WO2007069624A1

WO2007069624A1 - Air conditioner

Info

Publication number: WO2007069624A1
Application number: PCT/JP2006/324806
Authority: WO
Inventors: Tadafumi Nishimura; Shinichi Kasahara
Original assignee: Daikin Industries, Ltd.
Priority date: 2005-12-16
Filing date: 2006-12-13
Publication date: 2007-06-21
Also published as: US20090314017A1; JP2007163106A; AU2006324541B2; AU2006324541A1; EP1965150A1; CN101331366A; EP1965150A4; CN101331366B; KR20080071601A; EP1965150B1; ES2636912T3

Abstract

Prediction error in quantity of refrigerant due to difference in solubility of refrigerant into oil is minimized by eliminating refrigerant liquefied into refrigerating machine oil in a compression machine mechanism. The air conditioner (1) comprises a refrigerant circuit (7), means (8a-8c) for judging refrigerant, and operation controllers (6a-6c). The refrigerant circuit includes heat source units (2a-2c), refrigerant communication pipings (4, 5), expansion mechanisms (31a, 31b, ...), and utilization units (29a-29c, 3a, 3b, ...). The refrigerant communication piping is connected with the heat source units and the utilization units. The heat source unit has compression mechanisms (21a-21c) and heat source side heat exchangers (24a-24c). The means for judging liquefied refrigerant can judge the situation of liquefied refrigerant in the compression mechanism. When liquefied refrigerant is detected in the compression mechanism before operation for judging the quantity of refrigerant in the circuit is performed, the operation controller performs an operation for eliminating the liquefied refrigerant.

Description

Air conditioner

Technical field

TECHNICAL FIELD [0001] The present invention relates to a refrigerant circuit for an air conditioner and an air conditioner including the refrigerant circuit.

[0002] As a refrigerant leakage detection device of a conventional refrigeration apparatus, there is one disclosed in Patent Document 1. In this refrigerant leak detection device, the condensed refrigerant temperature and the evaporated refrigerant temperature adjusting means adjust the condensed refrigerant temperature and the evaporated refrigerant temperature to a constant value, and the output signal and set value of the discharged refrigerant temperature detector are adjusted. A refrigerant leak detection operation for detecting refrigerant leak in the refrigeration cycle is performed by a temperature difference calculation means for calculating a temperature difference by comparison. Therefore, by adjusting the condensing refrigerant temperature flowing through the condenser and the evaporating refrigerant temperature flowing through the evaporator to a constant value, the discharge refrigerant temperature under an appropriate amount of refrigerant is set as a set value, and the set value and the discharge refrigerant temperature are set. Compared with the output signal of the temperature detector, if it is lower than the set value, it is determined that the refrigerant leaks and V, and if it is higher than the set value, it is determined that the refrigerant leaks!

Patent Document 1: Japanese Patent Laid-Open No. 11-212292

Disclosure of the invention

Problems to be solved by the invention

[0003] However, in the technique of Patent Document 1, since the amount of refrigerant that dissolves in the refrigeration machine oil in the compression mechanism increases at low outside air temperature, the prediction error of the refrigerant amount may increase. In particular, when the internal oil temperature is low immediately after starting the compressor, or when only some of the compressors are driven during the refrigerant leak detection operation with multiple compressors, the refrigerant leak detection error increases. . An object of the present invention is to eliminate the stagnation of the refrigerant with respect to the refrigerating machine oil in the compression mechanism, and to minimize the prediction error of the refrigerant amount due to the difference in the solubility of the refrigerant in the oil.

Means for solving the problem

[0004] An air conditioner according to a first aspect of the present invention includes a refrigerant circuit, a refrigerant stagnation judging means, and an operation control device. The refrigerant circuit includes a heat source unit, a refrigerant communication pipe, an expansion mechanism, Circuit including a unit for use. The heat source unit has a compression mechanism and a heat source side heat exchange. A heat source unit is connected to the refrigerant communication pipe. The usage unit has usage side heat exchange and is connected to the refrigerant communication pipe. The refrigerant stagnation determining means can determine whether or not the refrigerant is sleeping in the compressor. When the operation control device performs the refrigerant amount determination operation for determining the refrigerant amount in the refrigerant circuit, if the refrigerant stagnation determining means determines in advance that the refrigerant is stagnation in the compression mechanism, the refrigerant stagnation Perform refrigerant stagnation elimination operation to eliminate the problem.

In this air conditioner, when the refrigerant amount determination operation is performed, it is determined in advance by the refrigerant stagnation determination means whether or not the refrigerant has stagnation in the refrigerating machine oil in the compression mechanism. Then, when the refrigerant stagnation determining means determines that the refrigerant has stagnated in the refrigerating machine oil in the compression mechanism, the operation control device performs the refrigerant stagnation elimination operation.

Therefore, in this air conditioner, the refrigerant amount determination operation can be performed after eliminating the stagnation of the refrigerant with respect to the refrigeration oil in the compression mechanism. For this reason, during the refrigerant quantity determination operation, the refrigerant quantity dissolved in the refrigerating machine oil in the compression mechanism can be reduced as much as possible, and the prediction error of the refrigerant quantity can be reduced. As a result, the refrigerant stagnation with respect to the refrigerating machine oil in the compression mechanism can be eliminated during the refrigerant quantity judgment operation, so that more accurate refrigerant quantity judgment operation can be performed.

[0005] 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, wherein the refrigerant stagnation determining means makes a determination based on the temperature in the compression mechanism.

In this air conditioner, the determination by the refrigerant stagnation determination means is made based on the temperature in the compression mechanism. When the temperature in the compression mechanism is low, the refrigerant easily stagnates in the refrigeration oil. Therefore, when the temperature in the compression mechanism is low, it is possible to determine that the cooling medium has stagnated in the refrigerating machine oil in the compression mechanism. For this reason, based on the temperature in the compression mechanism, it is possible to determine whether or not the refrigerant is stagnant in the refrigerating machine oil in the compression mechanism.

