 11.

Hereinafter, a specific operation of the air conditioner 1 will be described with reference to the flowcharts of FIGS. 4 and 5.
First, as shown in FIG. 4, when the air conditioner 1 is started, the control device 28 compares the measured value of the indoor atmosphere temperature measuring device with the set temperature set by the user and the like, and based on this result. An operation mode is determined (step S1).
When the room temperature exceeds the set temperature, the control device 28 causes the air conditioner 1 to perform a cooling operation (step S2). When the room temperature falls below the set temperature, the controller 28 heats the air conditioner 1. Operation is performed (step S3).

Since the refrigerant is vaporized by the indoor heat exchanger 6 by performing the cooling operation of the air conditioner 1, the refrigerant in the accumulator 16 is gradually reduced by continuing the cooling operation.
The control device 28 monitors the degree of superheat of the liquid in the liquid return channel 17 (step S4), and when the degree of superheat exceeds a predetermined temperature (assuming “α ° C”), the accumulator 16 It is determined that the liquid refrigerant in the tank has run out, and the refrigerant amount is adjusted.

The control device 28 controls the opening degree of the supercooling expansion valve 13 so that the degree of superheat of the refrigerant that has passed through the indoor heat exchanger 6 has a predetermined temperature (assuming “β ° C”). And whether to add refrigerant or to collect refrigerant is determined based on the opening degree (step S5).
Specifically, when the opening degree of the supercooling expansion valve 13 exceeds the appropriate range, the control device 28 determines that the amount of the refrigerant is insufficient and performs an additional operation of the refrigerant (step S6). ) When the opening degree of the supercooling expansion valve 13 is less than or equal to the appropriate range, it is determined that the amount of refrigerant is greater than or equal to the appropriate amount, and the refrigerant is collected (step S7).

The control device 28 collects the refrigerant in the refrigerant circuit 2 by the refrigerant collecting device 21 or determines whether the opening degree of the supercooling expansion valve 13 exceeds the proper range or the refrigerant supply device 22 in the refrigerant circuit 2. This is determined based on the amount of change in the degree of opening of the subcooling expansion valve 13 when the refrigerant is added.
Specifically, as described above, based on the relationship between the refrigerant amount and the opening degree of the supercooling expansion valve 13 shown in FIG. When the opening degree of the expansion valve 13 for supercooling clearly changes by adding, it is determined that the opening degree exceeds the appropriate range, and when the opening degree is substantially constant, the opening degree is within the appropriate range. It is determined that:

Hereinafter, the operation of adding the refrigerant during the cooling operation will be described.
The control device 28 opens the supply-side automatic valve 22 d of the refrigerant supply device 22 and adds refrigerant to the refrigerant circuit 2 little by little.
Here, since the refrigerant supply device 22 supplies the refrigerant to the low-pressure circuit side of the refrigerant circuit 2, the added refrigerant is also supplied to the accumulator 16. For this reason, the control device 28 again monitors the degree of superheat of the liquid in the liquid return passage 17 (step S8), and after determining that the liquid refrigerant in the accumulator 16 has run out, the control device 28 controls the expansion valve 13 for supercooling. It is confirmed whether the opening degree is stable (step S9). If the opening degree is stable, the adjustment operation of the refrigerant amount is finished (step S10), and if not, the process goes to step S6. Return and continue supplying refrigerant.

Hereinafter, the refrigerant recovery operation during the cooling operation will be described.
The control device 28 recovers the refrigerant by a certain amount by the refrigerant recovery device 21. In the present embodiment, the control device 28 defines a single extraction amount by repeating the operation of opening and closing the collection-side automatic valve 21c for a predetermined time T (instead of the collection-side automatic valve 21c). When a recovery-side electronic expansion valve is used, the amount of one extraction is defined by its opening and opening time).
The controller 28 monitors the opening degree of the supercooling expansion valve 13 while collecting the refrigerant in a certain amount in this way (step S11), and if the opening degree suddenly increases, the refrigerant amount falls below the appropriate range. The refrigerant recovery device 21 stops the recovery of the refrigerant, and the refrigerant supply device 22 is supplied with a predetermined amount of refrigerant equal to or less than the amount taken out once by the refrigerant recovery device 21 (step S12). The adjustment work is terminated (step S10).
In the present embodiment, the control device 28 opens the supply-side automatic valve 22c for a time equal to or shorter than the refrigerant supply time T per time by the refrigerant recovery device 21, for example, 1 / 2T, so that the amount of discharge is less than one time. Supply refrigerant.

