JP2009210143A - Air conditioner and refrigerant amount determining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner preventing breakage of a liquid refrigerant communication pipe even under a condition that liquid refrigerant is expanded, and determining adequate refrigerant amount. <P>SOLUTION: This air conditioner 1 includes a refrigerant circuit 10, a cutoff mechanism 38, a refrigerant detecting mechanism 39, and expansion absorption mechanisms 24, 73. The cutoff mechanism cuts off the passing of the refrigerant between a heat source-side heat exchanger and the liquid refrigerant communication pipe in a cooling operation state. The refrigerant detecting mechanism detects the state quantity relating to the amount of refrigerant existing at an upstream side of the cutoff mechanism in the cooling operation state. The expansion absorption mechanism is connected to at least a liquid refrigerant pipe part between a use-side expansion mechanism including the liquid refrigerant communication pipe and the cutoff mechanism, and absorbs the expansion of the volume of the refrigerant inside of the liquid refrigerant pipe part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner and refrigerant amount determination that accurately determine whether or not the refrigerant amount is appropriate while preventing the pipe from being damaged in the air conditioner and refrigerant amount determination operation for determining the appropriateness of the refrigerant amount in the refrigerant circuit. Regarding driving.

  Conventionally, a heat source unit having a compressor and a heat source side heat exchanger and a utilization unit having a utilization side expansion valve and a utilization side heat exchanger are connected via a liquid refrigerant communication pipe and a gas refrigerant communication pipe. In order to determine the suitability of the refrigerant amount in the refrigerant circuit of the air conditioner constituted by the air conditioner, the air conditioner is operated under predetermined conditions.

In the technique of Patent Document 1, as an operating condition for determining the amount of refrigerant, a shut-off valve arranged upstream of the liquid refrigerant communication pipe in the refrigerant flow direction in the refrigerant circuit when performing cooling operation with the use side expansion valve The liquid refrigerant is contained in a portion of the refrigerant circuit between the utilization side expansion valve including the liquid refrigerant communication tube and the shutoff valve (hereinafter referred to as a liquid refrigerant closed portion), and the refrigerant in the refrigerant circuit is sealed by the shutoff valve. In this way, the refrigerant condensed in the heat source side heat exchanger functioning as a condenser is kept upstream of the shutoff valve in the refrigerant circuit and in the downstream portion of the compressor. A state in which almost no refrigerant is present in the downstream side of the use side expansion valve and in the upstream side of the compressor in the refrigerant circuit such as the use side heat exchanger or the gas refrigerant communication pipe by the operation of the compressor. West, In this state, the refrigerant detection mechanism detects a state quantity relating to the quantity of refrigerant concentrated in the refrigerant circuit upstream of the shut-off valve and downstream of the compressor, and the appropriate refrigerant quantity (See Patent Document 1).
JP 2006-023072 A

  However, the liquid refrigerant closed part exchanges heat with the surrounding air while detecting the state quantity related to the amount of refrigerant after the liquid refrigerant is enclosed in the liquid refrigerant closed part. The temperature of the liquid refrigerant may change. For this reason, when the temperature around the refrigerant communication pipe (outside air, ceiling, under floor temperature, etc.) is high, the liquid refrigerant inside the liquid refrigerant closed portion expands due to its temperature rise, and its volume increases. End up. In such a case, the liquid refrigerant communication pipe may not be able to absorb the expanded portion and may be damaged. It is also possible to provide a liquid seal prevention circuit that bypasses the pipes before and after the shut-off valve so that the liquid refrigerant communication pipe is not damaged even if the liquid refrigerant inside the liquid refrigerant closed portion expands. Since the liquid refrigerant returns to the heat source side heat exchanger through the circuit, there is a risk of causing a detection error in the method of determining the refrigerant amount as described above.

  An object of the present invention is to provide an air conditioner that can prevent the liquid refrigerant communication pipe from being damaged even under conditions such that the liquid refrigerant expands and can determine an appropriate amount of refrigerant. There is.

  An air conditioner according to a first aspect of the present invention includes a refrigerant circuit, a blocking mechanism, a refrigerant detection mechanism, and an expansion absorption mechanism. The refrigerant circuit includes a heat source unit, a utilization unit, a liquid refrigerant communication pipe and a gas refrigerant communication pipe. The heat source unit includes a compressor and a heat source side heat exchanger. The utilization unit has a utilization side expansion mechanism and a utilization side heat exchanger. The liquid refrigerant communication pipe and the gas refrigerant communication pipe connect the heat source unit and the utilization unit. The refrigerant circuit is a cooling operation in which the heat source side heat exchanger functions as a condenser for refrigerant compressed in the compressor, and the use side heat exchanger functions as an evaporator for refrigerant condensed in the heat source side heat exchanger. It is possible to perform at least the cooling operation in the state. The shut-off mechanism is arranged on the downstream side of the heat source side heat exchanger and the upstream side of the liquid refrigerant communication pipe in the flow direction of the refrigerant in the refrigerant circuit during the cooling operation, and can block the passage of the refrigerant. The refrigerant detection mechanism is arranged on the upstream side of the shut-off valve in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and detects the amount of the refrigerant existing on the upstream side of the shut-off valve. The expansion absorption mechanism is at least connected to the liquid refrigerant pipe portion between the utilization side expansion mechanism including the liquid refrigerant communication pipe and the blocking mechanism, and can absorb the expansion of the volume of the refrigerant inside the liquid refrigerant pipe portion.

  In the air conditioner of the present invention, while the refrigerant circuit is operating in the cooling operation state, the shut-off mechanism provided on the downstream side of the heat source side heat exchanger is closed to shut off the flow of the refrigerant. For example, the liquid refrigerant condensed in the heat source side heat exchanger functioning as a condenser is mainly accumulated in the heat source side heat exchanger upstream of the shut-off mechanism because the circulation of the refrigerant is interrupted. To go. On the other hand, when the compressor is driven in the cooling operation state, a portion of the refrigerant circuit downstream of the shut-off mechanism and upstream of the compressor, for example, a use side heat exchanger or a gas refrigerant communication pipe is decompressed. Thus, almost no refrigerant is present. For this reason, the refrigerant in the refrigerant circuit is intensively collected on the upstream side of the shut-off mechanism, and the refrigerant detection mechanism performs detection related to the intensively collected refrigerant amount. And in this air conditioner, the amount of expansion of the volume of the liquid refrigerant confined in the liquid refrigerant piping part by closing the shut-off mechanism as described above (for example, due to changes in ambient temperature conditions, etc.), An expansion absorbing mechanism is provided so as to absorb water.

  Therefore, in the air conditioner of the present invention, when control is performed such that the liquid refrigerant pipe portion is closed, after the liquid refrigerant pipe portion is closed, for example, the inside of the liquid refrigerant pipe portion due to a change in ambient temperature conditions The expansion of the volume of the liquid refrigerant can be absorbed. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. Similarly, when the volume of the liquid refrigerant in the liquid refrigerant pipe portion is expanded, for example, a safety device such as a high pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided. Even in such a case, since the refrigerant can be contained without escaping from the liquid refrigerant pipe portion, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  An air conditioner according to a second aspect of the present invention is the air conditioner according to the first aspect of the present invention, further comprising operation control means and refrigerant amount determination means. The operation control means performs liquid temperature constant control for controlling the refrigerant temperature in the liquid refrigerant pipe portion to be a constant value in the cooling operation state, and performs liquid pipe closing control for closing the shut-off mechanism and the use side expansion mechanism. Then, liquid refrigerant storage control is performed to store the liquid refrigerant in the upstream portion of the shut-off mechanism. The refrigerant amount determination means determines whether or not the refrigerant amount in the refrigerant circuit is appropriate based on the state quantity related to the refrigerant amount detected by the refrigerant detection mechanism in the liquid refrigerant storage control.

  In the air conditioner of the present invention, the liquid that controls the temperature of the liquid refrigerant flowing through the liquid refrigerant pipe portion between the utilization side expansion mechanism including the liquid refrigerant communication pipe and the cutoff mechanism in the refrigerant circuit to be a constant value. Constant temperature control is performed by the operation control means. By performing this liquid temperature constant control, the inside of the liquid refrigerant pipe portion is stably sealed by the liquid refrigerant at a constant temperature. As a result, the temperature of the refrigerant sent from the heat source side heat exchanger to the utilization side expansion mechanism through the liquid refrigerant communication pipe is adjusted to be constant, and the amount of refrigerant fixed inside the liquid refrigerant pipe portion is maintained. By closing the side expansion mechanism and the shut-off mechanism, the amount of liquid refrigerant fixed to the liquid refrigerant pipe portion of the refrigerant circuit is contained (liquid pipe closing control). Then, with the liquid refrigerant contained in the liquid refrigerant piping portion, the operation control means performs liquid refrigerant storage control in which the liquid refrigerant is stored in the upstream portion of the shut-off mechanism in the cooling operation state, and is stored on the upstream side of the shut-off mechanism. The refrigerant detection mechanism detects a state quantity related to the refrigerant quantity of the liquid refrigerant, and the refrigerant quantity determination means determines whether the refrigerant quantity in the refrigerant circuit is appropriate based on the state quantity. Furthermore, in this air conditioner, the volume of the liquid refrigerant confined in the liquid refrigerant piping part by closing the shut-off mechanism as described above (for example, due to changes in ambient temperature conditions, etc.), An expansion absorbing mechanism is provided so as to absorb water.

  Therefore, in the air conditioner of the present invention, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in ambient temperature conditions, the expansion absorption mechanism Thus, the expansion can be absorbed. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. Similarly, when the volume of the liquid refrigerant in the liquid refrigerant pipe portion is expanded, for example, a safety device such as a high pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided. Even in such a case, since the refrigerant can be contained without escaping from the liquid refrigerant pipe portion, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  An air conditioner according to a third aspect of the present invention is the air conditioner according to the second aspect of the present invention, further comprising a first opening / closing mechanism and a second opening / closing mechanism. The first opening / closing mechanism is provided in a first flow path that connects one end of the expansion absorption mechanism and the liquid refrigerant piping portion, and can connect or disconnect the liquid refrigerant piping portion and the expansion absorption mechanism. It is. The second opening / closing mechanism is provided in a second flow path that connects the other end of the expansion absorption mechanism and a gas refrigerant pipe portion between the gas refrigerant communication pipe and the compressor, and includes the gas refrigerant pipe portion and the expansion absorption mechanism. It is possible to make it a communication state or a blocking state. Then, the operation control means closes the first opening / closing mechanism and opens the second opening / closing mechanism during the constant liquid temperature control, and opens the first opening / closing mechanism and closes the second opening / closing mechanism after the liquid pipe closing control. To.

  In the air conditioner of the present invention, during the constant liquid temperature control, the first opening / closing mechanism provided in the first flow path that connects one end of the expansion absorption mechanism and the liquid refrigerant piping portion is closed, and the expansion absorption mechanism The second opening / closing mechanism provided in the second flow path connecting the other end and the gas refrigerant pipe portion between the gas refrigerant communication pipe and the compressor is opened. Then, after the liquid temperature constant control is completed and the liquid pipe closing control is performed, the first opening / closing mechanism is opened and the second opening / closing mechanism is closed. That is, the liquid refrigerant piping part is controlled so that the inside of the liquid refrigerant pipe part is stably sealed by the liquid refrigerant at a constant temperature, and the amount of refrigerant fixed inside the liquid refrigerant pipe part is maintained. Then, after the amount of refrigerant fixed to the liquid refrigerant pipe part is contained by the liquid pipe closing control, the first opening / closing mechanism is opened to connect the liquid refrigerant pipe part and the expansion absorption mechanism, and the second opening / closing mechanism is closed. By doing so, the amount of the refrigerant confined by the liquid pipe closing control is confined in a portion where the inside of the liquid refrigerant pipe portion and the inside of the expansion absorption mechanism are combined.

  Therefore, the liquid refrigerant pipe portion and the expansion absorption mechanism connected to the liquid refrigerant pipe portion are made to communicate with each other after the amount of liquid refrigerant fixed in the liquid refrigerant pipe portion is contained and the refrigerant amount is fixed. Thus, the volume of the liquid refrigerant confined in the liquid refrigerant piping portion can be released by the volume of the expansion absorption mechanism. For this reason, even if the liquid refrigerant confined in the liquid refrigerant pipe portion expands due to a change in the ambient temperature, the expansion can be absorbed by the volume of the expansion absorption mechanism. Thereby, it can prevent that a liquid refrigerant piping part is damaged by liquid refrigerant expanding.

