WO2017094594A1

WO2017094594A1 - Refrigeration device

Info

Publication number: WO2017094594A1
Application number: PCT/JP2016/084858
Authority: WO
Inventors: 卓也北尾; 明敏上野; 東近藤
Original assignee: ダイキン工業株式会社
Priority date: 2015-11-30
Filing date: 2016-11-24
Publication date: 2017-06-08

Abstract

In order to inhibit incomplete melting of frost in the lower part of a frosted service-side heat exchanger (51) during a defrosting operation in the reverse cycle of a refrigeration device, and also to prevent the configuration and control of the device from becoming complicated, dynamic pressure resistance is generated in a capillary tube (56) connected at least to those coolant paths (51a-51n) in the service-side heat exchanger (51) that are positioned below a diverter (55). The dynamic pressure resistance is greater than the head difference between the coolant path to which the capillary tube (56) is connected and the diverter (55).

Description

Refrigeration equipment

The present invention relates to a refrigeration apparatus having a refrigerant circuit in which a reverse cycle defrosting operation is performed, and particularly to a technique for suppressing frost from remaining in the lower part of a frosted heat exchanger during the defrosting operation. .

Conventionally, a refrigeration apparatus that performs a defrosting operation in which a refrigerant is circulated in a reverse cycle is known in order to remove frost from a heat exchanger frosted in a refrigeration cycle. Here, the refrigeration device includes a cooling device that cools the interior of the refrigerator, an air conditioner that heats the room under conditions of low outside air, and the like.

For example, Patent Document 1 discloses a configuration in which a supercooling coil is provided in a lower part of an outdoor heat exchanger of an air conditioner, and a bypass pipe branched from a discharge gas pipe of a compressor is connected to the supercooling coil. The bypass pipe is provided with an electromagnetic valve (open / close valve) and a throttle mechanism (capillary tube).

In this air conditioner, during the reverse cycle defrosting operation performed when the outdoor heat exchanger (evaporator) is frosted during the heating operation, the high-temperature gas refrigerant discharged from the compressor is each refrigerant of the outdoor heat exchanger. While passing through the path, a part of the high-temperature gas refrigerant is diverted from the discharge gas piping of the compressor and flows through the supercooling coil. As described above, in the technique disclosed in Patent Document 1, a high-temperature gas refrigerant is caused to flow through the supercooling coil during the defrosting operation in the reverse cycle, thereby preventing unmelted frost in the lower part of the heat exchanger.

JP 2007-232274 A

Here, in the technique of Patent Document 1, when the evaporator is frosted during the heating operation, heat exchange is difficult to proceed, and liquid refrigerant accumulates in the lower part of the evaporator. Then, when the operation is switched in this state and the reverse cycle defrosting operation is started, the liquid refrigerant is accumulated in the lower path of the heat exchanger and the gas refrigerant has a large passage resistance. Therefore, the gas refrigerant discharged from the compressor Flows through the upper path of the heat exchanger. If the defrosting operation is continued as it is, the frost attached to the upper path of the heat exchanger is removed, but the frost attached to the lower path remains without being removed. Therefore, even if the defrosting operation is completed, frost remains in the lower part of the heat exchanger. As described above, in the conventional technology, in the reverse cycle defrosting operation, the frost is not melted in the lower portion where the liquid refrigerant is accumulated in the frosted heat exchanger.

Further, in the technique of Patent Document 1, since the bypass pipe provided with an electromagnetic valve and a capillary tube is provided in the refrigerant circuit, the configuration of the refrigerant circuit becomes complicated. Further, an operation such as opening a solenoid valve is required during the reverse cycle defrosting operation, and the control becomes complicated. As described above, in the technique of Patent Document 1, the device configuration and control may be complicated.

This invention is made | formed in view of such a problem, The objective is to suppress that frost remains at the lower part of the frosted heat exchanger at the time of defrost operation of a reverse cycle. .