Next, the operation | movement at the time of the heating operation of the air conditioning apparatus 1 is demonstrated (refer FIG. 5).
Since the refrigerant is vaporized by the indoor heat exchanger 6 by performing the heating operation of the air conditioner 1, the refrigerant in the accumulator 16 is gradually reduced by continuing the cooling operation.
The control device 28 monitors the degree of superheat of the liquid in the liquid return channel 17 (step S11), and when the degree of superheat exceeds a predetermined temperature α ° C., the liquid refrigerant in the accumulator 16 is exhausted. Judgment is made and the amount of refrigerant is adjusted.

The controller 28 controls the opening degree of the heating expansion valve 5b so that the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger 4 has a predetermined temperature (assuming “γ ° C”). Monitoring is performed, and it is determined based on the opening degree whether the refrigerant is added or the refrigerant is recovered (step S12).
Specifically, when the opening degree of the heating expansion valve 5b exceeds the appropriate range, the control device 28 determines that the amount of the refrigerant is insufficient and performs an additional operation of the refrigerant (step S13). When the opening of the heating expansion valve 5b is less than or equal to the appropriate range, it is determined that the amount of refrigerant is greater than or equal to the appropriate amount, and a refrigerant recovery operation is performed (step S14).

The control device 28 collects the refrigerant in the refrigerant circuit 2 by the refrigerant collecting device 21 or determines whether the opening degree of the heating expansion valve 5b exceeds the appropriate range or by the refrigerant supply device 22 in the refrigerant circuit 2. The determination is based on the amount of change in the opening of the heating expansion valve 5b when the refrigerant is added.
Specifically, as described above, the refrigerant in the refrigerant circuit 2 is recovered or added to the refrigerant circuit 2 based on the relationship between the refrigerant amount and the opening degree of the heating expansion valve 5b shown in FIG. When the opening degree of the heating expansion valve 5b clearly changes, it is determined that the opening degree exceeds the appropriate range. When the opening degree is substantially constant, the opening degree is less than the appropriate range. Judge that there is.

Hereinafter, an additional operation of the refrigerant during the heating operation will be described.
The control device 28 opens the supply-side automatic valve 22 d of the refrigerant supply device 22 and adds refrigerant to the refrigerant circuit 2 little by little.
Here, since the refrigerant supply device 22 supplies the refrigerant to the low-pressure circuit side of the refrigerant circuit 2, the added refrigerant is also supplied to the accumulator 16. For this reason, the control device 28 again monitors the degree of superheat of the liquid in the liquid return passage 17 (step S15), and after determining that the liquid refrigerant in the accumulator 16 has run out, the control device 28 controls the expansion valve 13 for supercooling. It is confirmed whether the opening degree is stable (step S16). If the opening degree is stable, the adjustment operation of the refrigerant amount is finished (step S17). If the opening degree is not stable, the process goes to step S13. Return and continue supplying refrigerant.

Hereinafter, the refrigerant recovery operation during the heating operation will be described.
The control device 28 recovers the refrigerant by a certain amount by the refrigerant recovery device 21. In the present embodiment, the control device 28 defines a single extraction amount by repeating the operation of opening and closing the collection-side automatic valve 21c for a certain time T.
The controller 28 monitors the opening degree of the supercooling expansion valve 13 while collecting the refrigerant in a certain amount in this way (step S18), and if the opening degree suddenly increases, the refrigerant amount falls below the appropriate range. The refrigerant recovery device 21 stops the recovery of the refrigerant, and the refrigerant supply device 22 is supplied with a predetermined amount of refrigerant equal to or less than a single extraction amount by the refrigerant recovery device 21 (step S19). The adjustment work is terminated (step S10).