  An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the third aspect of the present invention, further comprising a supercooler. The subcooler can cool the refrigerant condensed in the heat source side heat exchanger during operation in the cooling operation state. The first opening / closing mechanism functions as an expansion mechanism that depressurizes the refrigerant flowing to the subcooler. The first flow path includes a flow path on the cooling source side of the subcooler that cools the refrigerant sent from the heat source side heat exchanger to the utilization side expansion mechanism with the refrigerant reduced in pressure by the first opening / closing mechanism.

  The air conditioner of the present invention further includes a supercooler, and the first opening / closing mechanism functions as an expansion mechanism that decompresses the refrigerant flowing to the supercooler. The first flow path also serves as a bypass circuit that serves as a cooling source for the subcooler, and the first opening / closing mechanism functions as an expansion mechanism that reduces the pressure when the refrigerant from the first flow path is introduced into the subcooler. ing.

  Therefore, in the air conditioner in which the supercooler is installed as in the present invention, the bypass circuit serving as a cooling source for the supercooler is connected to the liquid refrigerant pipe portion and the expansion absorption mechanism by the first circuit. It can be used as a flow path. For this reason, a component can be reduced and a production cost can be reduced.

  An air conditioner according to a fifth aspect of the present invention is the air conditioner according to the third or fourth aspect of the present invention, wherein the expansion absorption mechanism is provided on the suction side of the compressor and separates the refrigerant into liquid refrigerant and gas refrigerant. Thus, it functions as an accumulator capable of supplying only the gas refrigerant to the compressor.

  In the air conditioner of the present invention, the accumulator functions as an expansion absorption mechanism. Therefore, it is not necessary to provide a new expansion absorbing mechanism independently, and the production cost can be reduced.

  An air conditioner according to a sixth aspect of the present invention includes a refrigerant circuit, a first shut-off mechanism, a refrigerant detection mechanism, an operation control unit, a refrigerant amount determination unit, and a liquid refrigerant determination unit. The refrigerant circuit includes a heat source unit, a utilization unit, a liquid refrigerant communication pipe and a gas refrigerant communication pipe. The heat source unit includes a compressor and a heat source side heat exchanger. The utilization unit has a utilization side expansion mechanism and a utilization side heat exchanger. The liquid refrigerant communication pipe and the gas refrigerant communication pipe connect the heat source unit and the utilization unit. The refrigerant circuit is a cooling operation in which the heat source side heat exchanger functions as a condenser for refrigerant compressed in the compressor, and the use side heat exchanger functions as an evaporator for refrigerant condensed in the heat source side heat exchanger. Can be performed at least. The first shut-off mechanism is disposed downstream of the heat source side heat exchanger and upstream of the liquid refrigerant communication pipe in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and can block passage of the refrigerant. . The refrigerant detection mechanism is arranged on the upstream side of the shut-off valve in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and detects the amount of the refrigerant existing on the upstream side of the shut-off valve. The second blocking mechanism is provided between the use-side heat exchanger and the compression mechanism, and can block the passage of the refrigerant. The operation control means performs a liquid temperature constant control for controlling the refrigerant temperature of the liquid refrigerant pipe part to be a constant value in the cooling operation, performs a liquid pipe closing control for closing the shut-off mechanism and the use side expansion mechanism, Liquid refrigerant storage control is performed to store liquid refrigerant in the upstream portion of the shut-off mechanism. The refrigerant amount determination means determines whether or not the refrigerant amount in the refrigerant circuit is appropriate based on the state quantity related to the refrigerant amount detected by the refrigerant detection mechanism in the liquid refrigerant storage control. The liquid refrigerant determining means determines whether or not liquid refrigerant exists in the use side heat exchanger. The operation control means is performing the liquid refrigerant storage control, and after the liquid refrigerant determination means determines that there is no liquid refrigerant in the use side heat exchanger, the operation control means closes the second shut-off mechanism and sets the use side expansion mechanism to Open.

  In the air conditioner of the present invention, after the liquid refrigerant determining means determines that there is no liquid refrigerant in the use side heat exchanger, the second shut-off mechanism is closed and the use side expansion mechanism is opened. Therefore, the use side heat exchanger can be used as an expansion absorption mechanism capable of releasing the volume of the liquid refrigerant confined in the liquid refrigerant pipe portion. For this reason, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in ambient temperature conditions, the use side heat exchanger reduces the expansion amount. Can be absorbed. Thereby, it is possible to prevent the liquid refrigerant piping portion from being damaged due to the expansion of the liquid refrigerant sealed inside the liquid refrigerant piping portion. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  According to a seventh aspect of the present invention, there is provided a refrigerant amount determination method comprising: a heat source unit having a compressor and a heat source side heat exchanger; a utilization unit having a utilization side expansion mechanism and a utilization side heat exchanger; a heat source unit and a utilization unit. Including a liquid refrigerant communication pipe and a gas refrigerant communication pipe to be connected, the heat source side heat exchanger as a refrigerant condenser to be compressed in the compressor, and the use side heat exchanger to be condensed in the heat source side heat exchanger In an air conditioner having a refrigerant circuit capable of performing at least a cooling operation to function as a refrigerant evaporator, a refrigerant amount determination method for determining the suitability of the refrigerant amount in the refrigerant circuit, wherein the cooling operation is performed A shut-off mechanism disposed on the downstream side of the heat source side heat exchanger and the upstream side of the liquid refrigerant communication pipe in the flow direction of the refrigerant in the refrigerant circuit, and a use-side expansion mechanism Liquid temperature constant control is performed to control the refrigerant temperature of the liquid refrigerant piping part to be a constant value, and at least connected to the liquid refrigerant piping part between the use-side expansion mechanism including the liquid refrigerant communication pipe and the blocking mechanism, Provided in the first flow path connecting one end of the expansion absorption mechanism capable of absorbing the expansion of the volume of the refrigerant inside the liquid refrigerant piping portion and the liquid refrigerant piping portion, and the refrigerant flows out from the liquid refrigerant piping portion to the expansion absorption mechanism The first opening / closing mechanism that can be turned on is closed during constant liquid temperature control, and the other end of the expansion absorption mechanism is connected to the gas refrigerant piping portion between the gas refrigerant communication pipe and the compressor. The second opening / closing mechanism that is provided in the second flow path that allows the refrigerant to flow in and out from the gas refrigerant pipe portion to the expansion absorption mechanism is opened during the constant liquid temperature control, and the blocking mechanism and the use side expansion are opened. Liquid pipe closing control to close the mechanism and liquid After the closing control, the first opening / closing mechanism is opened, the second opening / closing mechanism is closed, the refrigerant amount determination operation for storing the liquid refrigerant in the upstream portion of the shut-off mechanism is performed, and the cooling circuit when performing the cooling operation A state quantity related to the amount of refrigerant existing upstream of the shut-off mechanism is obtained by a refrigerant detection mechanism that is arranged upstream of the shut-off mechanism in the refrigerant flow direction and detects a state quantity related to the amount of refrigerant existing upstream of the shut-off mechanism. The refrigerant quantity is detected and the suitability of the refrigerant quantity in the refrigerant circuit is judged based on the state quantity relating to the refrigerant quantity detected by the refrigerant detection mechanism in the refrigerant quantity judgment operation.

  In the refrigerant amount determination method of the present invention, control is performed so that the temperature of the liquid refrigerant flowing through the liquid refrigerant pipe portion between the use-side expansion mechanism including the liquid refrigerant communication pipe and the cutoff mechanism in the refrigerant circuit becomes a constant value. The liquid temperature constant control is performed by the operation control means. By performing this liquid temperature constant control, the inside of the liquid refrigerant pipe portion is stably sealed by the liquid refrigerant at a constant temperature. As a result, the temperature of the refrigerant sent from the heat source side heat exchanger to the utilization side expansion mechanism through the liquid refrigerant communication pipe is adjusted to be constant, and the amount of refrigerant fixed inside the liquid refrigerant pipe portion is maintained. By closing the side expansion mechanism and the shut-off mechanism, the amount of liquid refrigerant fixed to the liquid refrigerant pipe portion of the refrigerant circuit is contained (liquid pipe closing control). Then, with the liquid refrigerant contained in the liquid refrigerant piping portion, the operation control means performs liquid refrigerant storage control in which the liquid refrigerant is stored in the upstream portion of the shut-off mechanism in the cooling operation state, and is stored on the upstream side of the shut-off mechanism. The refrigerant detection mechanism detects a state quantity related to the refrigerant quantity of the liquid refrigerant, and the refrigerant quantity determination means determines whether the refrigerant quantity in the refrigerant circuit is appropriate based on the state quantity. Furthermore, in this air conditioner, the volume of the liquid refrigerant confined in the liquid refrigerant piping part by closing the shut-off mechanism as described above (for example, due to changes in ambient temperature conditions, etc.), An expansion absorbing mechanism is provided so as to absorb water.

  Therefore, in the refrigerant quantity determination method of the present invention, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in the ambient temperature condition, the expansion absorption The expansion can be absorbed by the mechanism. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  In the air conditioner according to the first aspect of the present invention, when the control is performed such that the liquid refrigerant pipe portion is closed, the liquid refrigerant volume inside the liquid refrigerant pipe portion is expanded after the liquid refrigerant pipe portion is closed. (Eg, due to changes in ambient temperature conditions) can be absorbed. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  In the air conditioner according to the second aspect of the present invention, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in ambient temperature conditions, the expansion absorption mechanism Thus, the expansion can be absorbed. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  In the air conditioner according to the third aspect of the invention, the liquid refrigerant of the amount of refrigerant fixed to the liquid refrigerant pipe part is contained, and the refrigerant quantity is fixed and then communicated with the expansion absorption mechanism connected to the liquid refrigerant pipe part. By doing so, the volume of the liquid refrigerant confined in the liquid refrigerant pipe portion can be released by the volume of the expansion absorption mechanism. For this reason, even if the liquid refrigerant confined in the liquid refrigerant pipe portion expands due to a change in the ambient temperature, the expansion can be absorbed by the volume of the expansion absorption mechanism. Thereby, it can prevent that a liquid refrigerant piping part is damaged by liquid refrigerant expanding.

  In the air conditioner according to the fourth aspect of the present invention, in an air conditioner in which a supercooler is installed, a bypass circuit serving as a cooling source for the supercooler is used for the first flow path connected to the expansion absorbing mechanism. be able to. For this reason, a component can be reduced and a production cost can be reduced.

  In the air conditioner according to the fifth aspect of the present invention, it is not necessary to provide a new expansion absorption mechanism independently, and the production cost can be reduced.

  In the air conditioner according to the sixth aspect of the present invention, the use-side heat exchanger can be used as an expansion absorption mechanism capable of releasing the volume of the liquid refrigerant confined in the liquid refrigerant pipe portion. For this reason, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in ambient temperature conditions, the use side heat exchanger reduces the expansion amount. Can be absorbed. Thereby, it can prevent that a liquid refrigerant piping part is damaged, when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  In the refrigerant quantity determination method according to the seventh aspect of the present invention, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion changes due to a change in ambient temperature conditions, the expansion absorption The expansion can be absorbed by the mechanism. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. In the same case, for example, even when a safety device such as a high-pressure control valve for releasing the high pressure in the liquid refrigerant pipe portion is provided, the refrigerant can be contained without leaking from the liquid refrigerant pipe portion. Therefore, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

  Hereinafter, an embodiment of an air-conditioning apparatus and a refrigerant amount determination method according to the present invention will be described based on the drawings.

(First embodiment)
(1) Configuration of Air Conditioner FIG. 1 is a schematic configuration diagram of an air conditioner 1 according to the first embodiment of the present invention. The air conditioner 1 is an apparatus used for air conditioning in a room such as a building by performing a vapor compression refrigeration cycle operation. The air conditioner 1 mainly includes an outdoor unit 2 as one heat source unit, indoor units 4 and 5 as a plurality of (two in the present embodiment) usage units connected in parallel thereto, and an outdoor unit. A liquid refrigerant communication pipe 6 and a gas refrigerant communication pipe 7 are provided as refrigerant communication pipes connecting the unit 2 and the indoor units 4 and 5. That is, the vapor compression refrigerant circuit 10 of the air conditioner 1 of the present embodiment includes the outdoor unit 2, the indoor units 4, 5, the liquid refrigerant communication pipe 6, and the gas refrigerant communication pipe 7. It is configured.

<Indoor unit>
The indoor units 4 and 5 are installed by embedding or hanging in a ceiling of a room such as a building or by hanging on a wall surface of the room. The indoor units 4 and 5 are connected to the outdoor unit 2 via a liquid refrigerant communication pipe 6 and a gas refrigerant communication pipe 7 and constitute a part of the refrigerant circuit 10.