The first aspect of the present disclosure includes one or more compressors (21a, 21b), a first heat exchanger (23), an expansion mechanism (53), and a second heat exchanger (51). The first heat exchanger (23) serves as a radiator and the second heat exchanger (51) serves as an evaporator, and includes a refrigerant circuit (15) that performs a cooling operation in a positive cycle, and is attached to the second heat exchanger (51). When frost is formed, the refrigerant discharged from the compressor (21a, 21b) is supplied to the second heat exchanger (51) to perform a reverse cycle defrosting operation, and a plurality of the second heat exchangers (51) are arranged from above to below. The refrigerant path (51a to 51n) and the flow divider (55) and the refrigerant path (51a to 51n) provided between the expansion mechanism (53) and the second heat exchanger (51) are capillary. It assumes a refrigeration system connected by a tube (56).

The refrigeration apparatus includes a capillary connected to a refrigerant path (51a to 51n) positioned at least below the flow divider (55) among the refrigerant paths (51a to 51n) of the second heat exchanger (51). The tube (56) is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). It is said.

In this first aspect, among the refrigerant paths (51a to 51n) of the second heat exchanger (51), at least the capillary connected to the refrigerant path (51a to 51n) located below the flow divider (55). The tube (56) is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). In the conventional refrigeration system, the capillary tube (56) connected to the refrigerant path (51a to 51n) located below the flow divider (55) is connected to the refrigerant path (51a to 51n) to which the capillary tube (56) is connected. ) And the shunt (55) have a smaller dynamic pressure resistance than the head difference. Therefore, during the defrosting operation, the refrigerant hardly flows to the flow divider (55) through the capillary tube (56) connected to the path below the heat exchanger, and the refrigerant path (51a to 51n) below the heat exchanger. However, in this first aspect, since the dynamic pressure resistance is set as described above, the flow velocity is increased and the head difference is reduced. The refrigerant flows to the flow divider (55) through the capillary tube (56) connected to the lower path of the heat exchanger, so the liquid refrigerant flows into the refrigerant path (51a to 51n) below the heat exchanger. Does not remain. Therefore, the unmelted frost in the lower part of the heat exchanger can be suppressed.

According to a second aspect of the present disclosure, in the first aspect, a capillary tube (56) that connects the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) includes: It is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the lowermost refrigerant path (51n) and the flow divider (55), and all capillary tubes (56) have the same inner diameter and the same length. It is a feature.

In this second embodiment, the capillary tube (56) connecting the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) is connected to the lowermost refrigerant path (51n). ) And the flow divider (55) are configured as a throttle that generates a dynamic pressure resistance larger than the head difference, and all capillary tubes (56) have the same inner diameter and the same length, so that the path below the heat exchanger Therefore, it is possible to prevent liquid refrigerant from remaining in the refrigeration, so that frost remaining in the lower portion of the heat exchanger can be suppressed.

According to a third aspect of the present disclosure, in the second aspect, a temperature sensor (75) that detects a temperature of a refrigerant flowing through a pipe on the downstream side of the flow divider (55) during the defrosting operation is provided. It is characterized by.

In this third aspect, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the flow divider (55) from each refrigerant path (51a to 51n) of the second heat exchanger (51) is determined by the temperature sensor (75). Is detected. In this temperature sensor (75), the entire amount of refrigerant after passing through the flow divider (55) during reverse cycle operation flows, and when the refrigerant temperature exceeds a predetermined value, the lowermost refrigerant path It can be judged that (51n) frost has melted.

According to a fourth aspect of the present disclosure, in the first to third aspects, a capillary tube (51) connected to the flow path (51a to 51n) of the flow divider (55) and the second heat exchanger (51). 56) is characterized in that it is formed in a shape having a refrigerant trap (59) passing through the height below the lowermost refrigerant path (51n).

Here, generally, when the reverse cycle defrosting operation is started, the liquid refrigerant is accumulated in the lower path of the heat exchanger, so that the gas refrigerant discharged from the compressor (21a, 21b) Follow the upper path. If the defrosting operation is continued as it is, frost attached to the upper path of the heat exchanger is removed, but frost attached to the lower path may remain without being removed. Therefore, even if the defrosting operation is completed, it is considered that frost remains in the lower part of the heat exchanger.

On the other hand, in the fourth aspect, by providing the capillary tube (56) with the refrigerant trap (59), the liquid refrigerant in the lowermost refrigerant path (51n) only becomes the passage resistance of the gas refrigerant. In the upper refrigerant path (51a to 51n), the liquid refrigerant accumulated in the refrigerant trap (59) becomes a resistance, so that the refrigerant passes through each refrigerant path (51a to 51n) of the second heat exchanger (51). It flows evenly. Therefore, when switching from the normal operation to the defrosting operation, the gas refrigerant flows easily through each path, and only the upper refrigerant path (51a to 51n) is prevented from flowing through the lower refrigerant path. In addition, since the gas refrigerant can be supplied, the frost attached to the lower path can be surely removed.