As described above, according to the air conditioning apparatus 1 according to the present embodiment, the refrigerant amount of the refrigerant circuit 2 can be adjusted while accurately confirming the presence or absence of the liquid refrigerant in the receiver 11, so that the refrigerant It is possible to improve the operation efficiency by minimizing the amount of refrigerant in the circuit 2.
Further, in this air conditioner 1, since the liquid refrigerant in the receiver 11 is minimized with the excess refrigerant in the accumulator 16 being eliminated, the amount of refrigerant in the refrigerant circuit 2 is reduced while the accumulator 16 is provided. Can be minimized.

  Here, although the example which adjusts the refrigerant | coolant amount of the refrigerant circuit 2 based on the opening degree of the expansion valve 5b for heating at the time of heating operation of the air conditioning apparatus 1 was shown in this embodiment, it is not restricted to this. Even during the heating operation, the refrigerant amount of the refrigerant circuit 2 may be adjusted based on the opening degree of the supercooling expansion valve 13.

  In this case, as shown in the flowchart of FIG. 6, in order to suppress fluctuations in the refrigerant flow in the refrigerant circuit 2, the opening degree of the supercooling expansion valve 13 is basically fixed and the receiver 11 In the stage of determining the presence or absence of the liquid refrigerant (steps S12 and S18), prior to the determination of the presence or absence of the liquid refrigerant, the refrigerant that has passed through the outdoor heat exchanger 4 has an appropriate degree of superheat (assuming “δ” ° C.). ) To adjust the opening degree of the supercooling expansion valve 13 (steps S21 and S24), and the presence or absence of liquid refrigerant is determined based on the opening degree at this time. The opening degree of the valve 13 is fixed (steps S22 and S23).

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The air conditioner 31 according to this embodiment is characterized in that, in the air conditioner 1 shown in the first embodiment, the refrigerant recovery device 21 and the refrigerant supply device 22 are detachable from the refrigerant circuit 2. is there.
Hereinafter, the same or similar configurations as those of the air conditioner 1 shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the air conditioner 31, the recovery side connection pipe 21b of the refrigerant recovery device 21 is detachably connected to the refrigerant circuit 2 via a valve 21e. Then, by closing the valve 21e, the refrigerant circuit 2 and the recovery side connection pipe 21b can be shut off, and these can be attached and detached.

  Further, in the air conditioner 31, the supply side connection pipe 22b of the refrigerant supply device 22 is detachably connected to the refrigerant circuit 2 via the valve 22e. And by closing valve | bulb 22e, the refrigerant circuit 2 and the supply side connection piping 22b can be interrupted | blocked, and these can be attached or detached.

In the air conditioner 31 configured as described above, the refrigerant recovery device 21 and the refrigerant supply device 22 can be removed from the refrigerant circuit 2 except when necessary, so that the installation space of the air conditioner 31 can be reduced. it can.
Moreover, since at least any one of the refrigerant | coolant collection | recovery apparatus 21 and the refrigerant | coolant supply apparatus 22 can be shared between the some air conditioning apparatuses 31, apparatus cost can be reduced.

It is a figure which shows the structure of the air conditioning apparatus which concerns on 1st embodiment of this invention. It is a graph which shows the relationship between the refrigerant | coolant amount of a refrigerant circuit, and the opening degree of the expansion valve for supercooling. It is a graph which shows the relationship between the refrigerant | coolant amount of a refrigerant circuit, and the opening degree of the expansion valve for heating. It is a flowchart which shows operation | movement of the air conditioning apparatus which concerns on 1st embodiment of this invention. It is a flowchart which shows operation | movement of the air conditioning apparatus which concerns on 1st embodiment of this invention. It is a flowchart which shows the other example of the operation | movement at the time of the heating operation of the air conditioning apparatus which concerns on 1st embodiment of this invention. It is a figure which shows the structure of the air conditioning apparatus which concerns on 2nd embodiment of this invention.

