ES2636912T3 - Air conditioner - Google Patents

Abstract

An air conditioner (1) comprising: a refrigerant circuit (7) having a heat source unit (2a to 2c) having a compression mechanism (21a to 21c) and a heat exchanger on the side of the heat source (24a to 24c), a refrigerant communication pipe (4, 5) to which the heat source unit (2a to 2c) is connected, an expansion mechanism (29a to 29c, 31a, 31b, ...), and a utilization unit (3a, 3b, ...) that has a heat exchanger on the utilization side (32a, 32b, ...) and that is connected to the refrigerant communication pipe ( 4, 5), means for determining refrigerant stagnation (8a to 8c) configured to determine if a refrigerant is stagnant in an oil of the refrigeration machine within the compression mechanism (21a to 21c); and an operation controller (6a to 6c), characterized in that said controller is configured to carry out a refrigerant clearing operation to eliminate the refrigerant stagnation in the oil of the refrigeration machine in the event that the means of Determination of refrigerant stagnation (8a to 8c) has determined in advance that the refrigerant is stagnant in the refrigeration machine oil inside the compression mechanism (21a to 21c) before a quantity determination operation is carried out of refrigerant to determine an amount of refrigerant in the refrigerant circuit.

Description

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DESCRIPTION

AIR CONDITIONER Field of the invention

The present invention relates to a refrigerant circuit of an air conditioner and an air conditioner provided therewith.

Background of the invention

An example of a conventional refrigerant leak detector in a refrigeration apparatus is described in Patent Document 1. In this refrigerant leak detector, a condensing refrigerant temperature and an evaporating refrigerant temperature are maintained at a value fixed using condensation refrigerant temperature adjustment means and evaporation refrigerant temperature adjustment means, and a refrigerant leak detection operation is performed to detect refrigerant leaks in a refrigeration cycle using calculation means of temperature difference to compare output signals of a refrigerant discharge temperature detector and set values and calculate a temperature difference. Therefore, the temperature of the condensation refrigerant that flows through a condenser and the temperature of the evaporation refrigerant that flows through an evaporator are maintained at a fixed value, so that the refrigerant temperature is adjusted to the set value Discharge coolant discharge temperature according to an adequate amount of coolant. The set value and the output signal of the discharge refrigerant temperature detector are compared, and it is determined that a refrigerant leak has not occurred when the value is less than the set value, and it is determined that a leak has occurred of refrigerant when the value is greater than the set value.

Furthermore, in Patent Document 2, which forms the basis for the preamble of claim 1, it describes means for protecting a compressor in an air conditioning system by detecting two levels of liquid in the compressor oil pan for Determine if there is enough oil and an excess of refrigerant before starting the compressor.

Patent Document 1

Japanese Patent Application Publication No. H11-211292

Patent Document 2

US 2004/194485 A1

Description of the invention

Problems solved by the invention

However, with the technique of Patent Document 1, there is a risk because the predicted error in the amount of refrigerant will increase because the amount of refrigerant that dissolves in the oil of the refrigeration machine within the compression mechanism It grows when the outside temperature is low. The refrigerant leak detection error increases when the internal oil temperature is low immediately after the compressor has started and when only one portion of the compressors is operated during a refrigerant leak detection operation when there are a plurality of compressors .

An objective of the present invention is to resolve the refrigerant stagnation in the refrigeration machine oil inside a compressor, to minimize the prediction error in the amount of refrigerant produced by the difference in refrigerant solubility in the oil.

Means to solve the problems

The air conditioner according to a first aspect is provided with a refrigerant circuit, a means of determining refrigerant stagnation, and an operating controller. The refrigerant circuit is a circuit that includes a heat source unit, refrigerant communication pipes, expansion mechanisms, and a utilization unit. The heat source unit has a compression mechanism and a heat exchanger on the heat source side. A heat source unit is connected to the refrigerant communication pipes. The use unit has a heat source exchanger on the use side and is connected to the refrigerant communication tubing. The means for determining refrigerant stagnation can determine if the refrigerant is stagnant within the compression mechanism. The controller operation controller performs a coolant unclogging operation to eliminate the coolant stagnation in case the coolant is stagnant inside the compression mechanism when it is carried out

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a refrigerant quantity determination operation to determine the amount of refrigerant within the refrigerant circuit.

In the air conditioner, the means for determining refrigerant stagnation determine in advance whether the refrigerant is stagnant in the oil of the refrigeration machine within the compression mechanism when the refrigerant quantity determination operation is carried out. The operation controller performs the operation of refrigerant de-stagnation when the means of determining the refrigerant stagnation determine that the refrigerant is stagnant in the oil of the refrigeration machine within the compression mechanism.

Therefore, in the air conditioner, the operation of determining the amount of refrigerant can be carried out after having eliminated the refrigerant stagnation in the oil of the refrigeration machine within the compression mechanism. For this reason, the amount of refrigerant that dissolves in the oil of the refrigeration machine within the compression mechanism can be greatly reduced and the error in predicting the amount of refrigerant can be reduced during the operation of determining the amount of refrigerant. A more precise refrigerant quantity determination operation is possible because the refrigerant stagnation in the refrigeration machine oil in the compression mechanism can be eliminated during the refrigerant quantity determination operation.

The air conditioner according to a second aspect is the air conditioner according to the first aspect, in which the means for determining refrigerant stagnation make a determination based on the temperature within the compression mechanism.

In the air conditioner, the determination of the means for determining refrigerant stagnation is carried out based on the temperature within the compression mechanism. The refrigerant leaks more easily in the oil of the refrigeration machine when the temperature inside the compression mechanism is low. Therefore, it is possible to determine that the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism when the temperature within the compression mechanism is low. For this reason, it is possible to determine whether the refrigerant is stagnant in the oil of the refrigeration machine within the compression mechanism based on the temperature within the compression mechanism.

The air conditioner according to a third aspect is the air conditioner according to the first aspect, in which the means for determining refrigerant stagnation make a determination based on the temperature of the outside air.