  Next, the configuration of the indoor units 4 and 5 will be described. In addition, since the indoor unit 4 and the indoor unit 5 have the same configuration, only the configuration of the indoor unit 4 will be described here, and the configuration of the indoor unit 5 is the 40th number indicating each part of the indoor unit 4. The reference numerals in the 50s are attached instead of the reference numerals, and description of each part is omitted.

  The indoor unit 4 mainly has an indoor refrigerant circuit 10a (in the indoor unit 5, the indoor refrigerant circuit 10b) that constitutes a part of the refrigerant circuit 10. This indoor refrigerant circuit 10a mainly has an indoor expansion valve 41 as a use side expansion mechanism and an indoor heat exchanger 42 as a use side heat exchanger.

  In the present embodiment, the indoor expansion valve 41 is an electric expansion valve connected to the liquid side of the indoor heat exchanger 42 in order to adjust the flow rate of the refrigerant flowing in the indoor refrigerant circuit 10a. It is also possible to block the passage.

  In the present embodiment, the indoor heat exchanger 42 is a cross-fin type fin-and-tube heat exchanger composed of heat transfer tubes and a large number of fins, and functions as a refrigerant evaporator during cooling operation. It is a heat exchanger that cools indoor air and functions as a refrigerant condenser during heating operation to heat indoor air. In the present embodiment, the indoor heat exchanger 42 is a cross-fin type fin-and-tube heat exchanger, but is not limited thereto, and may be another type of heat exchanger.

  In the present embodiment, the indoor unit 4 sucks indoor air into the unit, exchanges heat with the refrigerant in the indoor heat exchanger 42, and then supplies the indoor fan 43 as a blower fan to be supplied indoors as supply air. have. The indoor fan 43 is a fan capable of changing the air volume supplied to the indoor heat exchanger 42. In this embodiment, the indoor fan 43 is a centrifugal fan or a multiblade fan driven by a motor 43m formed of a DC fan motor or the like. Etc.

  The indoor unit 4 is provided with various sensors. On the liquid side of the indoor heat exchanger 42, a liquid side temperature sensor 44 that detects the temperature of the refrigerant (that is, the refrigerant temperature corresponding to the condensation temperature during heating operation or the evaporation temperature during cooling operation) is provided. A gas side temperature sensor 45 that detects the temperature of the refrigerant is provided on the gas side of the indoor heat exchanger 42. An indoor temperature sensor 46 that detects the temperature of indoor air flowing into the unit (that is, the indoor temperature) is provided on the indoor air inlet side of the indoor unit 4. In the present embodiment, the liquid side temperature sensor 44, the gas side temperature sensor 45, and the room temperature sensor 46 are thermistors. The indoor unit 4 also has an indoor control unit 47 that controls the operation of each part constituting the indoor unit 4. And the indoor side control part 47 has the microcomputer, memory, etc. which were provided in order to control the indoor unit 4, and is with the remote control (not shown) for operating the indoor unit 4 separately. Control signals and the like can be exchanged between them, and control signals and the like can be exchanged with the outdoor unit 2 via the transmission line 8a.

<Outdoor unit>
The outdoor unit 2 is installed outside a building or the like, and is connected to the indoor units 4 and 5 via the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7, and the refrigerant circuit 10 is connected to the indoor units 4 and 5 together. It is composed.

  Next, the configuration of the outdoor unit 2 will be described. The outdoor unit 2 mainly has an outdoor refrigerant circuit 10 c that constitutes a part of the refrigerant circuit 10. The outdoor refrigerant circuit 10c mainly includes a compressor 21, a four-way switching valve 22, an outdoor heat exchanger 23 as a heat source side heat exchanger, an outdoor expansion valve 38 as an expansion mechanism, an accumulator 24, It has a supercooler 25 as a temperature adjusting mechanism, an expansion tank 73 as an expansion absorbing mechanism that absorbs expansion of the volume of the refrigerant, a liquid side closing valve 26, and a gas side closing valve 27.

  The compressor 21 is a compressor whose operating capacity can be varied. In the present embodiment, the compressor 21 is a positive displacement compressor driven by a motor 21m whose rotation speed is controlled by an inverter. In the present embodiment, only one compressor 21 is provided, but the present invention is not limited to this, and two or more compressors may be connected in parallel depending on the number of indoor units connected. .

  The four-way switching valve 22 is a valve for switching the flow direction of the refrigerant. During the cooling operation, the outdoor heat exchanger 23 is used as a refrigerant condenser compressed by the compressor 21 and the indoor heat exchanger 42. , 52 is connected to the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 in order to function as an evaporator of refrigerant condensed in the outdoor heat exchanger 23 (specifically Specifically, the accumulator 24) and the gas refrigerant communication pipe 7 side are connected (cooling operation state: refer to the solid line of the four-way switching valve 22 in FIG. 1), and the indoor heat exchangers 42 and 52 are compressed during the heating operation. In order to allow the outdoor heat exchanger 23 to function as a refrigerant evaporator to be condensed in the indoor heat exchangers 42 and 52, as a refrigerant condenser compressed by the machine 21, the discharge side of the compressor 21 and the gas refrigerant Contact With connecting the 7-side it is possible to connect the gas side of the suction side and the outdoor heat exchanger 23 of the compressor 21 (the heating operation state: see the broken lines of the four-way switching valve 22 in FIG. 1).

  In the present embodiment, the outdoor heat exchanger 23 is a cross-fin type fin-and-tube heat exchanger, and as shown in FIG. 2, heat mainly composed of a heat transfer tube and a large number of fins. It has an exchanger body 23a, a header 23b connected to the gas side of the heat exchanger body 23a, and a flow divider 23c connected to the liquid side of the heat exchanger body 23a. Here, FIG. 2 is a schematic view of the outdoor heat exchanger 23. The outdoor heat exchanger 23 is a heat exchanger that functions as a refrigerant condenser during the cooling operation and functions as a refrigerant evaporator during the heating operation. The outdoor heat exchanger 23 has a gas side connected to the four-way switching valve 22 and a liquid side connected to the outdoor expansion valve 38. Further, as shown in FIG. 2, the outdoor heat exchanger 23 is disposed on the upstream side of the liquid side shut-off valve 26 in the refrigerant flow direction in the refrigerant circuit 10 when performing the cooling operation. A liquid level detection sensor 39 is provided as a refrigerant detection mechanism that detects a state quantity relating to the refrigerant quantity existing on the upstream side of the expansion valve 38. The liquid level detection sensor 39 is a sensor for detecting the amount of liquid refrigerant accumulated in the outdoor heat exchanger 23 as a state quantity related to the refrigerant amount existing on the upstream side of the outdoor expansion valve 38, and the outdoor heat exchanger. It is comprised by the tubular detection member arrange | positioned along the height direction of 23 (more specifically, header 23b). Here, in the case of the cooling operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 21 is cooled and condensed by the air supplied by the outdoor fan 28 in the outdoor heat exchanger 23, and the high-pressure liquid Becomes a refrigerant. That is, the liquid level detection sensor 39 detects a boundary between a region where the refrigerant exists in a gas state and a region where the refrigerant exists in the liquid state as a liquid level. The liquid level detection sensor 39 is not limited to such a tubular detection member. For example, the liquid level detection sensor 39 is arranged at a plurality of locations along the height direction of the outdoor heat exchanger 23 (more specifically, the header 23b). A boundary between a portion of the gas refrigerant higher than the ambient temperature of the outdoor heat exchanger 23 and a portion of the liquid refrigerant having a temperature similar to the ambient temperature of the outdoor heat exchanger 23. May be detected as the liquid level. In the present embodiment, the outdoor heat exchanger 23 is a cross-fin type fin-and-tube heat exchanger, but is not limited thereto, and may be another type of heat exchanger. In this embodiment, the header 23b is provided at one end of the heat exchanger main body 23a, and the flow divider 23c is provided at the other end of the heat exchanger main body 23a. The heat exchanger 23c may be provided at the same end of the heat exchanger body 23a.

  In the present embodiment, the outdoor expansion valve 38 performs outdoor heat exchange in the refrigerant flow direction in the refrigerant circuit 10 during the cooling operation in order to adjust the pressure, flow rate, and the like of the refrigerant flowing in the outdoor refrigerant circuit 10c. This is an electric expansion valve disposed downstream of the cooler 23 and upstream of the subcooler 25 (in this embodiment, connected to the liquid side of the outdoor heat exchanger 23), and allows passage of refrigerant. It is also possible to shut off. A portion between the indoor expansion valves 41 and 51 including the liquid refrigerant communication pipe 7 in the refrigerant circuit 10 and the outdoor expansion valve 38 (hereinafter referred to as liquid refrigerant pipe) is connected to a pipe bypassing the pipe before and after the outdoor expansion valve 38. In order to prevent the liquid refrigerant pipe portion from being damaged, a high pressure control valve 77 is provided that can flow out to the outdoor heat exchanger 23 when the pressure of the liquid refrigerant inside the liquid refrigerant pipe portion exceeds a predetermined pressure. Thereby, it becomes possible to prevent damage to the liquid refrigerant piping part due to temperature rise or the like.

  In the present embodiment, the outdoor unit 2 has an outdoor fan 28 as a blower fan for sucking outdoor air into the unit, exchanging heat with the refrigerant in the outdoor heat exchanger 23, and then discharging the air outside. ing. The outdoor fan 28 is a fan capable of changing the air volume supplied to the outdoor heat exchanger 23. In the present embodiment, the outdoor fan 28 is a propeller fan or the like driven by a motor 28m composed of a DC fan motor or the like. .

  The accumulator 24 is connected between the four-way selector valve 22 and the compressor 21 and can accumulate surplus refrigerant generated in the refrigerant circuit 10 in accordance with fluctuations in the operating load of the indoor units 4 and 5. It is a container.

  In the present embodiment, the subcooler 25 includes a double pipe heat exchanger, a refrigerant pipe through which the refrigerant condensed in the heat source side heat exchanger flows, and a first bypass refrigerant pipe 61 and a first first bypass refrigerant described later. A pipe heat exchanger configured by bringing the pipe 61 into contact with the outdoor heat exchanger 23 in order to cool the refrigerant sent to the indoor expansion valves 41 and 51 after being condensed in the outdoor heat exchanger 23. And the liquid refrigerant communication pipe 6. More specifically, the supercooler 25 is connected between the outdoor expansion valve 38 and the liquid side closing valve 26.

  In this embodiment, the 1st bypass refrigerant | coolant piping 61 as a cooling source of the subcooler 25 is provided. In the following description, a portion excluding the first bypass refrigerant pipe 61 and a second bypass refrigerant pipe 71 described later from the refrigerant circuit 10 will be referred to as a main refrigerant circuit for convenience. The first bypass refrigerant pipe 61 branches a part of the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 from the main refrigerant circuit, depressurizes the branched refrigerant, and then passes to the subcooler 25. After being introduced and heat exchanged with the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 through the liquid refrigerant communication pipe 6, it is connected to the main refrigerant circuit so as to return to the suction side of the compressor 21. Yes. Specifically, the first bypass refrigerant pipe 61 branches a part of the refrigerant sent from the outdoor expansion valve 38 to the indoor expansion valves 41 and 51 from a position between the outdoor heat exchanger 23 and the subcooler 25. A first branch pipe 64 connected in this manner, and a first junction pipe 65 connected to the suction side of the compressor 21 so as to return from the outlet of the bypass refrigerant pipe side of the subcooler 25 to the suction side of the compressor 21 And a bypass expansion valve 62 as a communication pipe expansion mechanism for adjusting the flow rate of the refrigerant flowing through the first bypass refrigerant pipe 61. Here, the bypass expansion valve 62 is an electric expansion valve. Thereby, the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 is cooled by the refrigerant flowing through the first bypass refrigerant pipe 61 after being depressurized by the bypass expansion valve 62 in the supercooler 25. . That is, the capacity control of the subcooler 25 is performed by adjusting the opening degree of the bypass expansion valve 62. Further, as will be described later, the first bypass refrigerant pipe 61 is a communication pipe that connects a portion of the refrigerant circuit 10 between the liquid side shut-off valve 26 and the outdoor expansion valve 38 and a portion on the suction side of the compressor 21. It is supposed to function as well. In the present embodiment, the first bypass refrigerant pipe 61 is provided so as to branch the refrigerant from a position between the outdoor expansion valve 38 and the subcooler 25. However, the first bypass refrigerant pipe 61 is not limited to this, and the outdoor expansion is provided. What is necessary is just to be provided so that a refrigerant | coolant may be branched from the position between the valve 38 and the liquid side closing valve 26. FIG.