Explanation of symbols

1,31 Air conditioner 2 Refrigerant circuit 3 Compressor 4 Outdoor heat exchanger (condenser, evaporator)
5a Expansion valve for cooling 5b Expansion valve for heating 6 Indoor heat exchanger (evaporator, condenser)
DESCRIPTION OF SYMBOLS 11 Receiver 12 Bypass flow path 13 Supercooling expansion valve 14 Supercooling heat exchanger 16 Accumulator 17 Liquid return flow path 21 Refrigerant recovery device 22 Refrigerant supply device 23 Indoor side refrigerant temperature measurement device 24 Outdoor refrigerant temperature measurement device 26 Low pressure side Refrigerant pressure measuring device 27 Return liquid temperature measuring device 28 Control device

Claims (14)

A compressor that compresses the refrigerant, a condenser that cools and liquefies the refrigerant delivered by the compressor, an expansion valve that expands the refrigerant that has passed through the condenser, and a refrigerant that has passed through the expansion valve is heated. The accumulator is connected to a refrigerant circuit having an evaporator to be vaporized, and an accumulator for temporarily storing refrigerant supplied from the evaporator to the compressor, by connecting a bottom portion of the accumulator and an upstream portion of the compressor. For an air conditioner configured to provide a liquid return flow path for supplying the liquid inside to the compressor,
A return liquid temperature measuring device for measuring the temperature of the liquid passing through the liquid return flow path;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
Detecting the degree of superheat of the liquid flowing through the liquid return channel based on the measurement value of the return liquid temperature measurement device and the measurement value of the low pressure side pressure measurement device;
A method for detecting liquid refrigerant in an accumulator of an air conditioner that determines that all liquid refrigerant has been discharged from within the accumulator when the degree of superheat has occurred in the liquid. A compressor that compresses the refrigerant; an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with outside air; and a receiver that temporarily stores the refrigerant that has passed through the outdoor heat exchanger; A refrigerant circuit having a cooling expansion valve that expands the refrigerant that has passed through the receiver, and an indoor heat exchanger that heats and vaporizes the refrigerant that has passed through the cooling expansion valve by heat exchange with the indoor atmosphere. A bypass flow path that extracts a part of the refrigerant in the receiver from the bottom of the receiver and supplies the refrigerant to the upstream side of the compressor, a supercooling expansion valve that expands the refrigerant supplied to the bypass flow path, and the receiver An air conditioner having a structure including a supercooling heat exchanger that supercools the refrigerant sent to the cooling expansion valve by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An indoor-side refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the indoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the cooling operation of the air conditioner, the degree of superheat of the refrigerant that has passed through the indoor heat exchanger is detected based on the measured value of the indoor refrigerant temperature measuring device and the measured value of the low pressure refrigerant pressure measuring device,
Adding refrigerant to the refrigerant circuit while controlling the opening of the expansion valve for supercooling so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that liquid refrigerant is present in the receiver at the time when the opening of the expansion valve for supercooling no longer changes. A compressor that compresses the refrigerant; an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere; and a receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger And a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and an outdoor heat exchanger that heats and vaporizes the refrigerant that has passed through the heating expansion valve by heat exchange with the outside air In the air conditioner consisting of
An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the heating operation of the air conditioner, detecting the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger based on the measurement value of the outdoor refrigerant temperature measurement device and the measurement value of the low-pressure refrigerant pressure measurement device,
Adding refrigerant to the refrigerant circuit while controlling the opening of the heating expansion valve so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that liquid refrigerant is present in the receiver when a change in the opening of the heating expansion valve no longer occurs. A compressor that compresses the refrigerant; an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere; and a receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger And a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and an outdoor heat exchanger that heats and vaporizes the refrigerant that has passed through the heating expansion valve by heat exchange with the outside air A bypass passage that supplies a part of the refrigerant that has passed through the indoor heat exchanger to the upstream side of the compressor, a supercooling expansion valve that expands the refrigerant supplied to the bypass passage, and the indoor An air conditioner having a configuration in which a supercooling heat exchanger that supercools the refrigerant sent from the heat exchanger to the receiver by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the heating operation of the air conditioner, detecting the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger based on the measurement value of the outdoor refrigerant temperature measurement device and the measurement value of the low-pressure refrigerant pressure measurement device,