In the air conditioner, the means for determining refrigerant stagnation carry out the determination based on the outside air temperature. The refrigerant easily stalls in the oil of the refrigeration machine when the temperature inside the compression mechanism is low. Therefore, the temperature inside the compression mechanism can be predicted because the outside air temperature can be measured. For this reason, the determination that the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism is made possible when it is predicted that the temperature within the compression mechanism is low. The determination of whether the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism is thus made possible.

The air conditioner according to a fourth aspect is the air conditioner according to the first aspect, in which the means for determining refrigerant stagnation make a determination based on information about the weather.

In the air conditioner, the refrigerant stagnation determination means make a determination based on information about the atmospheric time obtained through a network connected to the refrigerant stagnation determination means. Therefore, the outside temperature can be acquired through the weather information and the temperature within the compression mechanism can be predicted. Accordingly, it is possible to determine that the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism when it is predicted that the temperature within the compression mechanism is low. The determination of whether the refrigerant is stagnant in the oil of the refrigeration machine within the compression mechanism is thus made possible.

The conditioner according to a fifth aspect is the conditioner according to the first aspect, in which the refrigerant stagnation determination means make a determination based on a refrigerant stagnation interval in which the refrigerant is predicted to stagnate easily within the compression mechanism.

In the air conditioner, the refrigerant stagnation determination means carry out a determination based on a time interval that has been established in advance. The refrigerant easily stalls in the oil of the refrigeration machine when the temperature inside the compression mechanism is low. The determination is carried out by establishing a time interval in which the temperature is predicted

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Inside the compression mechanism is low. Therefore, the user sets the time interval in which the temperature within the compression mechanism is predicted to be low, so that the refrigerant stagnation can be predicted without measuring the temperature within the compression mechanism. In this way it is possible to determine if the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism. Also, production costs can be reduced because it is no longer necessary to install a temperature sensor or the like.

The air conditioner according to a sixth aspect is the air conditioner according to any of the first to fifth aspects, in which the operation controller carries out a control to operate the compression mechanism for a first prescribed time as a refrigerant de-stagnation operation. In the air conditioner, the refrigerant de-stagnation operation is a heating operation that is carried out by operating a compressor for a first predetermined time interval. Therefore, in the refrigerant de-stagnation operation, a compressor is operated for a first predetermined time interval, so that the interior of the compression mechanism can be heated. For this reason, the refrigerant stagnation in the refrigeration machine oil within the compression mechanism can be eliminated.

The air conditioner according to a septic aspect is the air conditioner according to any of the first to sixth aspects, in which a plurality of the heat source units is present.

In the air conditioner, a plurality of heat source units is present. Therefore, the lifetime of the entire system can be extended without charging only a single unit even during low-load operation, because the heating source units in the system can be arranged according to a rotation and operated according to time intervals fixed a unit at every moment.

The air conditioner according to an eighth aspect is the air conditioner according to any of the first to seventh aspects, in which the compression mechanism has a plurality of compressors. In the air conditioner, the compression mechanism has a plurality of compressors. Therefore, all heat source units can be operated continuously and the accumulation of refrigerant and oil in the refrigerant circuit can be avoided as much as possible even when the operating load of the utilization unit has been reduced because the capacity of the compression mechanism can be modified by controlling the number of compressors. The remaining compressors can handle the load even if one of the compressors fails. For this reason, complete shutdown of the air conditioner can be avoided.

The air conditioner according to a ninth aspect is the air conditioner according to the eighth aspect, in which the coolant uncoupling operation is an operation to drive at least one compressor that is not operated during the operation of determining amount of refrigerant

In the air conditioner, in relation to the compressors that are used during the pre-operation, at least one compressor that is not activated when the refrigerant quantity determination is being carried out is activated because the compressors that are operated to determine The amount of refrigerant can be sufficiently heated at the time of the operation of determining the amount of refrigerant when there are a plurality of compressors.

Therefore, the energy used can be reduced because it is not necessary to operate all the compressors. In addition, the time required for the operation of refrigerant de-stagnation can be reduced.

The air conditioner according to a tenth aspect is the air conditioner according to the eighth aspect, in which the coolant unclogging operation is an operation in which the operation controller operates all the compressors one by one in a manner sequential for a second predetermined time interval.

In the air conditioner, all compressors are operated for a second predetermined period of time in a single-unit rotation when there is a plurality of compressors. It is difficult to make all the compressors operate at the same time at the time of the refrigerant de-stagnation operation due to low load because the refrigeration operation is carried out when the outside temperature is low. For this reason, the units are operated one by one for a second predetermined time interval, so that all compressors can be operated in advance.

The air conditioner according to a tenth aspect is the air conditioner according to the first aspect, which also comprises a heater for heating the compression mechanism. The refrigerant de-stagnation operation is an operation to heat the compression mechanism using the heater.

In the air conditioner, the refrigerant de-stagnation operation can be carried out by heating the compression mechanism using a heater. Therefore, the refrigerant stagnation can be eliminated without operating a compressor. For this reason, the operating time of a compressor can be reduced and can

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extend the life of a compressor because it is not necessary to operate the compressor during the operation of refrigerant de-stagnation.

The air conditioner according to a twelfth aspect is the air conditioner according to any of the first to the tenth aspects, in which the operation controller also performs an oil return operation immediately after the stagnation operation. of refrigerant The oil return operation is an operation to return the accumulated oil in the refrigerant circuit to the compression mechanism.

In the air conditioner, an oil return operation is also carried out after the refrigerant de-stagnation operation. Therefore, the oil that is accumulated in the refrigerant circuit can be returned to the compression mechanism by also carrying out an oil return operation. The operation of determining the amount of refrigerant can therefore be carried out with greater precision.

The air conditioner according to a thirteenth aspect is the air conditioner according to the twelfth aspect, where the oil return operation is an operation to control the refrigerant flowing through the refrigerant circuit so that the refrigerant flows for tubenas at or above a predetermined rate.