  In the present embodiment, the expansion tank 73 is provided with a second bypass refrigerant pipe 71 for releasing the volume expansion of the liquid refrigerant inside the liquid refrigerant pipe portion. The second bypass refrigerant pipe 71 is a part of the liquid refrigerant pipe part between the supercooler 25 and the liquid side shut-off valve and a part between the suction side of the accumulator 24 and the gas refrigerant communication pipe 7 (hereinafter referred to as gas refrigerant pipe). This is a bypass pipe connecting the The second bypass refrigerant pipe 71 is provided with an expansion tank 73 and a second branch pipe 75 which is a flow path on the inlet side of the expansion tank 73, so that the liquid refrigerant pipe portion and the expansion tank 73 are in communication with each other. The first on-off valve 72 as an opening / closing mechanism that can be brought into a state and the second merging pipe 76 that is a flow path on the outlet side of the expansion tank 73 are in communication with the gas refrigerant pipe portion and the expansion tank 73. A second opening / closing valve 74 is provided as an opening / closing mechanism that can be turned on or off. Here, the 1st on-off valve 72 and the 2nd on-off valve consist of electromagnetic valves. As a result, when the first on-off valve 72 is opened, the refrigerant in the liquid refrigerant piping portion can be received in the expansion tank 73. When the liquid refrigerant in the liquid refrigerant piping portion expands due to, for example, a temperature rise, Can be absorbed by the expansion tank 73. Although not employed in the present embodiment, the expansion tank 73 may be replaced with a pipe having a volume capable of absorbing the expanded refrigerant.

  The liquid side shutoff valve 26 and the gas side shutoff valve 27 are valves provided at connection ports with external devices and pipes (specifically, the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7). The liquid side shut-off valve 26 is disposed downstream of the outdoor expansion valve 38 and upstream of the liquid refrigerant communication pipe 6 in the refrigerant flow direction in the refrigerant circuit 10 during the cooling operation (in the present embodiment). Is connected to the subcooler 25), and it is possible to block the passage of the refrigerant. The gas side closing valve 27 is connected to the four-way switching valve 22.

  The outdoor unit 2 is provided with various sensors in addition to the liquid level detection sensor 39 described above. Specifically, in the outdoor unit 2, a suction pressure sensor 29 that detects the suction pressure of the compressor 21, a discharge pressure sensor 30 that detects the discharge pressure of the compressor 21, and a suction temperature of the compressor 21 are detected. An intake temperature sensor 31 and a discharge temperature sensor 32 that detects the discharge temperature of the compressor 21 are provided. A liquid pipe temperature sensor 35 that detects the temperature of the refrigerant (that is, the liquid pipe temperature) is provided at the outlet of the subcooler 25 on the main refrigerant circuit side. The first merging pipe 65 of the first bypass refrigerant pipe 61 is provided with a bypass temperature sensor 63 for detecting the temperature of the refrigerant flowing through the outlet of the subcooler 25 on the bypass refrigerant pipe side. An outdoor temperature sensor 36 for detecting the temperature of the outdoor air flowing into the unit (that is, the outdoor temperature) is provided on the outdoor air inlet side of the outdoor unit 2. In the present embodiment, the suction temperature sensor 31, the discharge temperature sensor 32, the liquid pipe temperature sensor 35, the outdoor temperature sensor 36, and the bypass temperature sensor 63 are composed of thermistors. The outdoor unit 2 also has an outdoor control unit 37 that controls the operation of each unit constituting the outdoor unit 2. The outdoor control unit 37 includes a microcomputer provided to control the outdoor unit 2, an inverter circuit that controls the memory and the motor 21 m, and the like. Control signals and the like can be exchanged with 47 and 57 via the transmission line 8a. That is, the control part 8 which performs operation control of the whole air conditioning apparatus 1 is comprised by the indoor side control parts 47 and 57, the outdoor side control part 37, and the transmission line 8a which connects between the control parts 37, 47 and 57. Yes.

  As shown in FIG. 3, the control unit 8 is connected so that it can receive detection signals of various sensors 29 to 32, 35, 36, 39, 44 to 46, 54 to 56, 63, and these Various devices and valves 21, 22, 28, 38, 41, 43, 51, 53, 62, 72, 74 are connected based on the detection signals of Moreover, various data are stored in the memory which comprises the control part 8, for example, the appropriateness | suitableness of the refrigerant circuit 10 of the air conditioning apparatus 1 for every property in which the piping length etc. after being constructed in the building were considered Refrigerant amount data and the like are stored. Then, the control unit 8 reads out these data when performing the automatic refrigerant charging operation and the refrigerant leakage detection operation, which will be described later, and fills the refrigerant circuit 10 with an appropriate amount of refrigerant, or the appropriate refrigerant amount data. The presence or absence of refrigerant leakage is judged by comparing with the above. In addition to the appropriate refrigerant amount data (appropriate refrigerant amount Z), the memory of the control unit 8 stores liquid pipe determined refrigerant amount data (liquid pipe determined refrigerant amount Y) and outdoor heat exchanger collected refrigerant amount data (outdoor The heat exchange collected refrigerant amount X) is stored, and the relationship of Z = X + Y is satisfied. Here, the liquid pipe determined refrigerant amount Y extends from the downstream side of the outdoor heat exchanger 23 described later to the indoor expansion valves 41 and 51 via the outdoor expansion valve 38, the subcooler 25, and the liquid refrigerant communication pipe 6. The part from the first branch pipe 64 to the bypass expansion valve 62 and the part from the second branch pipe 75 to the first on-off valve (hereinafter referred to as a liquid refrigerant pipe part) is sealed with liquid refrigerant at a constant temperature. This is the amount of refrigerant fixed to the liquid refrigerant piping portion when the operation is performed. The outdoor heat exchange collected refrigerant amount X is a refrigerant amount obtained by subtracting the liquid pipe fixed refrigerant amount Y from the appropriate refrigerant amount Z. Further, the memory of the control unit 8 stores a relational expression that can calculate the amount of refrigerant accumulated from the outdoor expansion valve 38 to the outdoor heat exchanger 23 based on the liquid level data of the outdoor heat exchanger 23. Here, FIG. 3 is a control block diagram of the air conditioner 1.

<Refrigerant communication piping>
Refrigerant communication pipes 6 and 7 are refrigerant pipes constructed on site when the air conditioner 1 is installed at an installation location such as a building, and installation conditions such as the installation location and a combination of an outdoor unit and an indoor unit. Those having various lengths and tube diameters are used. For this reason, for example, when a new air conditioner is installed, the air conditioner 1 is filled with an appropriate amount of refrigerant according to the installation conditions such as the length and pipe diameter of the refrigerant communication pipes 6 and 7. There is a need to.

  As described above, the refrigerant circuit 10 of the air conditioner 1 is configured by connecting the indoor refrigerant circuits 10a and 10b, the outdoor refrigerant circuit 10c, and the refrigerant communication pipes 6 and 7. The air conditioner 1 of the present embodiment is operated by switching the cooling operation and the heating operation by the four-way switching valve 22 by the control unit 8 including the indoor side control units 47 and 57 and the outdoor side control unit 37. In addition, the devices of the outdoor unit 2 and the indoor units 4 and 5 are controlled in accordance with the operation load of the indoor units 4 and 5.

(2) Operation | movement of an air conditioning apparatus Next, operation | movement of the air conditioning apparatus 1 of this embodiment is demonstrated.

  As an operation mode of the air conditioner 1 of the present embodiment, a normal operation mode for controlling the components of the outdoor unit 2 and the indoor units 4 and 5 according to the operation load of the indoor units 4 and 5, and an air conditioner When the test operation is performed after the installation of the component 1 or the like, the refrigerant automatic charging operation mode in which the refrigerant circuit 10 is charged with an appropriate amount of refrigerant, and the test operation including such an automatic refrigerant charging operation are terminated and the normal operation is performed. There is a refrigerant leakage detection operation mode in which the presence or absence of refrigerant leakage from the refrigerant circuit 10 is determined after starting the operation.

  Hereinafter, the operation | movement in each operation mode of the air conditioning apparatus 1 is demonstrated.

<Normal operation mode>
First, the cooling operation in the normal operation mode will be described with reference to FIG.

  During the cooling operation, the four-way switching valve 22 is in the state indicated by the solid line in FIG. 1 (cooling operation state), that is, the discharge side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23 and the compressor 21 Is in a state of being connected to the gas side of the indoor heat exchangers 42 and 52 via the gas side closing valve 27 and the gas refrigerant communication pipe 7. Here, the outdoor expansion valve 38, the bypass expansion valve 62, and the second on-off valve 74 are fully opened, and the liquid side closing valve 26 and the gas side closing valve 27 are also opened. Further, the first on-off valve 72 is closed.

  When the compressor 21, the outdoor fan 28, and the indoor fans 43 and 53 are operated in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant. Thereafter, the high-pressure gas refrigerant is sent to the outdoor heat exchanger 23 via the four-way switching valve 22, exchanges heat with the outdoor air supplied by the outdoor fan 28, and condenses to form a high-pressure liquid refrigerant. Become. Then, the high-pressure liquid refrigerant passes through the outdoor expansion valve 38 and flows into the supercooler 25, and is further cooled by performing heat exchange with the refrigerant flowing through the first bypass refrigerant pipe 61 to be in a supercooled state. . At this time, a part of the high-pressure liquid refrigerant condensed in the outdoor heat exchanger 23 is branched into the first bypass refrigerant pipe 61, decompressed by the bypass expansion valve 62, and then returned to the suction side of the compressor 21. Here, a part of the refrigerant passing through the bypass expansion valve 62 is evaporated by being depressurized to near the suction pressure of the compressor 21. Then, the refrigerant flowing from the outlet of the bypass expansion valve 62 of the first bypass refrigerant pipe 61 toward the suction side of the compressor 21 passes through the subcooler 25 and passes from the outdoor heat exchanger 23 on the main refrigerant circuit side to the room. Heat exchange is performed with the high-pressure liquid refrigerant sent to the units 4 and 5.

  Then, the high-pressure liquid refrigerant in a supercooled state is sent to the indoor units 4 and 5 via the liquid-side closing valve 26 and the liquid refrigerant communication pipe 6.

  The high-pressure liquid refrigerant sent to the indoor units 4 and 5 is reduced to near the suction pressure of the compressor 21 by the indoor expansion valves 41 and 51 to become a low-pressure gas-liquid two-phase refrigerant and the indoor heat exchanger. The heat is exchanged with indoor air in the indoor heat exchangers 42 and 52 and evaporated to become a low-pressure gas refrigerant.

  The low-pressure gas refrigerant is sent to the outdoor unit 2 via the gas refrigerant communication pipe 7 and flows into the accumulator 24 via the gas-side closing valve 27 and the four-way switching valve 22. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21. As described above, in the air conditioner 1, the outdoor heat exchanger 23 is used as a refrigerant condenser to be compressed in the compressor 21, and the indoor heat exchangers 42 and 52 are condensed after being condensed in the outdoor heat exchanger 23. It is possible to perform at least a cooling operation that functions as an evaporator of the refrigerant sent through the refrigerant communication pipe 6 and the indoor expansion valves 41 and 51.

  Here, the refrigerant distribution state of the refrigerant circuit 10 during the cooling operation in the normal operation mode is as follows. As shown in FIG. 4, the refrigerant is in the liquid state (the hatched portion in FIG. 4), the gas-liquid The two-phase state (lattice hatched portion in FIG. 4) and the gas state (hatched hatched portion in FIG. 4) are distributed and distributed. Specifically, from the vicinity of the outlet of the outdoor heat exchanger 23 via the outdoor expansion valve 38, the indoor expansion valve 41, via the part on the main refrigerant circuit side of the subcooler 25 and the liquid refrigerant communication pipe 6, The portion up to 51 and the portion on the upstream side of the bypass expansion valve 62 of the first bypass refrigerant pipe 61 are filled with liquid refrigerant. And an intermediate part of the outdoor heat exchanger 23, a part of the first bypass refrigerant pipe 61 on the upstream side of the bypass expansion valve 62, a part of the subcooler 25 on the bypass refrigerant pipe side near the inlet, Portions near the inlets of the heat exchangers 42 and 52 are filled with a gas-liquid two-phase refrigerant. In addition, a part from the middle part of the indoor heat exchangers 42 and 52 to the inlet of the outdoor heat exchanger 23 via the gas refrigerant communication pipe 7 and the compressor 21, a part near the inlet of the outdoor heat exchanger 23, And the part by the side of bypass refrigerant piping of subcooler 25 until it merges from the middle part to the suction side of compressor 21 of the 1st bypass refrigerant pipe 61 is filled with the refrigerant of the gas state. . Here, FIG. 4 is a schematic diagram showing a state of the refrigerant flowing in the refrigerant circuit 10 in the cooling operation.