[0006] An air conditioner according to a third aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the refrigerant stagnation determining means makes a determination based on the outside air temperature.

In this air conditioner, the determination by the refrigerant stagnation determination means is made based on the outside air temperature. When the temperature in the compression mechanism is low, the refrigerant easily stagnates in the refrigeration oil. Gatsutsu Since the outside air temperature can be measured, the temperature in the compression mechanism can be predicted. For this reason, when it can be predicted that the temperature in the compression mechanism is low, it is possible to determine that the refrigerant has stagnated in the refrigeration oil in the compression mechanism. As a result, it is possible to determine whether or not the refrigerant has stagnation with respect to the refrigerating machine oil in the compression mechanism.

[0007] An air conditioner according to a fourth aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the refrigerant stagnation determining means makes a determination based on weather information.

In this air conditioner, the determination by the refrigerant stagnation determination means is made based on weather information obtained via a network connected to the refrigerant stagnation determination means. Therefore, the weather information ability can also acquire the outside air temperature, and the temperature in the compression mechanism can be predicted. For this reason, when it can be predicted that the temperature in the compression mechanism is low, it is possible to determine that the refrigerant has stagnated in the refrigerating machine oil in the compression mechanism. As a result, it is possible to determine whether or not the refrigerant has stagnation with respect to the refrigerating machine oil in the compression mechanism.

[0008] An air conditioner according to a fifth aspect of the present invention is the air conditioner according to the first aspect of the present invention, wherein the refrigerant stagnation determining means is based on a refrigerant stagnation period in which it is predicted that the refrigerant is likely to stagnate in the compression mechanism. Make a decision.

In this air conditioner, the determination by the refrigerant stagnation determination means is made based on a preset period. When the temperature in the compression mechanism is low, the refrigerant is likely to stagnate in the refrigeration oil. This determination is made by providing a period during which the temperature in the compression mechanism is expected to be low.

Therefore, the user can predict the stagnation of the refrigerant without measuring the temperature in the compression mechanism by setting a period during which the temperature in the compression mechanism is predicted to be low. As a result, it is possible to determine whether or not the refrigerant has stagnation with respect to the refrigerating machine oil in the compression mechanism. In addition, it is not necessary to install a temperature sensor, etc., which can reduce production costs.

[0009] An air conditioner according to a sixth aspect of the present invention is the air conditioner according to any one of the first to fifth aspects of the invention, wherein the operation control unit operates the compression mechanism as a refrigerant stagnation elimination operation for a first predetermined time. Control to drive.

In this air conditioner, the refrigerant stagnation elimination operation is performed by driving the compressor for a first predetermined time. Warm-up operation. Therefore, in this refrigerant stagnation elimination operation, the inside of the compression mechanism can be warmed by operating the compressor for the first predetermined time. For this reason, it is possible to eliminate the stagnation of the refrigerant with respect to the refrigerating machine oil in the compressor premises.

[0010] An air conditioner according to a seventh aspect of the present invention is the air conditioner according to any one of the first to sixth aspects of the present invention, wherein there are a plurality of heat source units.

In this air conditioner, there are a plurality of heat source units. Therefore, the heat source units in the system can be rotated and driven one unit at a time for a certain period of time, so that the load is not biased to one unit even at low loads, and the life of the entire system can be extended.

[0011] An air conditioner according to an eighth invention is the air conditioner according to any of the first to seventh inventions, wherein the compression mechanism has a plurality of compressors.

In this air conditioner, the compression mechanism has a plurality of compressors. Therefore, since the capacity of the compression mechanism can be changed by controlling the number of compressors, it becomes possible to continue operation of all the heat source units even when the operating load of the units used decreases, and the refrigerant circuit It is possible to prevent accumulation of oil as much as possible. In addition, even if one of the compressors fails, the remaining compressors can handle them. For this reason, complete shutdown of air conditioning can be avoided.

[0012] An air conditioner according to a ninth invention is the air conditioner according to the eighth invention, wherein the refrigerant stagnation elimination operation is an operation that drives at least a compressor that is not driven during the refrigerant quantity determination operation. is there.

In this air conditioner, when there are a plurality of compressors, the compressor driven by the refrigerant amount determination can be sufficiently warmed during the refrigerant amount determination operation. Drive the compressor not driven by. Therefore, it is not necessary to drive all the compressors, so that the energy used can be reduced. Moreover, the time required for the refrigerant stagnation elimination operation can be shortened.

[0013] An air conditioner according to a tenth aspect of the present invention is the air conditioner according to the eighth aspect of the present invention, wherein the refrigerant control stagnation elimination operation is performed for a second predetermined time period during which the operation control device drives all the compressors one by one The operation is performed sequentially at intervals of. In this air conditioner, when there are a plurality of compressors, all the compressors are rotated one by one and driven for a second predetermined time. And, since the cooling operation is performed at low outside air temperature during the refrigerant stagnation elimination operation, it is difficult to operate all the compressors at once because of the low load. For this reason, it is possible to drive all the compressors in advance by operating each unit for the second predetermined time.

[0014] An air conditioner according to an eleventh aspect of the present invention is the air conditioner according to the first aspect of the present invention, further comprising a heater that warms the compressor mechanism. The refrigerant stagnation elimination operation is an operation in which the compression mechanism is heated by the heater.

In this air conditioner, the refrigerant stagnation elimination operation is performed by warming the compression mechanism with a heater. Therefore, it is possible to eliminate the stagnation of the refrigerant without driving the compressor. This eliminates the need to drive the compressor during the refrigerant stagnation elimination operation, so that the compressor drive time can be shortened and the life of the compressor can be extended.

[0015] An air conditioner according to a twelfth aspect of the present invention is the air conditioner according to any of the first to eleventh aspects of the invention, wherein the operation control device further performs an oil return operation immediately after the refrigerant stagnation elimination operation. . The oil return operation is an operation for returning the oil accumulated in the refrigerant circuit into the compression mechanism.