Adding refrigerant to the refrigerant circuit while controlling the opening of the expansion valve for supercooling so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that liquid refrigerant is present in the receiver at the time when the opening of the expansion valve for supercooling no longer changes. A compressor that compresses the refrigerant; an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with outside air; and a receiver that temporarily stores the refrigerant that has passed through the outdoor heat exchanger; A refrigerant circuit having a cooling expansion valve that expands the refrigerant that has passed through the receiver, and an indoor heat exchanger that heats and vaporizes the refrigerant that has passed through the cooling expansion valve by heat exchange with the indoor atmosphere. A bypass flow path that extracts a part of the refrigerant in the receiver from the bottom of the receiver and supplies the refrigerant to the upstream side of the compressor, a supercooling expansion valve that expands the refrigerant supplied to the bypass flow path, and the receiver An air conditioner having a structure including a supercooling heat exchanger that supercools the refrigerant sent to the cooling expansion valve by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An indoor-side refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the indoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the cooling operation of the air conditioner, the degree of superheat of the refrigerant that has passed through the indoor heat exchanger is detected based on the measured value of the indoor refrigerant temperature measuring device and the measured value of the low pressure refrigerant pressure measuring device,
Taking out the refrigerant from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that liquid refrigerant in the receiver is exhausted when a change in the opening degree of the supercooling expansion valve occurs. A compressor that compresses the refrigerant; an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere; and a receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger And a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and an outdoor heat exchanger that heats and vaporizes the refrigerant that has passed through the heating expansion valve by heat exchange with the outside air In the air conditioner consisting of
An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the heating operation of the air conditioner, detecting the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger based on the measurement value of the outdoor refrigerant temperature measurement device and the measurement value of the low-pressure refrigerant pressure measurement device,
Taking out the refrigerant from the refrigerant circuit while controlling the opening of the heating expansion valve so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that the liquid refrigerant in the receiver is exhausted when a change in the opening of the heating expansion valve occurs. A compressor that compresses the refrigerant; an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere; and a receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger And a heating expansion valve that expands the refrigerant taken out from the bottom of the receiver, and an outdoor heat exchanger that heats and vaporizes the refrigerant that has passed through the heating expansion valve by heat exchange with the outside air A bypass passage that supplies a part of the refrigerant that has passed through the indoor heat exchanger to the upstream side of the compressor, a supercooling expansion valve that expands the refrigerant supplied to the bypass passage, and the indoor An air conditioner having a configuration in which a supercooling heat exchanger that supercools the refrigerant sent from the heat exchanger to the receiver by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger;
A low-pressure side refrigerant pressure measuring device for measuring the pressure of the refrigerant supplied to the compressor,
During the heating operation of the air conditioner, detecting the degree of superheat of the refrigerant that has passed through the outdoor heat exchanger based on the measurement value of the outdoor refrigerant temperature measurement device and the measurement value of the low-pressure refrigerant pressure measurement device,
Taking out the refrigerant from the refrigerant circuit while controlling the opening degree of the supercooling expansion valve so that the degree of superheat becomes a predetermined value,
A method for detecting liquid refrigerant in a receiver of an air conditioner that determines that liquid refrigerant in the receiver is exhausted when a change in the opening degree of the supercooling expansion valve occurs. The refrigerant is gradually added to the refrigerant circuit while determining the presence or absence of the liquid refrigerant in the receiver using the method for detecting liquid refrigerant in the receiver of the air conditioner according to any one of claims 2 to 4. ,
The refrigerant | coolant amount adjustment method of the air conditioning apparatus which stops the addition of the said refrigerant | coolant at the time of detecting the liquid refrigerant in the said receiver. The refrigerant in the refrigerant circuit is taken out step by step while determining the presence or absence of the liquid refrigerant in the receiver using the method for detecting liquid refrigerant in the receiver of the air conditioner according to any one of claims 5 to 7. Go,