  In the cooling operation in the normal operation mode, the refrigerant is distributed in the refrigerant circuit 10 in such a distribution. However, in the refrigerant amount determination operation in the refrigerant automatic charging operation mode and the refrigerant leakage detection operation mode described later, The distribution is a collection of liquid refrigerant in the liquid refrigerant communication pipe 6 and the outdoor heat exchanger 23 (see FIG. 6).

  Next, the heating operation in the normal operation mode will be described.

  During the heating operation, the four-way switching valve 22 is in the state indicated by the broken line in FIG. 1 (heating operation state), that is, the discharge side of the compressor 21 is exchanged indoors via the gas side closing valve 27 and the gas refrigerant communication pipe 7. The compressors 42 and 52 are connected to the gas side, and the suction side of the compressor 21 is connected to the gas side of the outdoor heat exchanger 23. The degree of opening of the outdoor expansion valve 38 is adjusted so as to reduce the refrigerant flowing into the outdoor heat exchanger 23 to a pressure at which the refrigerant can evaporate in the outdoor heat exchanger 23 (that is, evaporation pressure). . Further, the liquid side closing valve 26 and the gas side closing valve 27 are in an open state. The opening degree of the indoor expansion valves 41 and 51 is adjusted so that the degree of supercooling of the refrigerant at the outlets of the indoor heat exchangers 42 and 52 becomes constant at the target value of the degree of supercooling. In the present embodiment, the degree of refrigerant supercooling at the outlets of the indoor heat exchangers 42 and 52 is calculated by converting the discharge pressure of the compressor 21 detected by the discharge pressure sensor 30 into a saturation temperature value corresponding to the condensation temperature. It is detected by subtracting the refrigerant temperature value detected by the liquid side temperature sensors 44 and 54 from the saturation temperature value of the refrigerant. Although not adopted in this embodiment, a temperature sensor for detecting the temperature of the refrigerant flowing in each indoor heat exchanger 42, 52 is provided, and a refrigerant temperature value corresponding to the condensation temperature detected by this temperature sensor. May be subtracted from the refrigerant temperature value detected by the liquid side temperature sensors 44 and 54 to detect the degree of supercooling of the refrigerant at the outlets of the indoor heat exchangers 42 and 52. The second on-off valve 74 is fully open, and the first on-off valve 72 and the bypass expansion valve 62 are closed.

  When the compressor 21, the outdoor fan 28, and the indoor fans 43, 53 are operated in the state of the refrigerant circuit 10, the low-pressure gas refrigerant is sucked into the compressor 21 and compressed to become a high-pressure gas refrigerant. It is sent to the indoor units 4 and 5 via the valve 22, the gas side closing valve 27 and the gas refrigerant communication pipe 7.

  The high-pressure gas refrigerant sent to the indoor units 4 and 5 is condensed by exchanging heat with the indoor air in the outdoor heat exchangers 42 and 52 to become a high-pressure liquid refrigerant, and then the indoor expansion valve 41. , 51, the pressure is reduced according to the valve opening degree of the indoor expansion valves 41, 51.

  The refrigerant that has passed through the indoor expansion valves 41 and 51 is sent to the outdoor unit 2 via the liquid refrigerant communication pipe 6 and further reduced in pressure via the liquid side closing valve 26, the subcooler 25, and the outdoor expansion valve 38. Then, it flows into the outdoor heat exchanger 23. The low-pressure gas-liquid two-phase refrigerant flowing into the outdoor heat exchanger 23 exchanges heat with the outdoor air supplied by the outdoor fan 28 to evaporate into a low-pressure gas refrigerant. And flows into the accumulator 24. Then, the low-pressure gas refrigerant that has flowed into the accumulator 24 is again sucked into the compressor 21.

  The operation control in the normal operation mode as described above is performed by the control unit 8 (more specifically, the indoor side control units 47 and 57 and the outdoor side control functioning as the operation control means for performing the normal operation including the cooling operation and the heating operation. Transmission line 8a) connecting between the unit 37 and the control units 37, 47, 57.

<Automatic refrigerant charging operation mode>
Next, the refrigerant automatic charging operation mode performed during the trial operation will be described with reference to FIGS. Here, FIG. 5 is a flowchart of the refrigerant quantity determination operation. FIG. 6 is a schematic diagram showing the state of the refrigerant flowing in the refrigerant circuit 10 in the refrigerant quantity determination operation. FIG. 7 is a diagram schematically showing the inside of the heat exchanger main body 23a and the header 23b of FIG. 2, and is a diagram showing how refrigerant is accumulated in the outdoor heat exchanger 23 in the refrigerant amount determination operation.

  The refrigerant automatic charging operation mode is an operation mode performed at the time of a test operation after installation of the components of the air conditioner 1, and an appropriate amount of refrigerant according to the volumes of the liquid refrigerant communication pipe 6 and the gas refrigerant communication pipe 7 Is automatically filled into the refrigerant circuit 10.

  First, the liquid side shut-off valve 26 and the gas side shut-off valve 27 of the outdoor unit 2 are opened, and the refrigerant circuit 10 is filled with the refrigerant filled in the outdoor unit 2 in advance.

  Next, an operator who performs the automatic refrigerant charging operation connects a refrigerant cylinder for additional charging to the refrigerant circuit 10 (for example, the suction side of the compressor 21) and starts charging.

  When the operator issues a command to start the automatic refrigerant charging operation to the control unit 8 directly or with a remote controller (not shown) or the like, the control unit 8 causes the steps S1 to S6 shown in FIG. It is accompanied by the process.

  First, in step S1, liquid temperature constant control is performed in the cooling operation state, and device control is basically performed so as to perform the same operation as the cooling operation in the normal operation mode described above. However, the point that the liquid temperature constant control is performed is different from the cooling operation in the normal operation mode. In this liquid temperature constant control, condensing pressure control and liquid pipe temperature control are performed. In the condensation pressure control, the air volume of the outdoor air supplied to the outdoor heat exchanger 23 by the outdoor fan 28 is controlled so that the condensation pressure of the refrigerant in the outdoor heat exchanger 23 becomes constant. Since the condensing pressure of the refrigerant in the condenser changes more greatly than the influence of the outdoor temperature, the air volume of the indoor air supplied from the outdoor fan 28 to the outdoor heat exchanger 23 is controlled by the motor 28m. Thereby, the condensing pressure of the refrigerant in the outdoor heat exchanger 23 becomes constant, and the state of the refrigerant flowing in the condenser is stabilized. And between the outdoor heat exchanger 23 and the indoor expansion valves 41 and 51, the outdoor expansion valve 38, the part on the main refrigerant circuit side of the subcooler 25, the flow path including the liquid refrigerant communication pipe 6, and the outdoor heat exchanger A high-pressure liquid refrigerant flows through the flow path from 23 to the bypass expansion valve 62 of the first bypass refrigerant pipe 61. Therefore, the refrigerant pressure in the portion from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 and the bypass expansion valve 62 is also stabilized. In the condensation pressure control of this embodiment, the discharge pressure of the compressor 21 detected by the discharge pressure sensor 30 is used as the condensation pressure. Although not adopted in this embodiment, a temperature sensor that detects the temperature of the refrigerant flowing in the outdoor heat exchanger 23 is provided, and the refrigerant temperature value corresponding to the condensation temperature detected by this temperature sensor is set to the condensation pressure. It may be used for condensing pressure control in conversion. In the liquid pipe temperature control, unlike the superheat control in the cooling operation in the normal operation mode described above, the supercooler 25 is controlled so that the temperature of the refrigerant sent from the supercooler 25 to the indoor expansion valves 41 and 51 is constant. Control ability. More specifically, in the liquid pipe temperature control, the refrigerant temperature detected by the liquid pipe temperature sensor 35 provided at the outlet of the subcooler 25 on the main refrigerant circuit side is constant at the liquid pipe temperature target value. Further, the opening degree of the bypass expansion valve 62 of the first bypass refrigerant pipe 61 is adjusted. Thereby, the refrigerant density in the refrigerant pipe including the liquid refrigerant communication pipe 6 extending from the outlet on the main refrigerant circuit side of the subcooler 25 to the indoor expansion valves 41 and 51 is stabilized.

  In step S2, it is determined whether or not the liquid temperature has reached a constant by performing the liquid temperature constant control in step S1. If it is determined that the liquid temperature is constant, the process proceeds to step S3. If it is determined that the liquid temperature is not yet constant, the liquid temperature constant control in step S1 is continued. become. Then, when the liquid temperature is controlled to be constant by the constant liquid temperature control, the liquid refrigerant communication pipe from the outlet on the main refrigerant circuit side of the subcooler 25 to the indoor expansion valves 41 and 51 in the hatched portion in FIG. The inside of the refrigerant pipe including 6 is stably sealed by the liquid refrigerant having a constant temperature.

  Thereby, in step S3 which will be described later, the indoor expansion valves 41 and 51 and the outdoor expansion valve 38 are disposed in the refrigerant circuit 10 between the indoor expansion valves 41 and 51 including the liquid refrigerant communication pipe 6 and the outdoor expansion valve 38. Before the liquid refrigerant is contained, the temperature of the refrigerant sent from the outdoor heat exchanger 23 to the indoor expansion valves 41 and 51 through the liquid refrigerant communication pipe 6 is adjusted to be constant by the subcooler 25 and fixed to the liquid refrigerant pipe portion. The liquid pipe determined refrigerant amount Y, which is the refrigerant amount, is maintained.

  Next, in step S3, the indoor expansion valves 41 and 51 are fully closed, the bypass expansion valve 62 is fully closed, and the outdoor expansion valve 38 is fully closed, so that the liquid in the refrigerant circuit 10 is liquid. Liquid refrigerant is sealed in a portion between the indoor expansion valves 41 and 51 and the outdoor expansion valve 38 including the refrigerant communication pipe 6 (liquid pipe closing control). As a result, while the refrigerant amount of the liquid pipe determined refrigerant amount Y is maintained, the circulation of the refrigerant is interrupted, and the liquid refrigerant of the accurate liquid pipe determined refrigerant amount Y considering the refrigerant temperature is supplied to the refrigerant circuit 10. Of these, it can be contained in a portion between the indoor expansion valves 41 and 51 and the outdoor expansion valve 38 including the liquid refrigerant communication pipe 6. The operation of the compressor 21 and the outdoor fan 28 is continued even after the expansion valves 38, 41, 51 are fully closed. As a result, as shown in FIG. 6, the refrigerant condensed in the outdoor heat exchanger 23 functioning as a condenser is not circulated in the refrigerant circuit 10 by the outdoor expansion valve 38. In the exchanger 23, the refrigerant 23 is cooled and condensed by the outdoor air supplied by the outdoor fan 28, on the upstream side of the outdoor expansion valve 38 in the refrigerant circuit 10 such as the outdoor heat exchanger 23, and in the compressor 21. It will gradually accumulate in the downstream part. As a result, the refrigerant in the refrigerant circuit 10 is concentrated in a portion of the refrigerant circuit 10 upstream of the outdoor expansion valve 38 and downstream of the compressor 21. More specifically, as shown in FIG. 7, the refrigerant that has been condensed into a liquid state accumulates from the upstream side of the outdoor expansion valve 38 into the outdoor heat exchanger 23. As described above, since the liquid refrigerant is confined in the portion between the indoor expansion valves 41 and 51 including the liquid refrigerant communication pipe 6 and the outdoor expansion valve 38 in the refrigerant circuit 10, In the cooling operation, the amount of liquid refrigerant accumulated from the upstream side of the outdoor expansion valve 38 to the inside of the outdoor heat exchanger 23 is prevented from becoming excessive.

  In step S4, the second on-off valve 74 is closed and the first on-off valve is opened. As a result, the refrigerant can flow between the liquid refrigerant pipe portion and the expansion tank 73 in a state where the liquid pipe determined refrigerant amount Y is maintained. Even when the volume of the liquid refrigerant confined in the liquid refrigerant pipe portion expands due to a temperature rise or the like, the expansion tank 73 can absorb the volume of the expansion. As a result, as shown in FIG. 6, the expansion tank 73 fills the volume of the expansion tank 73 by evaporating a part of the liquid refrigerant (filled hatched portion) and the liquid refrigerant, so that the gas-liquid two-phase (lattice hatched portion) is filled. ) Will be mixed with the refrigerant in the state.