In this air conditioner, an oil return operation is further performed after the refrigerant stagnation elimination operation. Therefore, by further performing the oil return operation, it is possible to return the oil accumulated in the refrigerant circuit to the compressor structure. For this reason, more accurate refrigerant quantity determination operation becomes possible.

[0016] An air conditioner according to a thirteenth aspect of the present invention is the air conditioner according to the twelfth aspect of the present invention, wherein the oil return operation is performed so that the refrigerant flow rate in the pipe of the refrigerant flowing through the refrigerant circuit is not less than a predetermined flow rate. It is driving to control.

In this air conditioner, the oil return operation is an operation for controlling the refrigerant flow rate in the pipe to be equal to or higher than a predetermined flow rate. Therefore, it is possible to reliably return the oil accumulated in the refrigerant circuit into the compression mechanism. For this reason, a more accurate refrigerant quantity determination operation can be performed. The invention's effect

[0017] In the air conditioner according to the first aspect of the present invention, the refrigerant amount determination operation can be performed after eliminating the stagnation of the refrigerant with respect to the refrigerating machine oil in the compression mechanism. For this reason, during the refrigerant quantity determination operation, the refrigerant quantity dissolved in the refrigerating machine oil in the compression mechanism can be reduced as much as possible, and the prediction error of the refrigerant quantity can be reduced. As a result, the refrigerant stagnation with respect to the refrigerating machine oil in the compression mechanism can be eliminated during the refrigerant quantity judgment operation, so that more accurate refrigerant quantity judgment operation can be performed.

In the air conditioner according to the second aspect of the present invention, when the temperature in the compression mechanism is low, it is possible to determine that the refrigerant is stagnant with respect to the refrigerating machine oil in the compression mechanism. Therefore, it is possible to determine whether or not the refrigerant has stagnated in the refrigerating machine oil in the compression mechanism based on the temperature in the compression mechanism.

In the air conditioner according to the third aspect of the invention, the temperature inside the compression mechanism can be predicted because the outside air temperature can be measured. For this reason, when it can be predicted that the temperature in the compression mechanism is low, it is possible to determine if the refrigerant has stagnated in the refrigeration oil in the compression mechanism. As a result, it is possible to determine whether or not the refrigerant has stagnation with respect to the refrigerating machine oil in the compression mechanism.

[0018] In the air conditioner according to the fourth aspect of the invention, the weather information power can also acquire the outside air temperature, and the temperature in the compression mechanism can be predicted. Therefore, when the temperature in the compression mechanism can be predicted to be low V, it can be determined that the refrigerant has stagnated in the refrigerating machine oil in the compression mechanism. As a result, it is possible to determine whether or not the refrigerant has stagnated in the refrigerating machine oil in the compression mechanism.

In the air conditioner according to the fifth aspect of the invention, the user can predict the stagnation of the refrigerant without measuring the temperature in the compression mechanism by setting a period during which the temperature in the compression mechanism is predicted to be low. It becomes. As a result, it is possible to determine whether or not the refrigerant has stagnated in the refrigeration machine oil in the compression mechanism. In addition, since it is not necessary to install a temperature sensor, production costs can be reduced.

In the air conditioner according to the sixth aspect of the present invention, in the refrigerant stagnation elimination operation, the inside of the compression mechanism can be warmed by operating the compressor for the first predetermined time. For this reason, the compression mechanism It is possible to eliminate the stagnation of the refrigerant with respect to the internal refrigeration oil.

In the air conditioner according to the seventh aspect of the invention, the heat source units in the system can be driven by rotating each unit for a certain period of time, so that the load is not biased to one unit even at low loads, thereby extending the life of the entire system. Can do.

In the air conditioner according to the eighth aspect of the invention, since the capacity of the compression mechanism can be changed by controlling the number of compressors, even when the operating load of the utilization unit is reduced, all the heat source units are continuously operated. It is possible to prevent the accumulation of oil in the refrigerant circuit as much as possible. In addition, even if one of the compressors fails, the remaining compressors can handle them. For this reason, complete stop of air conditioning can be avoided.

[0020] In the air conditioner according to the ninth aspect of the invention, it is not necessary to drive all the compressors, so that the energy used can be reduced. In addition, the time required for the refrigerant stagnation elimination operation can be shortened.

In the air conditioner pertaining to the tenth aspect of the invention, it is possible to drive all the compressors in advance by operating each unit for a second predetermined time.

In the air conditioner according to the eleventh aspect of the present invention, it is possible to eliminate the refrigerant stagnation without driving the compressor. For this reason, it is not necessary to drive the compressor during the refrigerant stagnation elimination operation, so the drive time of the compressor can be shortened and the life of the compressor can be extended.

In the air conditioner according to the twelfth aspect of the present invention, the oil that has accumulated in the refrigerant circuit can be returned to the compression mechanism by further performing the oil return operation. For this reason, it is possible to perform a more accurate cooling amount determination operation.

[0021] In the air conditioner pertaining to the thirteenth aspect of the invention, it is possible to reliably return the oil that has accumulated in the refrigerant circuit into the compression mechanism. For this reason, a more accurate refrigerant quantity determination operation can be performed.

Brief Description of Drawings

FIG. 1 is a schematic refrigerant circuit diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of a refrigerant leakage detection operation according to the embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of an automatic refrigerant charging operation according to the embodiment of the present invention. 圆 4] A flowchart showing the flow of the refrigerant determination preparation operation according to the embodiment of the present invention. [5] A flowchart showing the flow of the refrigerant stagnation elimination operation according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a flow of oil return operation according to the embodiment of the present invention.

FIG. 7 is a schematic diagram of a weather information acquisition network of an air conditioner according to a modification of the embodiment of the present invention.

Explanation of symbols

[0023] 1 Air conditioner

2a ~ 2c Heat source unit

3a, 3b, ...

4, 5 Refrigerant communication piping

6a-6c Operation control device

8a-8c Refrigerant stagnation judgment means

21a-21c compression mechanism

22 & ~ 22c, 27 & ~ 27c, 28 & ~ 28c compressor

24a-24c Heat source side heat exchange ^^

29a ~ 29c Heat source side expansion valve

31a, 31b,… User side expansion valve

32a, 32c, ...