A fifth aspect of the present disclosure includes one or more compressors (21a, 21b), a first heat exchanger (23), an expansion mechanism (53), and a second heat exchanger (51). The first heat exchanger (23) serves as a radiator and the second heat exchanger (51) serves as an evaporator, and includes a refrigerant circuit that performs a cooling operation in the positive cycle. When the second heat exchanger (51) is frosted, the refrigerant is compressed. The refrigerant discharged from the machine (21a, 21b) is supplied to the second heat exchanger (51) to perform a defrosting operation in the reverse cycle, and the second heat exchanger (51) has a plurality of refrigerant paths extending from above to below. (51a to 51n), and a flow divider (55) and a refrigerant path (51a to 51n) provided between the expansion mechanism (53) and the second heat exchanger (51) include a capillary tube (56 ) Is assumed to be connected to the refrigeration system.

In this refrigeration apparatus, the capillary tube (56) connected to the flow divider (55) and the refrigerant path (51a to 51n) of the second heat exchanger (51) has a lower refrigerant path (51n ) It is formed in the shape provided with the refrigerant | coolant trap (59) which passes the following height.

Here, as described above, generally, when the reverse cycle defrosting operation is started, the liquid refrigerant is accumulated in the lower path of the heat exchanger and the passage resistance of the gas refrigerant is large, so that the compressor (21a, 21b The gas refrigerant discharged from the gas flows through the upper path of the heat exchanger. If the defrosting operation is continued as it is, frost attached to the upper path of the heat exchanger is removed, but frost attached to the lower path may remain without being removed. Therefore, even if the defrosting operation is completed, it is considered that frost remains in the lower part of the heat exchanger.

On the other hand, in the fifth aspect, by providing the capillary tube (56) with the refrigerant trap (59), the liquid refrigerant in the lowermost refrigerant path (51n) only becomes the passage resistance of the gas refrigerant. In the upper refrigerant path (51a to 51n), the liquid refrigerant accumulated in the refrigerant trap (59) becomes a resistance, so that the refrigerant passes through each refrigerant path (51a to 51n) of the second heat exchanger (51). It will flow evenly. Therefore, when switching from the normal operation to the defrosting operation, the gas refrigerant flows easily through each path, and only the upper refrigerant path (51a to 51n) is prevented from flowing through the lower refrigerant path. In addition, since the gas refrigerant can be supplied, the frost attached to the lower path can be surely removed.

A sixth aspect of the present disclosure is characterized in that, in the fifth aspect, the flow divider (55) is arranged with the connection portion of the capillary tube (56) facing downward.

In the sixth aspect, in the configuration in which the flow divider (55) is arranged with the connecting portion of the capillary tube (56) facing downward, the normal operation is defrosted as in the fifth aspect. When switching to, the gas refrigerant easily flows through each path evenly. Accordingly, since the gas refrigerant can be supplied to the lower path by preventing the gas refrigerant from flowing only through the upper refrigerant path (51a to 51n), the frost attached to the lower path can be surely removed.

In a seventh aspect of the present disclosure, in the fifth or sixth aspect, the shape of all the refrigerant traps (59) of the capillary tube (56) is the same as the height of the lower end of the capillary tube (56). It is characterized by that.

In the seventh aspect, in the configuration in which all the refrigerant traps (59) of the capillary tube (56) are defined so that the lower ends of the capillary tubes (56) have the same height, As in the sixth aspect, the gas refrigerant easily flows through each path even when the normal operation is switched to the defrosting operation. Accordingly, since the gas refrigerant can be supplied to the lower path by preventing the gas refrigerant from flowing only through the upper refrigerant path (51a to 51n), the frost attached to the lower path can be surely removed.

According to an eighth aspect of the present disclosure, in the first or fifth aspect, a supercooling coil (57) is provided below the second heat exchanger (51), and the supercooling coil (57) The refrigerant inflow side end (57a) during the cycle cooling operation communicates directly with the liquid line (15L) of the refrigerant circuit, and the refrigerant inflow side end (57b) during the reverse cycle defrosting operation The refrigerant path (51a to 51n) of the second heat exchanger (51) is communicated with the flow divider (55).