In the air conditioner, the oil return operation is an operation to control the refrigerant so that the refrigerant flows into the pipes at a predetermined or higher rate. Therefore, the oil accumulated in the refrigerant circuit can be reliably returned to the compression mechanism. The operation of determining the amount of refrigerant can therefore be carried out with greater precision.

Effect of the invention

In the air conditioner according to the first aspect, the operation of determining the amount of refrigerant can be carried out after the stagnation of the refrigerant in the oil of the refrigeration machine within the compression mechanism has been removed. The amount of refrigerant that has dissolved in the oil of the refrigeration machine within the compression mechanism can accordingly be reduced as much as possible at the time of the operation of determining the amount of refrigerant, and the prediction error can be reduced by The amount of refrigerant. A more precise refrigerant quantity determination operation is possible because the refrigerant stagnation can be eliminated in the oil of the refrigeration machine in the compression mechanism during the refrigerant quantity determination operation.

In the air conditioner according to the second aspect, it can be determined that the refrigerant is stuck in the refrigeration machine oil inside the compression mechanism when the temperature inside the compression mechanism is low. For this reason, the decision about whether the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism can be made based on the temperature within the compression mechanism.

In the air conditioner according to the third aspect, the temperature within the compression mechanism can be predicted because the outside air temperature can be measured. Accordingly, it can be determined that the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism when it can be predicted that the temperature within the compression mechanism is low. In this way it can be determined whether the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism.

In the air conditioner according to the fourth aspect, the outside air temperature can be acquired from weather information and the temperature within the compression mechanism can be predicted. Accordingly, it can be determined that the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism when it can be predicted that the temperature within the compression mechanism is low. In this way, it can be determined whether the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism.

In the air conditioner according to the fifth aspect, a user sets a time interval in which it is predicted that the temperature within the compression mechanism is low, so that the refrigerant stagnation can be predicted without measuring the temperature within the compression mechanism Therefore, it is possible to determine whether the refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanism. Production costs can be reduced because it is no longer necessary to install a temperature sensor or similar.

In the air conditioner according to the sixth aspect, the interior of the compression mechanism can be heated by operating a compressor for a first predetermined time interval. For this reason, the refrigerant stagnation in the refrigeration machine oil within the compression mechanism can be eliminated.

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In the air conditioner according to the seventh aspect, the life of the entire system can be extended without setting the load exclusively on a single unit even during low load operations because the heat source units in the system can be placed in rotation and actuated according to fixed time intervals one unit at a time.

In the air conditioner according to the eighth aspect, all heat source units can be operated continuously and the accumulation of refrigerant and oil in the refrigerant circuit can be avoided as much as possible even when the operating load of the units of use is low, because the capacity of the compression mechanism can be modified by controlling the number of compressors. The rest of the compressors can handle the load even if one of the compressors fails. For this reason, a complete stop of the air conditioner can be avoided.

In the air conditioner according to the ninth aspect, the energy used can be reduced because all compressors are not required to operate. In addition, the time required for the operation of refrigerant clearing can be reduced.

In the air conditioner according to the tenth aspect, all compressors can be operated in advance by operating the compressors for a second predetermined time interval one unit at a time.

In the air conditioner according to the tenth aspect, the refrigerant stagnation can be eliminated without operating a compressor. The operating time of a compressor can be reduced and the life of the compressors can be extended because it is not necessary to operate a compressor during the operation of refrigerant de-stagnation.

In the air conditioner according to the twelfth aspect, the oil that has accumulated in the refrigerant circuit can be returned to the compression mechanism by performing an oil return operation. The operation of determining the amount of refrigerant can therefore be carried out with greater precision.

In the air conditioner according to the thirteenth aspect, the oil that has accumulated within the refrigerant circuit can be reliably returned to the compression mechanism. The operation of determining the amount of refrigerant can therefore be carried out with greater precision.

Brief description of the drawings

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

FIG. 2 is a flow chart showing the flow of a refrigerant leak detection operation related to an embodiment of the present invention.

FIG. 3 is a flow chart showing the flow of an automatic refrigerant charging operation related to an embodiment of the present invention.

FIG. 4 is a flow chart showing the flow of a refrigerant quantity determination operation related to an embodiment of the present invention.

FIG. 5 is a flow chart showing the flow of a refrigerant de-staining operation related to an embodiment of the present invention.

FIG. 6 is a flow chart showing the flow of an oil return operation related to an embodiment of the present invention.

FIG. 7 is a schematic diagram of an information acquisition network about the weather of an air conditioner related to a modified example (E) of an embodiment of the present invention.

Description of the reference symbols

1 air conditioner

2a to 2c Heat source units

3a, 3b ... Units of use

4, 5 Refrigerant communication pipes

6a to 6c Operation Controllers

8a to 8c Means of determination of refrigerant stagnation 21a to 21c Compression mechanisms

22a to 22c, 27a to 27c, 28a to 28c Compressors

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24a to 24c 29a to 29c 31a, 31b, 32a, 32c,.

Heat exchangers on the side of the heat source Expansion valves on the side of the heat source Expansion valves on the use side Heat exchangers on the use side

Best way to carry out the invention

(1) Air conditioner configuration

FIG. 1 shows a schematic diagram of a refrigerant circuit of an air conditioner 1 related to a first embodiment of the present invention. The air conditioner 1 is used to condition the air of a building or the like, and has a configuration in which a plurality (three in the present embodiment) of air-cooled heat source units 2a to 2c and numerous units of use 3a, 3b, ... are connected in parallel to a liquid refrigerant communication pipe 4 and a gas refrigerant communication pipe 5, respectively. In this case, only two utilization units 3a and 3b are shown. The plurality of heat source units 2a to 2c are provided with compression mechanisms 21a to 21c each of which has individual compressors of varying capacity 22a to 22c and a plurality (two in the present embodiment) of capacity compressors fixed 27a to 27c, and 28a to 28c.