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] (1) Configuration of air conditioner

FIG. 1 shows a schematic refrigerant circuit diagram of the air-conditioning apparatus 1 according to the first embodiment of the present invention. The air conditioner 1 is used for air conditioning of a building or the like, and includes a plurality of (in this embodiment, three) air-cooled heat source units 2a to 2c and a number of utilization units 3a, 3b, ··· are connected in parallel to the refrigerant liquid communication pipe 4 and the refrigerant gas communication pipe 5, respectively. Here, only two units 3a and 3b are shown. Each of the plurality of heat source units 2a to 2c includes one variable capacity compressor 22a to 22c and a plurality of (in this embodiment, two) constant capacity compressors 27a to 27c, 28a to 28c. Compression mechanism 21a-21c Is provided.

Each of the usage units 3a, 3b, ... is mainly composed of the usage side expansion valves 31a, 31b, ..., 禾 lj side heat exchange 32 _& , 32b, ..., and the piping connecting them Has been. In this embodiment, the use side expansion valves 31a, 31b,... Are connected to the refrigerant liquid communication pipes 4 of the use side heat exchangers 32a, 32b,. This is an electric expansion valve connected to the side (hereinafter referred to as the liquid side). In the present embodiment, the use side heat exchangers 32a, 32b,... Are cross fin tube type heat exchangers, which are devices for exchanging heat with indoor air. In the present embodiment, the utilization units 3a, 3b,... Are provided with indoor fans (not shown) for taking in and sending out indoor air into the mute, exchange 32 _a, 32b, and a refrigerant flowing ... it is possible to heat exchange.

[0025] The heat source units 2a to 2c mainly include compression mechanisms 21a to 21c, four-way switching valves 23a to 23c, heat source side heat exchangers 24a to 24c, and liquid side closing valves 25a to 25c, respectively. The gas side closing valves 26a to 26c, the heat source side expansion valves 29a to 29c, and a pipe connecting them are configured. In the present embodiment, the heat source side expansion valves 29a to 29c are used for adjusting the refrigerant pressure, adjusting the refrigerant flow rate, etc., so as to adjust the refrigerant flow rate, etc., the refrigerant liquid communication pipe 4 side (hereinafter referred to as the liquid side) of the heat source side expansion valves 29a to 29c. It is an electric expansion valve connected to. The compression mechanisms 21a to 21c include variable capacity compressors 22a to 22c, two constant capacity compressors 27a to 27c, 28a to 28c, and an oil separator (not shown).

The compressors 22 & ~ 22c, 27 & ~ 27c, 28 & ~ 28c are devices for compressing the sucked refrigerant gas. In this embodiment, the capacity can be changed by inverter control. One compressor and two constant capacity compressors.

[0026] The four-way switching valves 23a to 23c are valves for switching the direction of the refrigerant flow when switching between the cooling operation and the heating operation. During the cooling operation, the four-way switching valves 23a to 23c exchange heat with the compression mechanisms 21a to 21c ^^ 24A～24 _C of the refrigerant gas communication pipe 5 side (hereinafter referred to as gas side) connects the suction side and the refrigerant gas communication pipe 5 of the compression mechanism 21a~21c with connecting the (four-way switching valve of Figure 1 2 3a to 23c) (Refer to solid lines 3a-23c) During heating operation, the outlets of the compression mechanisms 21a-21c and the refrigerant gas connection pipe 5 are connected and the intake side of the compression mechanisms 21a-21c and the heat source side heat exchange 24 _& It is possible to connect to the gas side of ~ 24c (refer to the broken lines of the four-way switching valves 23a to 23c in Fig. 1).

In the present embodiment, the heat source side heat exchangers 24a to 24c are cross fin tube type heat exchangers, and are devices for exchanging heat with the refrigerant using air as a heat source. In the present embodiment, the heat source units 2a to 2c are provided with outdoor fans (not shown) for taking in and sending outdoor air into the units, and the outdoor air and heat source side heat exchangers 24a to 24c. It is possible to exchange heat with the refrigerant flowing through

The liquid side closing valves 25a to 25c and the gas side closing valves 26a to 26c of the heat source units 2a to 2c are connected in parallel to the refrigerant liquid communication pipe 4 and the refrigerant gas communication pipe 5, respectively. The refrigerant liquid connection pipe 4 is connected to the liquid side of the use side heat exchangers 32a, 32b, ... of the use units 3a, 3b, ... and the liquid side of the heat source side heat exchange 24a to 24c of the heat source units 2a to 2c. Connect between and. Refrigerant gas communication pipe 5 is connected between the use side heat exchangers 32a, 32b, ... of the use units 3a, 3b, ... and the four-way switching valves 23a-23c of the heat source units 2a-2c. Is connected.

The air conditioner 1 further includes refrigerant stagnation determining means 8a to 8c and operation control devices 6a to 6c. The refrigerant stagnation determining means 8a to 8c determine whether or not the refrigerant is sleeping in the compression mechanisms 21a to 21c. When the operation control devices 6a to 6c perform the refrigerant amount determination operation for determining the refrigerant amount in the refrigerant circuit 7, if the refrigerant is already in the compression mechanisms 21a to 21c, the operation control devices 6a to 6c stagnate the refrigerant. Perform refrigerant stagnation elimination operation to eliminate. In the present embodiment, the refrigerant stagnation determining means and the operation control devices 6a to 6c are incorporated in the heat source units 2a to 2c. The operation control as described above can be performed using only the operation control device (here 6a) of the heat source unit (here 2a) set as the master unit. The operation control device (here 6b, 6c) of the heat source unit (here 2a, 2b) set as the other slave unit is the operation status of the equipment such as the compression mechanism and the detection data in various sensors. Can be sent to the operation control device 6a of the main unit, or can be functioned to issue operation and stop commands to devices such as the compression mechanism by commands from the operation control unit 6a of the main unit. . Here, temperature sensors 61a to 61c (see FIG. 1) are provided, the outside air temperature is measured by this temperature sensor, and the temperature data is transmitted to the operation control device 6a of the master unit. Then, the operation control device 6a determines whether or not to perform the refrigerant stagnation elimination operation. Make a decision.