  Next, in step S <b> 5, the liquid level of the refrigerant accumulated in the outdoor heat exchanger 23 is detected by the liquid level detection sensor 39. Here, the liquid level detection sensor 39 detects the boundary between the region where the refrigerant exists in the gas state and the region where the refrigerant exists in the liquid state as the liquid level. Thus, the outdoor level heat exchange from the outdoor expansion valve 38 is performed by substituting the liquid level height h obtained by the liquid level detection sensor 39 (see FIG. 7) into the relational expression stored in the memory of the control unit 8. The amount of refrigerant accumulated over the vessel 23 is calculated.

  Next, in step S6, it is determined whether or not the refrigerant amount calculated in step S5 described above has reached the outdoor heat exchange collected refrigerant amount X stored in the memory of the control unit 8. If the outdoor heat exchange collected refrigerant amount X has not been reached, the process returns to step S5, the refrigerant circuit 10 is continuously charged with the refrigerant, and it is determined that the outdoor heat exchange collected refrigerant amount X has been reached. If so, the charging of the refrigerant into the refrigerant circuit 10 is terminated. Accordingly, the liquid level detection sensor 39 can detect the state quantity related to the refrigerant amount collected in the upstream side of the outdoor expansion valve 38 and the downstream side of the compressor 21 in the refrigerant circuit 10. It is possible to determine the amount of refrigerant, and it is possible to determine an appropriate amount of refrigerant while simplifying the conditions for determining the amount of refrigerant.

  Thus, in the air conditioning apparatus 1, as described above, the liquid temperature constant control is performed in step S1, the liquid pipe closing control is performed in step S3, and the liquid refrigerant pipe portion and the expansion tank are further controlled in step S4. 73, the refrigerant compressed in the compressor 21 is condensed in the outdoor heat exchanger 23 and stored in the upstream portion of the outdoor expansion valve 38 including the outdoor heat exchanger 23. Is done. And the state quantity regarding the refrigerant | coolant amount which exists in the upstream of the outdoor expansion valve 38 by the process of above-mentioned step S5, S6 is detected, and it is set as the state quantity regarding the refrigerant | coolant amount which the liquid level detection sensor 39 detected in the refrigerant | coolant amount determination driving | operation. Based on this, it is possible to determine whether or not the amount of refrigerant in the refrigerant circuit 10 is appropriate.

  These processes such as control are performed by an operation control unit that performs the refrigerant amount determination operation, and a control unit 8 that functions as a refrigerant amount determination unit that determines the suitability of the refrigerant amount in the refrigerant circuit 10 (more specifically, the chamber This is performed by the transmission line 8a) connecting the inner control units 47, 57, the outdoor control unit 37, and the control units 37, 47, 57.

  In the present embodiment, by performing liquid temperature constant control (particularly liquid pipe temperature control), a portion of the refrigerant circuit 10 between the use side expansion mechanism including the liquid refrigerant communication pipe 6 and the blocking mechanism is provided. Since a constant amount of refrigerant is always contained, the length of the liquid refrigerant communication pipe 6 constituting the refrigerant circuit 10 is long, and the amount of refrigerant contained in the liquid refrigerant communication pipe 6 is relatively large by the process of step S3. Even when there are a large number, it is possible to contain an accurate amount of refrigerant in the liquid refrigerant communication pipe 6, so that the refrigerant circuit 10 is located upstream of the outdoor expansion valve 38 and downstream of the compressor 21. Although the liquid level detection sensor 39 can suppress the influence on the refrigerant quantity in the portion and can stably detect the state quantity related to the refrigerant quantity, the liquid refrigerant communication pipe constituting the refrigerant circuit 10 When the amount of refrigerant contained in the liquid refrigerant communication pipe 6 is small by the process of step S2, the refrigerant circuit 10 is upstream of the outdoor expansion valve 38 and downstream of the compressor 21. Since the influence on the amount of the refrigerant in this portion is small, it is not always necessary to perform constant liquid temperature control (particularly, liquid pipe temperature control), and the processing in step S2 may be omitted.

<Refrigerant leak detection operation mode>
Next, the refrigerant leak detection operation mode will be described.

  The refrigerant leakage detection operation mode is substantially the same as the refrigerant automatic charging operation mode except that it involves a refrigerant charging operation, and only the differences will be described.

  In the present embodiment, the refrigerant leakage detection operation mode is, for example, periodically (such as a time zone in which air conditioning is not required during holidays or midnight), and the refrigerant does not leak to the outside from the refrigerant circuit 10 due to an unexpected cause. This is an operation performed when detecting whether or not.

  In the refrigerant leakage detection operation, the same processing as that in the above-described refrigerant automatic charging operation is performed.

  That is, in the refrigerant circuit 10, the liquid temperature constant control is performed in the cooling operation state or the heating operation state, and after the liquid temperature becomes constant, the indoor expansion valves 41 and 51 and the liquid side closing valve 26 are fully closed, and the liquid pipe The fixed refrigerant amount Y is fixed (see step S1 to step S3). Further, along with the operation of the indoor expansion valves 41 and 51 and the liquid side closing valve 26, the bypass expansion valve 62 is fully opened, the outdoor expansion valve 38 is fully closed, and the cooling operation is continued, thereby the outdoor heat exchanger. The refrigerant quantity determination operation for storing the liquid refrigerant in 23 is performed.

  Here, if the detection liquid level height h by the liquid level detection sensor 39 is maintained unchanged for a predetermined time, the liquid level height h at that time is expressed by the relational expression stored in the memory of the control unit 8. By substituting, the determination liquid refrigerant amount X ′ accumulated from the outdoor expansion valve 38 to the outdoor heat exchanger 23 is calculated. Here, whether or not the refrigerant leaks in the refrigerant circuit 10 is determined based on whether or not the appropriate refrigerant amount Z is obtained by adding the liquid pipe determined refrigerant amount Y to the calculated determination liquid refrigerant amount X ′.

  In addition, after acquiring the data of the liquid level height h without changing the liquid level height h for a predetermined time, the operation of the compressor 21 is immediately stopped. Thereby, the refrigerant leakage detection operation is terminated.

  The determination of refrigerant leakage detection is not limited to the method of calculating the above-described determination liquid refrigerant amount X ′. For example, a reference liquid level height H corresponding to the optimal refrigerant amount is calculated in advance, and this value is calculated. By storing in the memory of the control unit 8, the detected liquid level height h is directly compared with the reference liquid level height H as an index without the need to calculate the determination liquid refrigerant amount X ′. By doing so, the refrigerant leakage detection may be performed.

(3) Features of the air conditioner The air conditioner 1 of the present embodiment has the following features.

  In the air conditioner 1 of this embodiment, after the outdoor expansion valve 38 is closed as described above, the liquid refrigerant is contained in the liquid refrigerant pipe portion, and the volume expansion (for example, the ambient temperature) An expansion tank 73 is provided so as to absorb (for example, changes in conditions). During the constant liquid temperature control, the first on-off valve 72 provided in the second branch pipe 75 connecting one end of the expansion tank 73 and the liquid refrigerant pipe portion is closed, and the other end of the expansion tank 73 and the gas are connected. The 2nd on-off valve 74 provided in the 2nd junction pipe 76 which connects the gas refrigerant | coolant piping part between the refrigerant | coolant communication piping 6 to the compressor 21 is opened. Then, after the liquid temperature constant control is completed and the liquid pipe closing control is performed, the first on-off valve 72 is opened and the second on-off valve 74 is closed. In other words, the liquid temperature constant control is performed so that the inside of the liquid refrigerant pipe portion is stably sealed by the liquid refrigerant at a constant temperature, and the liquid pipe fixed refrigerant amount Y fixed inside the liquid refrigerant pipe portion is determined. In a maintained state, after the liquid pipe determined refrigerant amount Y is sealed in the liquid refrigerant pipe part by the liquid pipe closing control, the first on-off valve 72 is opened to allow the liquid refrigerant pipe part and the expansion tank 73 to communicate with each other. By closing the second on-off valve 74, the liquid pipe determined refrigerant amount Y sealed by the liquid pipe closing control is contained in the portion where the inside of the liquid refrigerant pipe portion and the inside of the expansion tank 73 are combined.

  Therefore, in the air conditioner 1 of the present invention, even after the liquid pipe closing control, for example, even when the volume of the liquid refrigerant inside the liquid refrigerant pipe portion is changed due to a change in ambient temperature conditions, the expansion tank 73 can absorb the expansion. For this reason, it can prevent that a liquid refrigerant piping part is damaged when the liquid refrigerant inside a liquid refrigerant piping part expand | swells. Further, in the case where a safety device such as a high-pressure control valve 77 for escaping the high pressure in the liquid refrigerant piping portion is provided as in the present embodiment, in the same case, from the liquid refrigerant piping portion, Since the refrigerant can be contained without escaping, a certain amount of liquid refrigerant can be fixed and secured, and a more appropriate amount of refrigerant can be determined.

(4) Modification 1
In the present embodiment, the liquid refrigerant pipe portion and the expansion tank 73 are connected by the second branch pipe 75 branched from the pipe between the supercooler 25 and the liquid side shut-off valve 26, and the second branch pipe 75 is connected. By switching the first on-off valve 72 provided in the liquid crystal, the liquid refrigerant pipe portion and the expansion tank 73 are switched between a communication state and a shut-off state. The first bypass refrigerant pipe 61 as a cooling source is connected to the expansion tank 73, and the bypass expansion valve 62 is used as an opening / closing mechanism that can connect or disconnect the liquid refrigerant pipe portion and the expansion tank 73. You may do it (refer FIG. 8). That is, in the first modification, the expansion tank 73 is connected using the first bypass refrigerant pipe 61, and in this case, the first merging pipe 65 that is the pipe on the outlet side of the expansion tank 73 is connected to the first joining pipe 65. A second opening / closing valve 74 is provided as an opening / closing mechanism capable of bringing the gas refrigerant piping portion and the expansion tank 73 into communication or blocking. In addition, let the heat source unit in this case be the outdoor unit 2a.

(5) Modification 2
In the present embodiment, the expansion tank 73 serving as an expansion absorption mechanism capable of absorbing the volume expansion of the liquid refrigerant in the liquid refrigerant pipe portion is connected to the liquid refrigerant pipe portion by the second bypass refrigerant pipe 71, but this is not limitative. Alternatively, the accumulator 24 may be used as the expansion absorption mechanism (see FIG. 9). In this case, in the gas refrigerant pipe part, the part before the first joining pipe 65 of the first bypass refrigerant pipe 61 joins the main refrigerant circuit and the part between the accumulator 24 and the compressor are bypassed. A third bypass refrigerant pipe 81 is provided. In addition, a third on-off valve capable of opening and closing the flow path of the pipe between the location where the first merging pipe 65 of the first bypass refrigerant pipe 61 joins the main refrigerant circuit and the location where the third bypass refrigerant pipe 81 is branched. 82, a fourth on-off valve 83 capable of opening and closing the flow path of the third bypass refrigerant pipe 81 is provided, and the flow path of the pipe to the location where the third bypass refrigerant circuit 81 merges on the outlet side of the accumulator 24 is provided. A fifth on-off valve that can be opened and closed is provided. Further, an oil drain pipe 85 capable of discharging the refrigeration oil and / or refrigerant from the bottom of the accumulator 24 is connected to a pipe on the suction side of the compressor 21, and a flow path of the oil drain pipe 85 can be opened and closed. A six on-off valve 86 is provided. Here, the third on-off valve 82, the fourth on-off valve 83, the fifth on-off valve 84, and the sixth on-off valve 86 are electromagnetic valves. The third on-off valve 82 may be a check valve instead of a solenoid valve. The heat source unit in this case is referred to as an outdoor unit 2b.

  In the outdoor unit 2b of the second modification, the refrigerant amount determination operation and the determination process of the appropriateness of the refrigerant amount are the same from step S1 to step S3 in the present embodiment, and the process of step S4 is different. Here, step S7 is used instead of step S4.

  In step S7, the bypass expansion valve 62, the third on-off valve 82, and the fifth on-off valve 84 are closed, and the fourth on-off valve 83 is opened. As a result, the liquid refrigerant piping portion and the accumulator 24 can be in communication with each other while the liquid pipe determined refrigerant amount Y is maintained, and the gas refrigerant piping portion and the accumulator 24 can be shut off. It can be used as an expansion absorption mechanism that absorbs the volume expansion of the liquid refrigerant inside the refrigerant pipe portion. Further, when the liquid refrigerant is accumulated in the accumulator 24 after the liquid pipe closing control, the refrigerant amount determination operation is performed more quickly by opening the sixth on-off valve 86 and discharging the liquid refrigerant from the accumulator 24. It becomes possible. During normal operation, the third on-off valve 82 and the fifth on-off valve 84 are in an open state, and the fourth on-off valve 83 is in a closed state.