The utilization units 3a, 3b, ... are mainly composed of expansion valves on the utilization side 31a, 31b, ..., heat exchangers on the utilization side 32a, 32b, ..., and pipes connected to the same, respectively. In the present embodiment, the expansion valves of the use side 31a, 31b, ... are electrically operated expansion valves connected to the side of the liquid refrigerant communication pipe 4 (referred to hereinafter as the liquid side) of heat exchangers on the use side 32a, 32b, ... to adjust the refrigerant pressure, adjust the refrigerant flow rate, and carry out other operations. In the present embodiment, the heat exchangers on the use side 32a, 32b, ... are tube heat exchangers and cross fins and are devices for exchanging heat with the indoor air. In the present embodiment, the utilization units 3a, 3b, ... are provided with an indoor fan (not shown) to take indoor air into the units and discharge air, and heat can be exchanged between the indoor air and the refrigerant flowing through the heat exchangers on the use side 32a, 32b, ...

The heat source units 2a to 2c are mainly composed of compression mechanisms 21a to 21c, four-way communication valves 23a to 23c, heat exchangers on the side of the heat source 24a to 24c, stop valves on the side of the liquid 25a to 25c, stop valves on the gas side 26a to 26c, expansion valves on the side of the heat source 29a to 29c, and tubenas connected thereto, respectively. In the present embodiment, the expansion valves on the side of the heat source 29a to 29c are electrically operated expansion valves connected to a liquid refrigerant communication pipe side 4 (hereinafter referred to as a liquid side) of the expansion valves on the side of the heat source 29a to 29c to adjust the refrigerant pressure, adjust the refrigerant flow rate, and carry out other operations. Compression mechanisms 21a to 21c have variable capacity compressors 22a to 22c, two fixed capacity compressors 27a to 27c and 28a to 28c, and an oil separator (not shown).

The compressors 22a to 22c, 27a to 27c, and 28a to 28c are devices for compressing refrigerant gas that has been absorbed and, in the present embodiment, are composed of an individual compressor of varying capacity whose operating capacity can be modified by means of the inverter control, and two fixed capacity compressors.

The four-way switching valves 23a to 23c are valves for switching the direction of the refrigerant flow when a switching is made between cooling and heating operations; during the cooling operation, the compression mechanisms 21a to 21c and the side of the gaseous refrigerant communication pipe 5 (hereinafter referred to as the gas side) of the heat exchangers on the side of the heat source 24a to 24c can be connected , and connect a suction side of the compressors 21a to 21c and the gaseous refrigerant communication tubing 5 (see the solid lines of the four-way switching valves 23a to 23c of FIG. 1); and, during the heating operation, they can connect the outputs of the compression mechanisms 21a to 21c and the gaseous refrigerant communication tubing 5, and connect the suction side of the compression mechanisms 21a to 21c and the gas side of the heat exchangers on the side of the heat source 24a to 24c (see the broken lines of the four-way switching valves 23a to 23c of FIG. 1).

In the present embodiment, the heat exchangers on the side of the heat source 24a to 24c are tube heat exchangers and cross fins and are devices for exchanging heat between the refrigerant and the outside air as a heat source. In the present embodiment, the heat source units 2a to 2c are provided with an outside fan (not shown) to take outside air into the units and discharge air, and can exchange heat between the outside air and the refrigerant flowing through heat exchangers on the side of the heat source 24a to 24c.

The stop valves of the liquid side 25a to 25c and the stop valves of the gas side 26a to 26c of the heat source units 2a to 2c are connected in parallel to the liquid refrigerant communication tubing 4

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and the gaseous refrigerant communication pipe 5. The refrigerant communication pipe Kqido 4 is connected between the liquid side of the heat exchangers on the use side 32a, 32b, ... of the use units 3a, 3b, ... and the liquid side of the heat exchangers on the side of the heat source 24a to 24c of the heat source units 2a to 2c. The gaseous refrigerant communication pipe 5 is connected between the gas side of the heat exchangers of the use side 32a, 32b,. of the utilization units 3a, 3b,. and the valves 23a, at 23c of four-way switching of the heat source units 2a to 2c.

The air conditioner 1 is also provided with means for determining refrigerant stagnation 8a to 8c and operating controllers 6a to 6c. The means for determining coolant stagnation 8a to 8c determine if coolant has stagnated within the compression mechanisms 21a to 21c. Operation controllers 6a to 6c carry out in advance a coolant unclogging operation to solve the coolant stagnation when coolant has stalled in the compression mechanisms 21a to 21c when a coolant quantity determination operation is carried out for determining the amount of refrigerant within the refrigerant circuit 7. In the present embodiment, the means for determining refrigerant stagnation and the operating controllers 6a to 6c are housed in heat source units 2a to 2c. An operation control as described above can be carried out using only the operation controller (6a in this case) of the heat source unit (2a in this case) established as the parent device. The operating controllers (6b and 6c in this case) of the heat source units (2a and 2b in this case) established as other subordinate devices can send the operating status of the compression mechanism and other detection devices and data in the various sensors to the parent operation controller 6a, and can function to send operation and stop commands to the compression mechanism and other devices through commands from the parent operation controller 6a. In this case, temperature sensors 61a to 61c are arranged, the outside air temperature is measured by means of the temperature sensors, and the temperature data is sent to the parent operation controller 6a. In operation controller 6a, a determination is made as to whether to carry out the operation of refrigerant de-stagnation.

(2) Air conditioner operation

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

<Normal operation>

(Refrigeration operation)

The refrigeration operation will be described first. During the cooling operation, the four four-way switching valves 23a to 23c of all heat source units 2a to 2c are in the state indicated by the continuous lines in FIG. 1, that is, the discharge side of the compression mechanisms 21a to 21c is connected to the gas side of the heat exchangers on the side of the heat source 24a to 24c, and the suction side of the compression mechanisms 21a 21c is connected to the gas side of the heat exchangers on the use side 32a, 32b,. through the gaseous refrigerant communication tubing 5. In addition, the liquid side stop valves 25a to 25c and the valves The gas side stop 26a to 26c opens and the opening position of the expansion valves on the use side 31a, 31b, ... is adjusted to reduce the refrigerant pressure.