When it is determined that the liquid refrigerant in the receiver is exhausted, the air conditioning apparatus completes the adjustment by stopping the extraction of the refrigerant and adding a predetermined amount of refrigerant that is less than a single extraction amount of the refrigerant to the refrigerant circuit. Refrigerant amount adjustment method. An air conditioner in which an accumulator and a receiver are provided in a refrigerant circuit, while detecting the amount of liquid refrigerant in the accumulator using the refrigerant amount detection method in the accumulator of the air conditioner according to claim 1, After driving until the refrigerant runs out,
A refrigerant quantity adjustment method for an air conditioner, wherein the refrigerant quantity in the refrigerant circuit is adjusted using the refrigerant quantity adjustment method for an air conditioner according to claim 8 or 9. A compressor that compresses the refrigerant; an outdoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with outside air; and a receiver that temporarily stores the refrigerant that has passed through the outdoor heat exchanger; A cooling expansion valve that expands the refrigerant that has passed through the receiver, an indoor heat exchanger that heats and vaporizes the refrigerant that has passed through the cooling expansion valve by heat exchange with the indoor atmosphere, and the bottom of the receiver A bypass flow path for taking out a part of the refrigerant in the receiver and supplying it to the upstream side of the compressor, a supercooling expansion valve for expanding the refrigerant supplied to the bypass flow path, and the cooling expansion from the receiver A refrigerant circuit having a supercooling heat exchanger that supercools the refrigerant sent to the valve by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An indoor-side refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the indoor heat exchanger;
A low-pressure side refrigerant pressure measuring device that measures the pressure of the refrigerant supplied to the compressor;
A refrigerant recovery device for recovering the refrigerant from the upstream side of the compressor of the refrigerant circuit;
A refrigerant supply device for supplying the refrigerant to the refrigerant circuit from the upstream side of the cooling expansion valve of the refrigerant circuit;
The operations of the cooling expansion valve, the supercooling expansion valve, the refrigerant recovery device, and the refrigerant supply device are controlled based on the refrigerant amount adjustment method of the air conditioner according to claim 8 or 9, thereby cooling the air. An air conditioner provided with a control device that adjusts the amount of refrigerant in the refrigerant circuit during operation. A compressor that compresses the refrigerant; an indoor heat exchanger that cools and liquefies the refrigerant delivered by the compressor by heat exchange with an indoor atmosphere; and a receiver that temporarily stores the refrigerant that has passed through the indoor heat exchanger A heating expansion valve that expands the refrigerant extracted from the bottom of the receiver, an outdoor heat exchanger that heats and vaporizes the refrigerant that has passed through the heating expansion valve by heat exchange with the outside air, and the indoor heat A bypass passage that supplies a part of the refrigerant that has passed through the exchanger to the upstream side of the compressor, an expansion valve for supercooling that expands the refrigerant supplied to the bypass passage, and the indoor heat exchanger In a refrigerant circuit having a supercooling heat exchanger that supercools the refrigerant sent to the receiver by heat exchange with the refrigerant expanded by the supercooling expansion valve,
An outdoor refrigerant temperature measuring device that measures the temperature of the refrigerant that has passed through the outdoor heat exchanger;
A low-pressure side refrigerant pressure measuring device that measures the pressure of the refrigerant supplied to the compressor;
A refrigerant recovery device for recovering the refrigerant from the upstream side of the compressor of the refrigerant circuit;
A refrigerant supply device for supplying the refrigerant to the refrigerant circuit from the upstream side of the heating expansion valve of the refrigerant circuit;
The operation of the expansion valve for heating, the expansion valve for supercooling, the refrigerant recovery device, and the refrigerant supply device is controlled and heated based on the refrigerant amount adjustment method of the air conditioner according to claim 8 or 9. An air conditioner provided with a control device that adjusts the amount of refrigerant in the refrigerant circuit during operation. An accumulator in which the refrigerant circuit temporarily stores the refrigerant supplied to the compressor;
A liquid return passage for connecting the bottom of the accumulator and the upstream part of the compressor to supply the liquid in the accumulator to the compressor;
A return liquid temperature measuring device for measuring the temperature of the liquid passing through the liquid return flow path,
The control device detects the degree of superheat of the liquid flowing through the liquid return channel based on the measurement value of the return liquid temperature measurement device and the measurement value of the low pressure side pressure measurement device, and the degree of superheat is generated in the liquid. The air conditioning apparatus according to claim 11 or 12, wherein the adjustment of the amount of refrigerant in the refrigerant circuit is started.   The air conditioning apparatus according to any one of claims 11 to 13, wherein at least one of the refrigerant recovery device and the refrigerant supply device is detachable from the refrigerant circuit.

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