(6) Modification 3
In the present embodiment, the expansion tank 73 independent as the expansion absorption mechanism is provided inside the outdoor unit 2, but not limited to this, the indoor heat exchangers 42 and 52 may be used as the expansion absorption mechanism. Good (see FIG. 10). In this case, the indoor units 4a and 5a are provided with a seventh on-off valve 48 and an eighth on-off valve 58 in the gas-side piping of the indoor heat exchangers 42 and 52, respectively. Here, the seventh on-off valve 48 and the eighth on-off valve 58 are electromagnetic valves.

  In the third modification, the refrigerant amount determination operation and the determination process of the appropriateness of the refrigerant amount are the same from step S1 to step S3 in the present embodiment, and the processes after step S4 are different. Here, step S8 is used instead of step S4.

  In step S8, it is determined whether or not the liquid refrigerant is accumulated in the indoor heat exchangers 42 and 52 based on the detection values detected by the liquid side temperature sensors 44 and 54 and the gas side temperature sensors 45 and 55. If it is determined that the liquid refrigerant has not accumulated in the indoor heat exchangers 42 and 52, the seventh on-off valve 48 and the eighth on-off valve 58 are closed, and the indoor expansion valves 41 and 51 are opened. Thereby, it is possible to make the refrigerant flowable between the liquid refrigerant piping portion and the indoor heat exchangers 42 and 52 while maintaining the liquid pipe determined refrigerant amount Y. In the third modification, the seventh on-off valve 48 and the eighth on-off valve 58 are provided in the indoor units 4 and 5 as means for shutting off the indoor heat exchangers 42 and 52 from the gas side piping. Not limited to this, an electromagnetic valve may be provided in the pipe between the gas closing valve 27 on the outdoor unit 2 side and the accumulator 24.

(Second Embodiment)
In the above-described first embodiment and the air conditioner 1 in the modification example, the case where there is one outdoor unit has been described as an example, but the present invention is not limited to this, and for example, this embodiment shown in FIG. Like the air conditioner 101 of the form, a plurality of (in the present embodiment, two) outdoor units 2 may be provided in parallel. Here, the outdoor unit 2 and the indoor units 4 and 5 have the same configurations as the outdoor unit 2 and the indoor units 4 and 5 in the first embodiment described above, and thus description thereof is omitted here.

  In the air conditioning apparatus 101 of the present embodiment, detection by the liquid level detection sensor 39 is individually performed in each outdoor unit 2 in the automatic refrigerant charging operation and the refrigerant leakage detection operation, and the outdoor heat exchanger collected refrigerant amount X is Although it is different in that the determination as to whether or not the refrigerant has accumulated is made with respect to the refrigerant amount in the refrigerant circuit 110 including all the outdoor units 2, basically, the refrigerant circuit 10 in the first embodiment described above This is the same as the determination of the suitability of the refrigerant amount. Moreover, in the air conditioning apparatus 101 of this embodiment, you may apply the structure similar to the modification 1-3 of the above-mentioned 1st Embodiment.

(Third embodiment)
In the air conditioning apparatuses 1 and 101 in the first and second embodiments described above and the modifications thereof, the case where the present invention is applied to the configuration in which the cooling operation and the heating operation can be switched is described as an example, but the present invention is not limited thereto. For example, like the air conditioner 201 of this embodiment shown in FIG. 12, for example, a cooling operation is performed for a certain air-conditioned space, and a heating operation is performed for another air-conditioned space. In addition, the present invention may be applied to a configuration capable of simultaneous cooling and heating according to the requirements of indoor air-conditioned spaces in which the indoor units 4 and 5 are installed.

  The air conditioner 201 of the present embodiment mainly includes indoor units 4 and 5 as a plurality of (here, two) use units, an outdoor unit 202 as a heat source unit, and refrigerant communication pipes 6, 7 a, and 7 b. And.

  The outdoor units 4 and 5 are connected to the outdoor unit 202 via the liquid refrigerant communication pipe 6, the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe 7b as gas refrigerant communication pipes, and the connection units 204 and 205. The refrigerant circuit 210 is configured with the outdoor unit 202. In addition, since the indoor units 4 and 5 are the same structures as the indoor units 4 and 5 in the above-mentioned 1st Embodiment, description is abbreviate | omitted here.

  The outdoor unit 202 mainly constitutes a part of the refrigerant circuit 210 and includes an outdoor refrigerant circuit 210c. The outdoor refrigerant circuit 210c mainly includes a compressor 21, a three-way switching valve 222, an outdoor heat exchanger 23 as a heat source side heat exchanger, a liquid level detection sensor 39 as a refrigerant detection mechanism, and a second cutoff mechanism. Alternatively, an outdoor expansion valve 38 as a heat source side expansion mechanism, an accumulator 24, a supercooler 25 as a temperature adjustment mechanism, a first bypass refrigerant pipe 61 as a cooling source and a communication pipe of the supercooler 25, and a first It has a liquid side closing valve 26, a suction gas side closing valve 27a, a discharge gas side closing valve 27b, a high / low pressure communication pipe 233, a high pressure cutoff valve 234, and an outdoor fan 28 as a cutoff mechanism. Here, the other devices and valves other than the three-way switching valve 222, the suction gas side closing valve 27a, the discharge gas side closing valve 27b, the high and low pressure communication pipe 233, and the high pressure cutoff valve 234 are the same as those in the first embodiment. Since it is the structure similar to the apparatus and valves of the outdoor unit 2 in, description is abbreviate | omitted.

  The three-way switching valve 222 connects the discharge side of the compressor 21 and the gas side of the outdoor heat exchanger 23 when the outdoor heat exchanger 23 functions as a condenser (hereinafter referred to as a condensing operation state). When the heat exchanger 23 functions as an evaporator (hereinafter referred to as an evaporation operation state), the inside of the outdoor refrigerant circuit 210c is connected so that the suction side of the compressor 21 and the gas side of the outdoor heat exchanger 23 are connected. It is a valve for switching the flow path of the refrigerant. A discharge gas refrigerant communication pipe 7b is connected between the discharge side of the compressor 21 and the three-way switching valve 222 via a discharge gas side closing valve 27b. Thereby, the high-pressure gas refrigerant compressed and discharged in the compressor 21 can be supplied to the indoor units 4 and 5 regardless of the switching operation of the three-way switching valve 222. An intake gas refrigerant communication pipe 7a is connected to the intake side of the compressor 21 via an intake gas side closing valve 27a. As a result, the low-pressure gas refrigerant returning from the indoor units 4 and 5 can be returned to the suction side of the compressor 21 regardless of the switching operation of the three-way switching valve 222. The high / low pressure communication pipe 233 includes a refrigerant pipe connecting a position between the discharge side of the compressor 21 and the three-way switching valve 222 and the discharge gas refrigerant communication pipe 7b, and a suction side of the compressor 21 and a suction gas. This is a refrigerant pipe that communicates with a refrigerant pipe that connects to the refrigerant communication pipe 7a, and has a high-low pressure communication valve 233a that can block the passage of the refrigerant. Accordingly, the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe 7b can be brought into communication with each other as necessary. The high-pressure shut-off valve 234 is provided in a refrigerant pipe connecting the position between the discharge side of the compressor 21 and the three-way switching valve 222 and the discharge gas refrigerant communication pipe 7b. The high-pressure gas refrigerant discharged from the machine 21 can be blocked from being sent to the discharge gas refrigerant communication pipe 7b. In the present embodiment, the high-pressure shut-off valve 234 has a high-low pressure communication pipe 233 connected to a refrigerant pipe connecting the position between the discharge side of the compressor 21 and the three-way switching valve 222 and the discharge gas refrigerant communication pipe 7b. It is arranged on the discharge side of the compressor 21 with respect to the position. In the present embodiment, the high / low pressure communication valve 233a and the high pressure cutoff valve 234 are electromagnetic valves. In the present embodiment, the three-way switching valve 222 is used as a mechanism for switching between the condensing operation state and the evaporation operation state. You may use what comprised the solenoid valve.

  Also, the outdoor unit 202 is provided with various sensors and the outdoor control unit 37, and these are also the configurations of the various sensors and the outdoor control unit 37 of the outdoor unit 2 in the first embodiment described above. Since it is the same as that, description is abbreviate | omitted.

  The indoor units 4 and 5 are connected so that the gas side of the indoor heat exchangers 42 and 52 can be switched to the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe 7b via the connection units 204 and 205. The connection units 204 and 205 mainly include cooling / heating switching valves 204a and 205a. The cooling / heating switching valves 204a and 205a connect the gas side of the indoor heat exchangers 42 and 52 of the indoor units 4 and 5 and the intake gas refrigerant communication pipe 7a when the indoor units 4 and 5 perform cooling operation ( When the indoor units 4 and 5 perform the heating operation, the gas side of the indoor heat exchangers 42 and 52 of the indoor units 4 and 5 and the discharge gas refrigerant communication pipe 7b are connected. It is a valve that functions as a switching mechanism that switches between a state (hereinafter referred to as a heating operation state). In the present embodiment, as the mechanism for switching between the cooling operation state and the heating operation state, cooling / heating switching valves 204a and 205a including three-way switching valves are used, but the present invention is not limited to this. You may use what comprised the four-way switching valve, the some solenoid valve, etc.

  With such a configuration of the air conditioner 201, the indoor units 4 and 5 can perform a so-called simultaneous cooling and heating operation, for example, a heating operation of the indoor unit 5 while the indoor unit 4 is performing a cooling operation. It has become.

  In the air conditioning apparatus 201 that can be operated simultaneously with cooling and heating, the three-way switching valve 222 is set in a condensing operation state, the outdoor heat exchanger 23 is functioned as a refrigerant condenser, and the cooling and heating switching valves 204a and 205a are set in a cooling operation state. Thus, by causing the indoor heat exchangers 42 and 52 to function as a refrigerant evaporator, it is possible to perform the refrigerant amount determination operation and determination of the appropriateness of the refrigerant amount in the same manner as the air conditioner 1 in the first embodiment described above.

  However, since the air conditioner 201 of the present embodiment has the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe 7b as the gas refrigerant communication pipe 7, the air refrigerant apparatus 201 is high in the cooling operation in the normal operation mode. By making the low-pressure communication valve 233a fully closed and the high-pressure shut-off valve 234 fully open, the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe 7b are not in communication, and the compressor 21 When the high-pressure gas refrigerant discharged from the refrigerant can be sent to the discharge gas refrigerant communication pipe 7b, the high-pressure gas refrigerant accumulated in the discharge gas refrigerant communication pipe 7b is condensed in the outdoor heat exchanger 23. It becomes impossible to accumulate in the upstream portion of the outdoor expansion valve 38 including the outdoor heat exchanger 23, which adversely affects the determination accuracy of the refrigerant amount in the refrigerant circuit 10. Therefore, in the refrigerant amount determination operation, the intake gas refrigerant communication pipe 7a and the discharge gas refrigerant communication pipe are set by fully closing the high / low pressure communication valve 233a and fully opening the high pressure shut-off valve 234. 7 b is communicated, and the high-pressure gas refrigerant discharged from the compressor 21 is blocked from being sent to the discharge gas refrigerant communication pipe 7 b. As a result, the pressure of the refrigerant in the discharge gas refrigerant communication pipe 7b becomes the same as the pressure of the refrigerant in the suction gas refrigerant communication pipe 7a, and no refrigerant accumulates in the discharge gas refrigerant communication pipe 7b. The high-pressure gas refrigerant accumulated in the communication pipe 7b can be condensed in the outdoor heat exchanger 23 and accumulated in the upstream portion of the outdoor expansion valve 38 including the outdoor heat exchanger 23. This makes it difficult to adversely affect the determination accuracy of the refrigerant amount.