In this state of the refrigerant circuit 7 of the air conditioner 1, the refrigerant gas is admitted into the compression mechanisms 21a to 21c and compressed when the outdoor fans (not shown) of the heat source units 2a to 2c and the indoor fans (not shown) and compression mechanisms 21a to 21c of the use units 3a, 3b, ... are started, so that the refrigerant gas is sent to the heat exchangers on the side of the heat source 24a to 24c through the four-way switching valves 23a to 23c, exchange heat with the outside air, and condense. The condensed refrigerant liquid is connected with the liquid refrigerant communication pipe 4 and is sent to the utilization units 3a, 3b, ... The pressure of the refrigerant fluid sent to the utilization units 3a, 3b, ... is reduced by means of the expansion valves of the use side 31a, 31b, ..., and then it is subjected to a heat exchange with indoor air in the heat exchangers of the use side 32a, 32b, ..., and then it is caused its evaporation The evaporated refrigerant gas is sent through the gaseous refrigerant communication tubing 5 next to the heat source units 2a to 2c. The refrigerant gas flowing through the gaseous refrigerant communication tubing 5 passes through the valves of

four-way switching 23a to 23c of the heat source units 2a to 2c, and then admitted in the

compression mechanisms 21a to 21c again. The cooling operation is carried out in this way.

(Heating operation)

Next, the heating operation will be described. During the heating operation, the valves of

four-way switching 23a to 23c of all heat source units 2a to 2c in the state indicated by the

dashed lines in FIG. 1, that is, the discharge side of the compression mechanisms 21a to 21c is connected to the gas side of the heat exchangers of the use side 32a, 32b, ... through the gaseous refrigerant communication pipe 5 and the suction side of the compression mechanisms 21a to 21c is connected to the

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gas side of the heat exchangers on the side of the heat source 24a to 24c. In addition, the stop valves on the liquid side 25a to 25c and the stop valves on the gas side 26a to 26c open and the opening position of the expansion valves on the side of the heat source 29a to 29c is adjusted to reduce coolant pressure.

In this state of the refrigerant circuit 7 of the air conditioner 1, the refrigerant gas is admitted into the compression mechanisms 21a to 21c and compressed when the external fans (not shown) of the heat source units 2a to 2c and the fans interiors (not shown) and the compression mechanisms 21a to 21c of the utilization units 3a, 3b, ... are started, so that the refrigerant gas is connected with the gaseous refrigerant communication tubing 5 through the valves of four-way switching 23a to 23c of the heat source units 2a to 2c and is sent next to the utilization units 3a, 3b, ... The refrigerant gas sent to the utilization units 3a, 3b,. It exchanges heat with the indoor air through the heat exchangers on the use side 32a, 32b,., and condenses. The condensed refrigerant is connected to the liquid refrigerant communication pipe 4 by means of the expansion valves on the use side 31a, 31b, ..., and is shipped next to the heat source units 2a to 2c. The liquid refrigerant flowing through the liquid refrigerant communication tubing 4 exchanges heat with the outside air through the heat exchangers on the side of the heat source 24a to 24c of the heat source units 2a to 2c, and evaporation is caused. The evaporated refrigerant gas enters the compression mechanism 21a to 21c again through the four-way switching valves 23a to 23c of the heat source units 2a to 2c. The heating operation is carried out in this way.

<Coolant quantity determination operation>

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

(Refrigerant leak detection operation)

The refrigerant leak detection operation, which is one of the refrigerant quantity determination operation, will be described with reference to figs. 1 and 2. Aqrn, FIG. 2 is a flow chart of the refrigerant leak detection operation.

As an example, a case will be described in which the operation commutes periodically (for example, once a month, when it is not necessary to process load in the air conditioning space, or at another time) to the operation of leak detection of refrigerant, which is a refrigerant quantity determination operation, during the refrigeration operation or the heating operation during normal operation, so that a detection is carried out to determine if the refrigerant within the refrigerant circuit 7 is leaking outwards for unknown reasons.

First, in step S1, a coolant quantity determination preparation operation is carried out before the refrigerant leak detection operation. The refrigerant quantity determination preparation operation will be described later.

Then, in step S2, a determination is made as to whether an operation during normal operation such as the refrigeration operation or the heating operation described above has continued for a fixed time interval (eg, one month), and the process continues to the next step S2 when an operation during normal operation has continued for a fixed time interval.

In step S3, when an operation during normal operation has continued for a fixed time interval, the refrigerant circuit 7 enters a state in which the four-way switching valves 23a to 23c of the heat source units 2a to 2c are in the state indicated by the continuous lines of FIG. 1, the expansion valves on the utilization side 31a, 31b, of the utilization units 3a, 3b, ... are opened, the compression mechanisms 21a to 21c and the outer fan (not shown) are activated, and are carries out a refrigeration operation in all use units 3a, 3b, ...

In step S4, the condensation pressure control is carried out by an external fan, the overheating control by the expansion valves of the use side 31a, 31b, .., and the evaporation pressure control by the compression mechanisms 21a to 21c and the state of the refrigerant circulating within the refrigerant circuit 7 is stabilized.

In step S5, the degree of subcooling at the heat exchanger outputs on the side of the heat source 24a to 24c is detected.

In step S6, the degree of subcooling detected in step S5 is used to determine if the amount of refrigerant is adequate. It can be determined whether the amount of refrigerant charged in the refrigerant circuit 7 is adequate when the degree of subcooling is detected in step S5 using the degree of subcooling of the

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refrigerant at the heat exchanger outlets on the side of the heat source 24a to 24c without relation to the mode of the use units 3a, 3b, ... and the length of the refrigerant communication pipe Kquido 4 and the gaseous refrigerant communication tube 5.