[0028] (2) Operation of air conditioner

Next, the operation of the air conditioner 1 will be described with reference to FIG.

(Cooling operation)

First, the cooling operation will be described. During cooling operation, in all heat source units 2a to 2c, the four-way selector valves 23a to 23c are in the state indicated by the solid line in FIG. 1, that is, the discharge side of each compression mechanism 21a to 21c is the heat source side heat exchanger ^^ It is connected to the gas side of 24c, and the suction side of each compression mechanism 21a to 21c is connected to the gas side of the use side heat exchanger 32a, 32b, ... via the refrigerant gas communication pipe 5. ing. Further, the liquid side shutoff valves 25a to 25c and the gas side shutoff valves 26a to 26c are opened, and the use side expansion valves 31a, 31b,... Are adjusted so as to depressurize the refrigerant.

[0029] In the state of the refrigerant circuit 7 of the air conditioner 1, outdoor fans (not shown) of the heat source units 2a to 2c, indoor fans (not shown) of the utilization units 3a, 3b,. When the compression mechanisms 21a to 21c are started, the refrigerant gas is sucked into the compression mechanisms 21a to 21c and compressed, and then sent to the heat source side heat exchange 24a to 24c via the four-way switching valves 23a to 23c. It is condensed by exchanging heat with the outside air. This condensed refrigerant liquid is merged into the refrigerant liquid communication pipe 4 and sent to the use units 3a, 3b,. The refrigerant liquid sent to the usage units 3a, 3b,... Is decompressed by the usage side expansion valves 31a, 31b,. Evaporates through heat exchange. The evaporated refrigerant gas is sent to the heat source units 2 a to 2 c through the refrigerant gas connection pipe 5. The refrigerant gas flowing through the refrigerant gas communication pipe 5 passes through the four-way switching valves 23a to 23c of the heat source units 2a to 2c, and is again sucked into the compression mechanisms 21a to 21c. In this way, the cooling operation is performed.

[0030] (Heating operation)

Next, the heating operation will be described. During heating operation, in all the heat source units 2a to 2c, the four-way switching valves 23a to 23c are in the state indicated by the broken lines in FIG. 1, that is, the discharge side of each compression mechanism 21a to 21c is connected via the refrigerant gas communication pipe 5. Use side heat exchangers 32a, 32b, ... connected to the gas side, and the suction side of each compression mechanism 21a-21c is heat source side heat exchange It is in the state connected to the gas side of vessels 24a-24c. Further, the liquid side closing valves 25a to 25c and the gas side closing valves 26a to 26c are opened, and the heat source side expansion valves 29a to 29c are adjusted in opening degree so as to depressurize the refrigerant.

In the state of the refrigerant circuit 7 of the air conditioner 1, outdoor fans (not shown) of the heat source units 2a to 2c, indoor fans (not shown) of the use units 3a, 3b,. When 21c is activated, the refrigerant gas is sucked into the compression mechanisms 21a to 21c and compressed, and then joined to the refrigerant gas communication pipe 5 via the four-way switching valves 23a to 23c of the heat source units 2a to 2c. And sent to the usage units 3a, 3b,. Then, the refrigerant gas sent to the use units 3a, 3b,... Is condensed by exchanging heat with room air in the use side heat exchangers 32a, 32b,. The condensed refrigerant liquid joins the refrigerant liquid communication pipe 4 via the use side expansion valves 3 la, 31b,... And is sent to the heat source units 2a to 2c. The refrigerant liquid flowing through the refrigerant liquid connection pipe 4 is evaporated by exchanging heat with the outside air at the heat source side heat exchange 24a to 24c of the heat source units 2a to 2c. The evaporated refrigerant gas is again sucked into the compression mechanisms 21a to 21c via the four-way switching valves 23a to 23c of the heat source units 2a to 2c. In this way, the heating operation is performed.

[0031] <Refrigerant amount determination operation>

Next, the refrigerant quantity determination operation will be described. The refrigerant quantity judgment operation includes a refrigerant leak detection operation and a refrigerant automatic charging operation.

(Refrigerant leak detection operation)

The refrigerant leakage detection operation, which is one of the refrigerant quantity determination operations, will be described with reference to FIGS. Here, FIG. 2 is a flowchart in the refrigerant leak detection operation.

During cooling operation or heating operation in normal operation, switch to the refrigerant leakage detection operation, which is one of the refrigerant amount determination operations, periodically (for example, once every month, when load processing is not required in the air-conditioned space). An example will be described in which it is detected whether or not the refrigerant in the refrigerant circuit 7 has leaked to the outside due to unforeseen reasons.

First, in step S 1, a refrigerant quantity determination preparation operation is performed before the refrigerant leakage detection operation. This refrigerant quantity determination preparation operation will be described later.

Next, in step S2, the operation in the normal operation such as the cooling operation and the heating operation described above is performed. It is judged whether or not the force has passed for a certain period of time (for example, 1 month), and if the operation in normal operation has passed for a certain period of time, the process proceeds to the next step S2.

In step S3, when the operation in the normal operation has passed for a fixed time, the four-way switching valves 23a to 23c of the refrigerant circuit 7-power heat source units 2a to 2c are in the state shown by the solid line in FIG. 3b, the use side expansion valves 31a, 31b, ... are opened, the compression mechanisms 21a to 21c and the outdoor fan (not shown) are activated, and the use units 3a, 3b, · · · · · · · · · · Forced cooling operation.

[0033] In step S4, the condensation pressure control by the outdoor fan, the superheat degree control by the use side expansion valves 3la, 31b, ..., the evaporation pressure control by the compression mechanisms 21a to 21c are performed, and the inside of the refrigerant circuit 7 is performed. The state of the refrigerant circulating through the is stabilized.