  As described above, in the air conditioner 201 of the present embodiment, in the refrigerant amount determination operation, the intake gas refrigerant communication pipe is set by fully closing the high / low pressure communication valve 233a and fully opening the high pressure shut-off valve 234. 7a and the discharge gas refrigerant communication pipe 7b are in communication with each other, and the operation of blocking the high-pressure gas refrigerant discharged from the compressor 21 from being sent to the discharge gas refrigerant communication pipe 7b is performed. Although it is different from the air conditioner 1 in FIG. 1, it is basically the same as the determination of the suitability of the refrigerant amount in the refrigerant circuit 10 in the first embodiment. Moreover, in the air conditioning apparatus 201 of this embodiment, you may apply the structure similar to the modification 1-3 of the above-mentioned 1st Embodiment, and like the air conditioning apparatus 101 of 2nd Embodiment. In addition, a configuration in which a plurality of outdoor units 202 are connected may be employed.

(Other embodiments)
As mentioned above, although embodiment of this invention and its modification were demonstrated based on drawing, specific structure is not restricted to these embodiment and its modification, It changes in the range which does not deviate from the summary of invention. Is possible.

  For example, the present invention is applied not to the air conditioners 1 and 101 that can be switched between the cooling operation and the heating operation or the air conditioner 201 that can simultaneously operate the cooling operation and the heating operation, but also to an air conditioner dedicated to the cooling operation. Is possible.

  The air conditioner and the refrigerant amount determination method according to the present invention can prevent the piping from being damaged, and have the effect of accurately determining whether or not the refrigerant amount is appropriate. This is useful as an air conditioner and refrigerant amount determination operation that accurately determines whether or not the refrigerant amount is appropriate while preventing the pipe from being damaged in the air conditioner and refrigerant amount determination operation for determining whether the refrigerant amount is appropriate.

It is a schematic structure figure of the air harmony device concerning a 1st embodiment of the present invention. It is the schematic of an outdoor heat exchanger. It is a control block diagram of an air conditioning apparatus. It is a schematic diagram which shows the state of the refrigerant | coolant which flows through the inside of the refrigerant circuit in air_conditionaing | cooling operation. It is a flowchart of a refrigerant | coolant amount determination driving | operation. It is a schematic diagram which shows the state of the refrigerant | coolant which flows through the refrigerant circuit in a refrigerant | coolant amount determination driving | operation. It is the figure which showed typically the inside of the heat exchanger main body of FIG. 2, and a header, Comprising: It is a figure which shows a mode that a refrigerant | coolant accumulates in an outdoor heat exchanger in refrigerant | coolant amount determination driving | operation. It is a schematic block diagram of the air conditioning apparatus concerning the modification 1 of 1st Embodiment of this invention. It is a schematic block diagram of the air conditioning apparatus concerning the modification 2 of 1st Embodiment of this invention. It is a schematic block diagram of the air conditioning apparatus concerning the modification 3 of 1st Embodiment of this invention. It is a schematic block diagram of the air conditioning apparatus concerning 2nd Embodiment. It is a schematic block diagram of the air conditioning apparatus concerning 3rd Embodiment.

Explanation of symbols

1, 1a, 1b, 1c, 101, 201 Air conditioner 2, 202 Outdoor unit (heat source unit)
4, 5, 4a, 5a Indoor unit (Usage unit)
6 Liquid refrigerant communication pipe 7, 7a, 7b Gas refrigerant communication pipe 10, 110, 210 Refrigerant circuit 21 Compressor 22 Four-way switching valve (switching mechanism)
23 Outdoor heat exchanger (heat source side heat exchanger)
24 Accumulator (Expansion absorption mechanism)
25 Supercooler 38 Outdoor expansion valve (second shut-off mechanism)
39 Liquid level detection sensor (refrigerant detection mechanism)
41, 51 Indoor expansion valve (use side expansion mechanism)
42, 52 Indoor heat exchanger (use side heat exchanger)
48 7th open / close valve (second shutoff mechanism)
58 Eighth on-off valve (second shut-off mechanism)
62 Bypass expansion valve (first opening / closing mechanism)
64 1st branch pipe (1st flow path)
65 1st merge pipe (2nd flow path)
72 1st on-off valve (1st on-off mechanism)
73 Expansion tank (Expansion absorption mechanism)
74 Second on-off valve (second on-off mechanism)
75 Second branch pipe (first flow path)
76 Second merge pipe (second flow path)
84 Fifth open / close valve (second open / close mechanism)

Claims (7)

Use having a heat source unit (2,202) having a compressor (21) and a heat source side heat exchanger (23), a use side expansion mechanism (41,51), and a use side heat exchanger (42,52). A unit (4, 5), a liquid refrigerant communication pipe (6) and a gas refrigerant communication pipe (7, 7a, 7b) connecting the heat source unit and the utilization unit, and the heat source side heat exchanger It is possible to perform at least a cooling operation in a cooling operation state in which the condenser on the compressor to be compressed in the compressor and the utilization side heat exchanger function as an evaporator on the refrigerant to be condensed in the heat source side heat exchanger. A refrigerant circuit (10, 110, 210),
A shut-off mechanism that is arranged downstream of the heat source side heat exchanger and upstream of the liquid refrigerant communication pipe in the flow direction of the refrigerant in the refrigerant circuit when performing the cooling operation, and can block the passage of the refrigerant ( 38)
A refrigerant detection mechanism (39) that is arranged on the upstream side of the shutoff valve in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and detects the amount of refrigerant existing on the upstream side of the shutoff valve;
An expansion absorption mechanism (at least connected to a liquid refrigerant pipe portion between the use-side expansion mechanism including the liquid refrigerant communication pipe and the shut-off mechanism, and capable of absorbing a volume expansion of the refrigerant inside the liquid refrigerant pipe portion ( 24, 73)
An air conditioner (1, 1a, 1b, 101, 201) comprising: In the cooling operation state, a liquid temperature constant control is performed so that the refrigerant temperature of the liquid refrigerant pipe portion becomes a constant value, a liquid pipe closing control for closing the shut-off mechanism and the use side expansion mechanism is performed, Operation control means for performing liquid refrigerant storage control for storing liquid refrigerant in a portion upstream of the shut-off mechanism;
Refrigerant amount determination means for determining the suitability of the refrigerant amount in the refrigerant circuit based on the state amount related to the refrigerant amount detected by the refrigerant detection mechanism in the liquid refrigerant storage control;
The air conditioner (1, 1a, 1b, 101, 201) according to claim 1, further comprising: Provided in a first flow path (64, 75) that connects one end of the expansion absorption mechanism and the liquid refrigerant piping portion, and makes the liquid refrigerant piping portion and the expansion absorption mechanism communicate or shut off. A first opening / closing mechanism (62, 72) capable of
Provided in a second flow path (65, 76) that connects the other end of the expansion absorption mechanism and a gas refrigerant piping portion between the gas refrigerant communication pipe and the compressor, and the gas refrigerant piping portion and the expansion A second opening / closing mechanism (74, 84) capable of bringing the absorption mechanism into communication or blocking;
Further comprising
The operation control means closes the first opening / closing mechanism and opens the second opening / closing mechanism during the liquid temperature constant control, and opens the first opening / closing mechanism after the liquid pipe closing control. 2 Close the opening and closing mechanism,
The air conditioning apparatus (1, 1a, 1b, 101, 201) according to claim 2. A subcooler (25) capable of cooling the refrigerant condensed in the heat source side heat exchanger during operation in the cooling operation state;
The first opening / closing mechanism (62) functions as an expansion mechanism that depressurizes the refrigerant flowing to the subcooler,
The first flow path (64) is a cooling source side of the subcooler that cools the refrigerant sent from the heat source side heat exchanger to the use side expansion mechanism with the refrigerant depressurized by the first opening / closing mechanism. Including
The air conditioner (1a, 1b) according to claim 3. The expansion absorption mechanism (24) is provided on the suction side of the compressor and functions as an accumulator capable of separating the refrigerant into liquid refrigerant and gas refrigerant and supplying only the gas refrigerant to the compressor.
The air conditioner (1b) according to claim 3 or 4. Use having a heat source unit (2,202) having a compressor (21) and a heat source side heat exchanger (23), a use side expansion mechanism (41,51), and a use side heat exchanger (42,52). A unit (4a, 5a), a liquid refrigerant communication pipe (6) and a gas refrigerant communication pipe (7) connecting the heat source unit and the utilization unit, and compressing the heat source side heat exchanger in the compressor A refrigerant circuit capable of performing at least a cooling operation in a cooling operation state in which the use side heat exchanger functions as a refrigerant evaporator to be condensed in the heat source side heat exchanger. 10) and
A first cutoff that is arranged downstream of the heat source side heat exchanger and upstream of the liquid refrigerant communication pipe in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and can block passage of the refrigerant. A mechanism (38);
A refrigerant detection mechanism (39) that is arranged on the upstream side of the shutoff valve in the refrigerant flow direction in the refrigerant circuit when performing the cooling operation, and detects the amount of refrigerant existing on the upstream side of the shutoff valve;
A second blocking mechanism (48, 58) provided between the use side heat exchanger and the compression mechanism and capable of blocking the passage of the refrigerant, and in the cooling operation state, the refrigerant temperature in the liquid refrigerant pipe portion is constant. Liquid refrigerant storage that performs liquid temperature constant control to control the liquid temperature, performs liquid pipe closing control to close the shut-off mechanism and the use-side expansion mechanism, and stores liquid refrigerant in a portion upstream of the shut-off mechanism Operation control means for controlling,
Refrigerant amount determination means for determining the suitability of the refrigerant amount in the refrigerant circuit based on the state amount related to the refrigerant amount detected by the refrigerant detection mechanism in the liquid refrigerant storage control;
Liquid refrigerant determination means for determining whether liquid refrigerant is present in the use side heat exchanger;
With
The operation control means is performing the liquid refrigerant storage control, and after the liquid refrigerant determination means determines that the liquid refrigerant is not present in the use-side heat exchanger, the second control mechanism is closed to Open the side expansion mechanism,
Air conditioner (1c). Use having a heat source unit (2,202) having a compressor (21) and a heat source side heat exchanger (23), a use side expansion mechanism (41,51), and a use side heat exchanger (42,52). A unit (4, 5), a liquid refrigerant communication pipe (6) and a gas refrigerant communication pipe (7, 7a, 7b) connecting the heat source unit and the utilization unit, and the heat source side heat exchanger It is possible to perform at least a cooling operation in a cooling operation state in which the condenser on the compressor to be compressed in the compressor and the utilization side heat exchanger function as an evaporator on the refrigerant to be condensed in the heat source side heat exchanger. In an air conditioner having a simple refrigerant circuit (10, 110, 210), a refrigerant amount determination method for determining suitability of the refrigerant amount in the refrigerant circuit,
A shut-off mechanism (38) that is arranged on the downstream side of the heat source side heat exchanger and the upstream side of the liquid refrigerant communication pipe in the flow direction of the refrigerant in the refrigerant circuit during the cooling operation and can shut off the refrigerant passage. ) And a liquid temperature constant control for controlling the refrigerant temperature of the liquid refrigerant pipe portion between the use side expansion mechanism to be a constant value,
An expansion absorption mechanism (at least connected to a liquid refrigerant pipe portion between the use-side expansion mechanism including the liquid refrigerant communication pipe and the shut-off mechanism, and capable of absorbing a volume expansion of the refrigerant inside the liquid refrigerant pipe portion ( 24, 73) is provided in a first flow path (64, 75) that connects one end of the liquid refrigerant pipe portion and the liquid refrigerant pipe portion, and is capable of allowing the refrigerant to flow into and out of the expansion absorption mechanism from the liquid refrigerant pipe portion. 1 open / close mechanism (62, 72) is closed during the liquid temperature constant control, and the other end of the expansion absorption mechanism and a gas refrigerant pipe portion between the gas refrigerant communication pipe and the compressor, The second opening / closing mechanism (74, 84) provided in the second flow path (65, 76) for connecting the gas and allowing the refrigerant to flow into and out of the expansion absorption mechanism from the gas refrigerant piping portion is at a constant liquid temperature. Open during control,
Perform liquid tube closing control to close the blocking mechanism and the user-side expansion mechanism,
After the liquid pipe closing control, the first opening / closing mechanism is opened, the second opening / closing mechanism is closed,
Perform liquid refrigerant storage control to store liquid refrigerant in the upstream portion of the shut-off mechanism,
A refrigerant detection mechanism (39) that is disposed upstream of the blocking mechanism in the refrigerant flow direction in the refrigerant circuit during the cooling operation and detects a state quantity related to the amount of refrigerant existing upstream of the blocking mechanism. By detecting a state quantity related to the refrigerant quantity existing on the upstream side of the shut-off mechanism,
Determining whether or not the refrigerant amount in the refrigerant circuit is appropriate based on a state quantity related to the refrigerant amount detected by the refrigerant detection mechanism in the liquid refrigerant storage control;
Refrigerant amount determination method.

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