The amount of refrigerant in the heat exchangers on the side of the heat source 24a to 24c is at a low level when the amount of additional charge refrigerant is low and the amount of refrigerant required is not achieved (which specifically indicates that the degree of subcooling detected in step S5 is less than a degree of subcooling that corresponds to the amount of refrigerant that is required for the condensation pressure of the heat exchangers on the side of the heat source 24a to 24c). It is determined that there is no refrigerant leakage when the degree of subcooling detected in step S5 is substantially the same degree (for example, the difference between the degree of subcooling detected and the degree of objective subcooling is less than a predetermined degree) than the predetermined target subcooling degree, and the refrigerant leak detection operation is terminated.

On the other hand, when the degree of subcooling detected in step S5 is a degree that is less than the degree of objective subcooling (for example, the difference between the degree of subcooling detected and the degree of objective subcooling is a predetermined or greater degree ), it is determined that a refrigerant leak has occurred. The process continues to the processing of step S7, and an alarm is displayed that provides a notification that a refrigerant leak has been detected, so that the refrigerant leak detection operation is terminated.

(Automatic refrigerant charge operation)

The automatic refrigerant charging operation as one of the refrigerant quantity determination operation will be described with reference to FIGS. 1 and 3. Aqrn, FIG. 3 is a flow chart of the automatic refrigerant charging operation.

As an example, a case will be described in which a refrigerant circuit 7 is assembled at the installation site by connecting the utilization units 3a, 3b, ... and the heat source units 2a to 2c filled with coolant in advance they are connected by the liquid coolant communication tubing 4 and the gaseous refrigerant communication tubing 5, and the missing refrigerant is subsequently added and charged into the refrigerant circuit 7 according to the length of the tubena of liquid refrigerant communication 4 and the gaseous refrigerant communication tubing 5.

First, the stop valves of the liquid side 25a to 25c and the stop valves of the gas side 26a to 26c of the heat source units 2a to 2c open, and the refrigerant charged in advance in the units of Heat source 2a to 2c is introduced into the refrigerant circuit 7.

Next, the person who carries out the refrigerant charge job sends a command to carry out an automatic refrigerant charge operation, which is one of the refrigerant quantity determination operation, by remote control or directly to the use-side controllers (not shown) of the use units 3a, 3b, ... or the operation controllers 6a to 6c of the heat source units 2a to 2c, so that the automatic refrigerant charge operation it is carried out according to the sequence of step S11 to step S14.

In step S11, the refrigerant quantity determination preparation operation is carried out before the automatic refrigerant charging operation. The refrigerant quantity determination preparation operation will be described later.

In step S12, when a command has been issued to start the automatic refrigerant charging operation, the refrigerant circuit 7 enters a state in which the four-way switching valves 23a to 23c of the source units of heat 2a to 2c are in the state indicated by the continuous lines of FIG. 1, the expansion valves of the utilization side 31a, 31b, of the utilization units 3a, 3b, ... are open, the compression mechanisms 21a to 21c and the outer fan (not shown) are actuated, and are carries out a refrigeration operation in all use units 3a, 3b, ...

In step S13, the condensation pressure control is carried out by an external fan, the superheat control by the expansion valves of the use side 31a, 31b, ..., and the evaporation pressure control by the compression mechanisms 21a to 21c and the state of the refrigerant circulating within the refrigerant circuit 7 is stabilized.

In step S14, the degree of subcooling at the heat exchanger outlets on the side of the heat source 24a to 24c is detected.

In step S15, the degree of subcooling detected in step S14 is used to determine if the amount of refrigerant is adequate. Specifically, when the degree of subcooling detected in step S14 is lower

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that the target subcooling degree and the refrigerant charge is not complete, the processing of step S13 and step S14 is repeated until the subcooling degree reaches the target subcooling degree.

The automatic refrigerant charging operation can be carried out when refrigerant is charged during a test operation after on-site installation, and can also be used to carry out an additional refrigerant charge when the amount of refrigerant charged in the circuit Refrigerant 7 has been reduced due to a refrigerant leak or the like.

<Coolant quantity determination preparation operation>

In the refrigerant quantity determination operation described above, the refrigerant stagnation determination means 8a to 8c determine that the refrigerant has stagnated within the compression mechanisms 21a to 21c when the temperature detected by the temperature sensors 61a to 61c is less than a predetermined temperature, and sends a signal indicating the refrigerant stagnation to the operation controller 6a. Operation controller 6a, which has received a signal from the refrigerant stagnation determination means 8a to 8c, preliminary carries out a control (coolant unclogging operation) so that the compressors 22a to 22c, 27a to 27c, and 28a to 28c get hot enough.

In FIG. 4, the operation controller 6a determines in step S21 if the temperature within the compression mechanisms 21a to 21c measured by the temperature sensors 61a to 61c is less than a predetermined temperature. When the compressor temperature is less than the predetermined temperature, the process continues to step S22, and when the temperature is not less than the predetermined temperature, the process continues to step S23. The operation of refrigerant de-stagnation is carried out in step S22, and the process continues to step S23. In step S23 an oil return operation is carried out. When the oil return operation is completed, the process continues to step s2 in the event that the refrigerant quantity determination operation is a refrigerant leak detection operation, and the process continues to step S12 in case The operation of determining the amount of refrigerant is an automatic operation of refrigerant charging.

(Refrigerant de-stagnation operation)

Here, the refrigerant de-stagnation operation of step S22 described above will be described. The operation controller 6a issues a drive command to all compression mechanisms 21a to 21c of the heat source units 2a to 2c when a signal is received from the means for determining the refrigerant stagnation 8a to 8c. In relation to the heat source units 2b and 2c, however, the operating controllers 6b and 6c, which are subordinate devices, receive the commands of the parent operating controller 6a and issue a drive command to the compression mechanisms 21b and 21c.

In FIG. 5, the compressors 22a to 22c are driven in step S31 and the process continues to step S32. In step S32, the compressors 22a to 22c stop 15 minutes after step S31, the compressors 27a to 27c are operated, and the process continues to step S33. In step S33, the compressors 27a to 27c stop 15 minutes after step S32, the compressors 28a to 28c are operated, and the process continues to step S34. In step S34, the compressors 28a to 28c stop 15 minutes after step S33, and the coolant clearing operation ends.