In step S6, it is determined whether or not the value of the supercooling degree detected in step S5 is appropriate. Here, when detecting the degree of supercooling in step S5, the configuration of the use units 3a, 3b,... And the length of the refrigerant liquid communication pipe 4 and the refrigerant gas communication pipe 5 are irrelevant.

It is now possible to judge the suitability of the amount of refrigerant charged in the inside! / Speak.

[0034] If the amount of refrigerant to be additionally charged is small and the required amount of refrigerant has been reached, then the refrigerant amount in the heat source side heat exchangers 24a to 24c becomes small (specifically, This means that the supercooling value detected in step S5 is smaller than the supercooling value corresponding to the required refrigerant amount at the condensation pressure of the heat source side heat exchangers 24a to 24c. For this reason, in step S5, the detected supercooling value is substantially the same as the target supercooling value (for example, the difference between the detected supercooling value and the target supercooling value is less than a predetermined value). ), It is determined that there is no refrigerant leakage, and the refrigerant leakage detection operation is terminated.

On the other hand, when the supercooling degree value detected in step S5 is smaller than the target supercooling degree value V, the value (for example, the difference between the detected supercooling degree value and the target supercooling degree value is a predetermined value or more). If there is, it is determined that a refrigerant leak has occurred, the process proceeds to step S7, a warning is displayed to notify that a refrigerant leak has been detected, and then the refrigerant leak detection operation is performed. finish.

[0035] (Automatic refrigerant charging operation)

The automatic refrigerant charging operation, which is one of the refrigerant quantity determination operations, will be described with reference to FIGS. Here, FIG. 3 is a flowchart of the automatic refrigerant charging operation.

The heat source units 2a to 2c that are prefilled with refrigerant are connected to the usage units 3a, 3b, ... via the refrigerant liquid connection pipe 4 and the refrigerant gas connection pipe 5 at the site. An example will be described in which the refrigerant circuit 7 is additionally filled with a refrigerant that is insufficient according to the lengths of the refrigerant liquid communication pipe 4 and the refrigerant gas communication pipe 5 after the configuration of FIG.

First, the liquid side closing valves 25a to 25c and the gas side closing valves 26a to 26c of the heat source units 2a to 2c are opened, and the refrigerant circuit 7 is filled with the refrigerant preliminarily charged in the heat source units 2a to 2c.

[0036] Next, a person who performs the refrigerant charging operation uses a remote controller (not shown), or a use side control unit (not shown) or a heat source unit 2a of the use units 3a, 3b,. When the operation control devices 6a to 6c of ~ 2c are directly instructed to perform the automatic refrigerant charging operation, which is one of the refrigerant quantity determination operations, the automatic refrigerant operation is performed according to the procedure from step S11 to step S14. Filling operation is performed.

In step S11, a refrigerant quantity determination preparation operation is performed before the automatic refrigerant charging operation. This refrigerant quantity determination preparation operation will be described later.

In step S12, when an instruction to start the automatic refrigerant charging operation is issued, the refrigerant circuit 7 is in a state where the four-way switching valves 23a to 23c of the heat source units 2a to 2c are indicated by solid lines in FIG. The use side expansion valves 31a, 31b, 3a, 3b, ... are opened, the compression mechanisms 21a-21c and the outdoor fan (not shown) are activated, and the use units 3a, 3b, ... • All the items are forcibly cooled.

[0037] In step S13, the condensation pressure control by the outdoor fan, the superheat degree control by the use side expansion valves 3la, 31b, ..., and the evaporation pressure control by the compression mechanisms 21a to 21c are performed, and the inside of the refrigerant circuit 7 is performed. The state of the refrigerant circulating through the is stabilized.

In step S14,

Detect the degree of supercooling at the mouth. In step S15, the suitability of the refrigerant amount is determined from the value of the degree of supercooling detected in step S14. Specifically, when the supercooling degree value detected in step S14 is smaller than the target supercooling degree value and refrigerant charging is not completed, the supercooling degree value reaches the target supercooling degree value. In addition, the above-described processing of Step S13 and Step S14 is repeated. In this automatic refrigerant charging operation, the refrigerant circuit 7 is filled only by the refrigerant leakage or the like during the trial operation after the site construction. It can also be used for additional charging of refrigerant when the amount of refrigerant decreases.

[0038] <Refrigerant quantity determination preparation operation>

In the refrigerant amount determination operation described above, the refrigerant stagnation determination means 8a to 8c indicate that the refrigerant has stagnated in the compression mechanisms 21a to 21c when the temperature detected by the temperature sensors 6la to 61c is lower than the predetermined temperature. Judgment is made and a signal is sent to the operation control device 6a that the refrigerant has stagnated. Receiving the signal from the refrigerant stagnation judging means 8a to 8c, the operation control device 6a performs control to perform preliminary operation (refrigerant stagnation elimination operation) so that the compressors 22a to 22c, 27a to 27c, and 28a to 28c are sufficiently warmed. is doing.

In FIG. 4, in step S21, the operation control device 6a determines whether or not the temperatures in the compression mechanisms 21a to 21c measured by the temperature sensors 61a to 61c are lower than a predetermined temperature, and the compressor temperature is If the temperature is lower than the predetermined temperature, the process proceeds to step S22, and if not, the process proceeds to step S23. In step S22, the refrigerant stagnation elimination operation is performed, and the process proceeds to step S23. In step 23, an oil return operation is performed, and when the oil return operation is completed, the process proceeds to step S2 when the refrigerant amount determination operation is the refrigerant leak detection operation, and when the refrigerant amount determination operation is the automatic refrigerant charging operation, the process proceeds to step S2. Move to S12.

[0039] (Refrigerant stagnation operation)

Here, the refrigerant stagnation elimination operation in step S22 will be described. When receiving a signal from the refrigerant stagnation determining means 8a to 8c, the operation control device 6a issues a command to drive all the compression mechanisms 21a to 21c of the heat source units 2a to 2c. However, for the heat source units 2b and 2c, the slave unit operation control devices 6b and 6c receive the command from the master unit operation control device 6a, and the slave unit operation control devices 6b and 6c apply to the compression mechanisms 21b and 21c. Drive The command is issued.