(Oil return operation)

The oil return operation of step S23 is carried out when the refrigerant clearing operation described above ends, or when the temperature of the compressors in step S21 is greater than a predetermined temperature. Here, the oil return operation will be described with reference to FIG. 6.

In step S41, the operation controller 6a issues a command to drive one of the compressors (i.e., the compressors 22a to 22c) of the heat source units 2a to 2c. In relation to the heat source units 2b and 2c, however, the operation controllers 6a and 6b, which are subordinate devices, receive the commands of the parent operation controller 6a and the subordinate operation controllers 6b and 6c issue a command drive to compression mechanisms 22b and 22c. When step S41 ends, the process continues to step S42. In step S42, the operation controller 6a issues a stop command after the compressors 22a to 22c have been operated for 5 minutes. The oil accumulated in the refrigerant circuit 7 can thus be returned to the compression mechanism 21a to 21c.

<characteristics>

(one)

In the air conditioner 1, the refrigerant stagnation determination means make a determination in advance about whether refrigerant has stagnated in the refrigeration machine oil inside the compressors 22a to 22c, 27a to 27c, and 28a to 28c when the refrigerant quantity determination operation is carried out. Operation controller 6a carries out the operation of refrigerant de-stagnation

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when the means for determining refrigerant stagnation determine that refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanisms 21a to 21c. Therefore, in the air conditioner 1, the determination operation can be carried out after having eliminated the accumulation of refrigerant in the oil of the refrigeration machine within the compression mechanisms 21a to 21c. For this reason, the amount of refrigerant that dissolves in the oil of the refrigeration machine within the compression mechanisms 21a to 21c can be reduced and the error of prediction of the amount of refrigerant can be reduced during the operation of determining quantity of refrigerant. As the refrigerant stagnation in the refrigeration machine oil can consequently be avoided in the compression mechanisms 21a to 21c during the refrigerant quantity determination operation, a more precise refrigerant quantity determination operation becomes possible.

(2)

In the air conditioner 1, the determination of the means for determining refrigerant stagnation is carried out based on the temperature within the compression mechanisms 21a to 21c. For this reason, the temperature inside the compressors 22a to 22c, 27a to 27c, and 28a to 28c can be measured and it is possible to determine if refrigerant has stagnated in the oil of the refrigeration machine within the compression mechanisms 21a to 21c .

(3)

In the air conditioner 1, the compressors 22a to 22c, 27a to 27c, and 28a to 28c are heated for a first predetermined time interval in the refrigerant de-stagnation operation. Therefore, the refrigerant de-stagnation operation involves operating the compressors 22a to 22c, 27a to 27c, and 28a to 28c for a first predetermined time interval, so that the compression mechanisms 21a to 21c can be heated (heating operation ). The interior of the compression mechanisms 21a to 21c can consequently be sufficiently heated and the refrigerant stagnation in the oil of the refrigeration machine within the compression mechanisms 21a to 21c can be eliminated.

(4)

A plurality of heat source units 2a to 2c are present in the air conditioner 1. Therefore, the lifetime of the entire system can be extended if a load is applied exclusively to a single unit even during low-load operation because the heat source units 2a to 2c of the system can be arranged in rotation and actuated according to Time intervals set one unit at a time.

(5)

In the air conditioner 1, the compression mechanisms 21a to 21 have a plurality of compressors 22a to 22c, 27a to 27c, and 28a to 28c. Therefore, the capacity of the compression mechanisms 21a to 21c can be modified by controlling the number of compressors 22a to 22c, 27a to 27c, and 28a to 28c. Therefore, all heat source units 2a to 2c can be operated continuously and the accumulation of refrigerant and oil in the refrigerant circuit 7 can be avoided as much as possible even when the operating load of the the utilization units 3a, 3b, ... In addition, the remaining compressors can handle the load even if one of the compressors 22a to 22c, 27a to 27c, and 28a to 28c fails. For this reason, a complete stop of the air conditioner can be avoided.

(6)

In the air conditioner 1, all compressors 22a to 22c, 27a to 27c, and 28a to 28c can be operated in rotation one unit at a time during a second predetermined time interval when there are a plurality of compressors 22a to 22c, 27a to 27c , and 28a to 28c. Since the refrigeration operation can be carried out when the outside temperature is low during the refrigerant de-stagnation operation, it is difficult to operate all compressors 22a to 22c, 27a to 27c, and 28a to 28c at the same time due to the low level of load. For this reason, the units are operated one unit at a time for a second predetermined time interval, so that all compressors 22a to 22c, 27a to 27c, and 28a to 28c can be operated in advance.

(7)

In the air conditioner 1, an oil return operation is also carried out after the refrigerant clearing operation. In the oil return operation, a control is carried out so that the refrigerant flow rate in the tubenas can be adjusted to a predetermined or greater flow rate. Therefore, the oil that is accumulated in the refrigerant circuit 7 can also be returned by also carrying out an oil return operation. The oil accumulated in the refrigerant circuit 7 can be reliably returned to the compressors 22a to 22c, 27a to 27c, and 28a to 28c. The operation of determining the amount of refrigerant can therefore be carried out with greater precision.

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<Other embodiments>

An embodiment of the present invention has been described above with reference to the drawings; however, the specific configuration is not limited to the mode of realization, and modifications can be made within a range that does not deviate from the main concept of the invention.

(TO)

In the embodiment described above, those air-cooled heat source units 2a to 2c whose outside air is used as the heat source are used as the heat source units 2a to 2c of the air conditioner 1, although also You could use a water-cooled or ice-stored heat source unit.

(B)

In the embodiment described above, the air conditioner 1 can switch between the cooling and heating operation, although it is also possible to use an air conditioner dedicated to refrigeration or an air conditioner that can perform a simultaneous cooling operation and heating.

(C)

In the embodiment described above, three heat source units 2a to 2c having the same air conditioning capacity were connected in parallel, but heat source units having a different air conditioning capacity may be used, and two or more heat source units can also be connected in parallel without restriction to three units.

(D)

In the embodiment described above, operation controllers 6a to 6c are housed in the heat source units 2a to 2c, although it is possible to have a single operation controller such as the complete air conditioner.

(AND)

In the embodiment described above, the means for determining refrigerant stagnation determined whether refrigerant had stagnated in the compressors 22a to 22c, 27a to 27c, and 28a to 28c based on the outside air temperature, but the determination can be carried out. based on the temperature within the compression mechanisms 21a to 21c, it can be carried out by acquiring information about the weather from an external server 10 that provides information about the weather through the internet or other communication line 9 and making a determination based on the information (FIG. 7) on the meteorological time, or it can be carried out based on a time interval of refrigerant stagnation in which it is predicted that the refrigerant stalls easily in the compressors 22a a 22c, 27a to 27c, and 28a to 28c.

(F)

In the embodiment described above, a plurality of heat source units 2a to 2c were used, although there is no limitation as to a plurality of units, and a single unit could be used.

(G)

In the embodiment described above, three compressors 22a to 22c, 27a to 27c, and 28a to 28c were operated for 15 minutes each during the refrigerant de-stagnation operation, although the time interval may be 5, 10, 20 , or 30, without being limited to 15 minutes. It is not necessary to operate all compressors 22a to 22c, 27a to 27c, and 28a to 28c, and at least one compressor that has not been driven can be operated and operated during the refrigerant quantity determination operation.

(H)

In the embodiments described above, the refrigerant de-stagnation operation was carried out using a heating operation in which the compressors 22a to 22c, 27a to 27c, and 28a to 28c are operated to heat the compression mechanisms 21a to 21c, although there is no limitation in this regard, and the compression mechanisms 21a to 21c can be heated using a heater.

(I)

In the embodiment described above, an oil return operation is carried out immediately after the refrigerant de-stagnation operation, although it is not strictly necessary to carry out an oil return operation.

5 Industrial application

The air conditioner of the present invention can eliminate the refrigerant stagnation in the oil of the refrigeration machine within a compression mechanism before a refrigerant quantity determination operation. As a very precise refrigerant quantity determination operation can be carried out, the present invention is useful as a refrigerant circuit of an air conditioner, an air conditioner provided therewith, and other air conditioners.

Claims (13)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. An air conditioner (1) comprising: a refrigerant circuit (7) having a heat source unit (2a to 2c) that has a compression mechanism (21a to 21c) and a heat exchanger on the side of the heat source (24a to 24c), a refrigerant communication pipe (4, 5) to which the heat source unit (2a to 2c), an expansion mechanism (29a to 29c, 31a, 31b, ...), and a utilization unit is connected (3a, 3b, ...) that has a heat exchanger on the use side (32a, 32b, ...) and that is connected to the refrigerant communication pipe (4, 5), refrigerant stagnation determination means (8a to 8c) configured to determine if a refrigerant is stagnant in an oil of the refrigeration machine within the compression mechanism (21a to 21c); and an operation controller (6a to 6c), characterized in that said controller is configured to carry out a refrigerant run-off operation to eliminate the refrigerant stagnation in the oil of the refrigeration machine in the event that the means of Determination of refrigerant stagnation (8a to 8c) has determined in advance that the refrigerant is stagnant in the oil of the refrigeration machine inside the compression mechanism (21a to 21c) before an amount determination operation is carried out of refrigerant to determine an amount of refrigerant in the refrigerant circuit. 2. The air conditioner (1) according to claim 1, characterized in that the means for determining refrigerant stagnation (8a to 8c) carry out a determination based on a temperature within the compression mechanism (21a to 21c). 3. The air conditioner (1) according to claim 1, characterized in that the means for determining refrigerant stagnation (8a to 8c) make a determination based on the temperature of the outside air. 4. The air conditioner (1) according to claim 1, characterized in that the means for determining coolant stagnation (8a to 8c) are connected to a network (9), acquire information about the meteorological time through the network (9), and make a determination based on the weather information. 5. The air conditioner (1) according to claim 1, characterized in that the means for determining refrigerant stagnation (8a to 8c) perform a determination based on a refrigerant stagnation interval in which it is predicted that the Coolant stalls easily inside the compression mechanism (21a to 21c). 6. The air conditioner (1) according to any one of claims 1 to 5, characterized in that the operation controller (6a to 6c) carries out a control to operate the compression mechanism (21a to 21c) during a first predetermined time interval as the refrigerant de-stagnation operation. 7. The air conditioner (1) according to any of claims 1 to 6, characterized in that the plurality of heat source units (2a to 2c) is present. 8. The air conditioner (1) according to any one of claims 1 to 7, characterized in that the compression mechanism (21a to 21c) has a plurality of compressors (22a to 22c, 27a to 27c, 28a to 28c) . 9. The air conditioner (1) according to claim 8, characterized in that the refrigerant de-stagnation operation is an operation to drive at least one compressor (22a to 22c, 27a to 27c, 28a to 28c) that is not It operates during the operation to determine the amount of refrigerant. 10. The air conditioner (1) according to claim 8, characterized in that the refrigerant de-stagnation operation is an operation in which the operation controller (6a to 6c) operates all compressors (22a to 22c, 27a at 27c, 28a to 28c) one at a time in sequence for a second predetermined time interval. 11. The air conditioner (1) according to claim 1, characterized in that it further comprises a heater for heating the compression mechanism (21a to 21c), in which the operation of refrigerant de-stagnation is an operation for heating the compression mechanism (21a to 21c) using the heater. 12. The air conditioner (1) according to any one of claims 1 to 11, characterized in that the operation controller (6a to 6c) also performs an oil return operation immediately after the operation of unblocking of refrigerant. 13. The air conditioner (1) according to claim 12, characterized in that the oil return operation is an operation for controlling the refrigerant flowing through the refrigerant circuit (7) so that the refrigerant flows inside of the tubenas at a predetermined or higher rate.