In FIG. 5, in step S31, the compressors 22a to 22c are driven, and the process proceeds to step S32. In step S32, the compressors 22a to 22c are stopped 15 minutes after step S31, the compressors 27a to 27c are driven, and the process proceeds to step S33. In step S33, the compressors 27a to 27c are stopped 15 minutes after step S32, the compressors 28a to 28c are driven, and the process proceeds to step S34. In step S34, step S33 force also stops the compressors 28a to 28c after 15 minutes and ends the refrigerant stagnation elimination operation.

[0040] (Oil return operation)

When the refrigerant stagnation elimination operation is completed, or when the compressor temperature is higher than the predetermined temperature in step S21, the oil return operation in step S23 is performed. Here, the oil return operation will be described with reference to FIG.

In step S41, the operation control device 6a issues a command to drive one of the compressors of the heat source units 2a to 2c (here, the compressors 22a to 22c). However, for the heat source units 2b and 2c, the operation control devices 6b and 6c of the slave units receive commands from the operation control device 6a of the master unit, and the operation control devices 6b and 6c of the slave units are connected to the compressors 22b and 22c. Give a command to drive. When step S41 ends, the process proceeds to step S42. In step S42, the operation control device 6a issues a command to stop after driving the compressors 22a to 22c for 5 minutes. Thereby, the oil accumulated in the refrigerant circuit 7 can be returned to the compression mechanisms 21a to 21c.

[0041] <Features>

(1)

In the air conditioner 1, when the refrigerant amount determination operation is performed, the refrigerant stagnation in the refrigerating machine oil inside the compressors 22a to 22c, 27a to 27c, and 28a to 28c in advance by the refrigerant stagnation determination means. A determination is made whether or not. When the refrigerant stagnation determining means determines that the refrigerant is stagnation in the refrigerating machine oil in the compression mechanisms 21a to 21c, the operation control device 6a performs the refrigerant stagnation elimination operation. Therefore, in the air conditioner 1, it is possible to perform the force determination operation by eliminating the refrigerant accumulation in the refrigerating machine oil in the compression mechanisms 21a to 21c. For this reason, during the refrigerant quantity determination operation, the refrigerators in the compression mechanisms 21a to 21c The amount of refrigerant that dissolves in oil can be reduced, and the prediction error of the amount of refrigerant can be reduced. For this reason, during the refrigerant quantity determination operation, the refrigerant can be prevented from stagnation in the refrigerating machine oil in the compression mechanisms 21a to 21c, so that a highly accurate refrigerant quantity determination operation can be performed.

[0042] (2)

In the air conditioner 1, the determination of the refrigerant stagnation determination means is performed based on the temperature in the compression mechanisms 21a to 21c. Therefore, it is possible to measure the temperature inside the compressors 22a to 22c, 27a to 27c, 28a to 28c, and to determine whether or not the refrigerant has stagnated in the refrigeration machine oil in the compression mechanisms 21a to 21c. Become.

(3)

In the air conditioner 1, in the refrigerant stagnation elimination operation, the compressors 22a to 22c, 27a to 27c, and 28a to 28c are warmed up for a first predetermined time. Therefore, the refrigerant stagnation canceling operation can warm the compressor mechanisms 21a to 21c by operating the compressors 22a to 22c, 27a to 27c, and 28a to 28c for the first predetermined time (warm-up operation). . For this reason, the inside of the compression mechanisms 2la to 21c can be sufficiently warmed, and the stagnation of the refrigerant with respect to the refrigerating machine oil in the compression mechanisms 21a to 21c can be eliminated.

[0043] (4)

In the air conditioner 1, there are a plurality of heat source units 2a to 2c. Therefore, by rotating the heat source units 2a to 2c in the system for a certain period of time, even if the load is low, the load is not biased to one unit and the life of the entire system can be extended.

(Five)

In this air conditioner 1, the compression mechanisms 21a to 21c have a plurality of compressors 22a to 22c, 27a to 27c, 28 & to 28c! Therefore, it is possible to change the capacity of the compression mechanisms 21a to 21c by controlling the number of compressors 22 & ~ 22c, 27 & ~ 27c, 28a ~ 28c, so that the usage units 3a, 3b, ... Even when the operation load is reduced, it becomes possible to continue the operation of all the heat source units 2a to 2c, and the accumulation of oil in the refrigerant circuit 7 can be prevented as much as possible. Even if one of the compressors 22a-22c, 27a-27c, 28a-28c breaks down, the remaining compressors can handle them. For this reason, it is possible to avoid a complete stop of the air conditioning. [0044] (6)

In this air conditioner 1, when there are a plurality of compressors 22a to 22c, 27a to 27c, and 28a to 28c, all the compressors 22a to 22c, 27a to 27c, and 28a to 28c are replaced one by one. Let it run for a predetermined time. Because the cooling operation is performed at a low outside temperature during the refrigerant stagnation elimination operation, it is difficult to operate all the compressors 22a to 22c, 27a to 27c, and 28a to 28c due to low load. For this reason, it is possible to drive all of the compressors 22a to 22c, 27a to 27c, and 28a to 28c in advance by operating them one by one for the second predetermined time.

(7)

In the air conditioner 1, the oil return operation is further performed after the refrigerant stagnation elimination operation. Further, in this oil return operation, control is performed so that the refrigerant flow rate in the pipe becomes equal to or higher than a predetermined flow rate. Therefore, the oil accumulated in the refrigerant circuit 7 can be returned by further performing the oil return operation. In addition, it is possible to reliably return the oil accumulated in the refrigerant circuit 7 to the compressor 22a to 22c, 27a to 27c, 28a to 28c. For this reason, it becomes possible to operate the refrigerant quantity determination operation with higher accuracy.

[0045] <Other embodiments>

As mentioned above, although embodiment of this invention was described based on drawing, specific structure can be changed in the range which does not deviate from the summary of this invention which is not restricted to these embodiment.

(A)

In the above-described embodiment, the air-cooled heat source units 2a to 2c that use air-cooled heat source units 2a to 2c using outside air as the heat source are used. Also good.

(B)

In the above embodiment, the air conditioner 1 is capable of switching between cooling and heating, but an air conditioner dedicated to cooling may be an air conditioner capable of simultaneous cooling and heating.

[0046] (C)

In the above embodiment, three heat source units 2a to 2c having the same air conditioning capability are connected in parallel, but heat source units having different air conditioning capabilities may be connected in parallel. Two or more heat source units may be connected in parallel.

(D)

In the above-described embodiment, the operation control devices 6a to 6c may have one operation control device as a whole of the force and air conditioner built in each of the heat source units 2a to 2c.

(E)

In the above embodiment, the refrigerant stagnation determining means cuts the refrigerant power in the compressor 22a-22c, 27a-27c, 28a-28c inner casing based on the outside air temperature. It may be determined based on the temperature in the force compression mechanism 21a to 21c, or it may be determined based on the weather information obtained from the weather information providing external server 10 using the communication line 9 such as the Internet. Alternatively, it may be determined based on the refrigerant stagnation period in which the predicted refrigerant is likely to stagnate inside the compressors 22a to 22c, 27a to 27c, and 28a to 28c.

[0047] (F)

In the embodiment, the heat source units 2a to 2c are not limited to a plurality of power units, but may be a single unit.

(G)

In the above embodiment, during the refrigerant stagnation elimination operation, the three compressors 22a to 22c, 27a to 27c, and 28a to 28c are not limited to the force of 15 minutes by fifteen minutes f¾. It may be 20, 30 minutes. Further, it is not necessary to drive all of the compressors 22a to 22c, 27a to 27c, and 28a to 28c, as long as it is an operation that drives at least the compressor that is not driven in the refrigerant amount determination operation.

(H)

In the embodiment, the refrigerant stagnation elimination operation is not limited to the force performed by the warm-up operation that drives the compressors 22a to 22c, 27a to 27c, and 28a to 28c to warm the compression mechanisms 21a to 21c. You may carry out by heating 21a-21c with a heater.

[0048] (I)

In the embodiment, the oil return operation is performed immediately after the refrigerant stagnation elimination operation. It is not always necessary to perform the oil return operation.

Industrial applicability

The air conditioner according to the present invention can eliminate the stagnation of the refrigerant with respect to the refrigerating machine oil in the compression mechanism before the refrigerant amount determination operation, and enables a highly accurate refrigerant amount determination operation. This is useful as a refrigerant circuit and an air conditioner equipped with the refrigerant circuit.

Claims

The scope of the claims

[1] A heat source unit (2a to 2c) having a compression mechanism (21a to 21c) and a heat source side heat exchange (24a to 24c), a refrigerant communication pipe (4, 5) to which the heat source unit is connected, Use units (3a, 3b) that have expansion mechanisms (29a to 29c, 31a, 31b, ...) and use-side heat exchange (32 &, 32b, ...) and are connected to the refrigerant communication pipe A refrigerant circuit (7) comprising:

Refrigerant stagnation judging means (8a-8c) capable of judging whether or not the refrigerant is stagnation in the compression mechanism;

When performing the refrigerant amount determination operation for determining the refrigerant amount in the refrigerant circuit, if the refrigerant stagnation determining means determines in advance that the refrigerant is stagnation in the compression mechanism, the refrigerant stagnation An operation control device (6a to 6c) for performing refrigerant stagnation elimination operation to eliminate

Air conditioner (1) with

[2] The refrigerant stagnation determining means (8a to 8c) makes a determination based on the temperature in the compression mechanism (21a to 21c).

The air conditioner (1) according to claim 1.

[3] The refrigerant stagnation determining means (8a to 8c) makes a determination based on the outside air temperature.

The air conditioner (1) according to claim 1.

[4] The refrigerant stagnation determination means (8a to 8c) is connected to a network (9), acquires weather information via the network, and makes a determination based on the weather information. The air conditioner (1) described.

[5] The refrigerant stagnation determining means (8a to 8c) makes a determination based on a refrigerant stagnation period in which the refrigerant is predicted to easily stagnate in the compression mechanism (21a to 21c).

The air conditioner (1) according to claim 1.

[6] The operation control devices (6a to 6c) perform the refrigerant stagnation elimination operation as the compression mechanism (

21a-21c) is driven for the first predetermined time,

The air conditioner (1) according to any one of claims 1 to 5.

[7] There are a plurality of the heat source units (2a to 2c).

The air conditioner (1) according to any one of claims 1 to 6.

[8] The compression mechanism (21a-21c) has a plurality of compressors (22a-22c, 27a-27c, 28a-28c),

The air conditioner (1) according to any one of claims 1 to 7.

[9] The refrigerant stagnation elimination operation is an operation that does not drive at the time of the refrigerant quantity determination operation, and drives the compressor at least.

The air conditioner (1) according to claim 8.

[10] In the refrigerant stagnation elimination operation, the operation control device (6a to 6c)

22a-22c, 27a-27c, 28a-28c) are performed one by one at intervals of the second predetermined time,

The air conditioner (1) according to claim 8.

[11] A heater for heating the compression mechanism (21a to 21c) is further provided,

The air conditioner (1) according to claim 1, wherein the refrigerant stagnation elimination operation is an operation of heating the compression mechanism with the heater.

[12] The operation control devices (6a to 6c) further perform an oil return operation immediately after the refrigerant stagnation elimination operation,

The air conditioner (1) according to any one of claims 1 to 11.

[13] The oil return operation is an operation of controlling the refrigerant flow rate in the pipe of the refrigerant flowing through the refrigerant circuit (7) to be equal to or higher than a predetermined flow rate.

The air conditioner (1) according to claim 12.