In the eighth aspect, during the reverse cycle defrosting operation, the high-temperature gas refrigerant discharged from the compressor (21a, 21b) is supplied to the frosted second heat exchanger (51). At this time, if the liquid refrigerant is accumulated in the lower refrigerant path (51a to 51n) of the second heat exchanger (51), the gas refrigerant flows through the upper path and then passes through the flow divider (55), and further It flows through the supercooling coil (57). As a result, at the start of the defrosting operation, the high-temperature gas refrigerant occupies most of the refrigerant flowing through the supercooling coil (57), and the liquid refrigerant hardly flows. Therefore, since the high-temperature gas refrigerant that occupies most of the refrigerant flow flows through the supercooling coil, the temperature of the supercooling coil rises, and the second heat exchanger (51) is warmed from the bottom. As the defrosting operation is continued, the refrigerant path (51a to 51n) through which the high-temperature gas refrigerant flows expands downward from the uppermost refrigerant path (51a to 51n), so the second heat exchanger ( 51) is also warmed from top to bottom. Thus, in the eighth aspect, the second heat exchanger (51) is heated from both above and below, so that not only frost adhering to the upper refrigerant path (51a to 51n) but also the lower refrigerant path ( Frost adhering to 51a-51n) is also removed.

According to a ninth aspect of the present disclosure, in the eighth aspect, the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) are connected during the defrosting operation. A temperature sensor (75) for detecting the temperature of the refrigerant flowing through the capillary tube (56) is provided.

In the ninth aspect, during the reverse cycle defrosting operation, the capillary tube (56) connected to the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) is connected. The temperature of the flowing refrigerant is detected by the temperature sensor (75). And when this temperature is equal to or higher than a predetermined value, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. That is, it can be determined that the frost on the use side heat exchanger has melted as a whole.

According to a tenth aspect of the present disclosure, in the eighth aspect, the temperature sensor (75) detects the temperature of the refrigerant that has passed through the supercooling coil (57) of the second heat exchanger (51) during the defrosting operation. It is characterized by having.

In the tenth aspect, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the supercooling coil (57) of the second heat exchanger (51) is detected by the temperature sensor (75). In the supercooling coil (57) of the second heat exchanger (51), the entire amount of refrigerant after passing through the flow divider (55) during reverse cycle operation flows, and the temperature of the refrigerant reaches a predetermined value or more. If so, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. Specifically, when the reverse cycle defrosting operation is started, almost only the gas refrigerant flows through the supercooling coil (57) and is at a high temperature, but when the frost of the use side heat exchanger starts to melt. When the temperature of the refrigerant once decreases and the frost melts further, the temperature of the refrigerant increases. Therefore, when the temperature of the refrigerant when rising is equal to or higher than a predetermined value, it can be determined that the frost attached to the lowermost refrigerant path (51n) has melted.

An eleventh aspect of the present disclosure includes the internal unit (12) including the expansion mechanism (53) and the second heat exchanger (51) in the ninth or tenth aspect, and the temperature sensor ( 75) is provided in the interior unit (12).

In the eleventh aspect, has the defrosting operation been completed using the temperature sensor (75) provided in the internal unit (12) having the expansion mechanism (53) and the second heat exchanger (51)? Whether it can be detected.

According to the first aspect of the present disclosure, among the refrigerant paths (51a to 51n) of the second heat exchanger (51), at least the refrigerant paths (51a to 51n) positioned below the flow divider (55). The connected capillary tube (56) is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). As a result, the flow rate of the refrigerant is increased, the head difference is overcome, and the refrigerant flows through the capillary tube (56) connected to the path below the heat exchanger to the flow divider (55). The liquid refrigerant does not stay in the refrigerant path (51a to 51n) below. Therefore, it is possible to suppress frost from being melted at the lower part of the frosted heat exchanger during the defrosting operation.

Further, according to the first aspect, a bypass pipe provided with an electromagnetic valve or a capillary tube (56) is connected to the refrigerant circuit (15), or an operation of opening the electromagnetic valve during a reverse cycle defrosting operation is performed. Since it is not necessary, the configuration and control can be prevented from becoming complicated.

According to the second aspect of the present disclosure, the capillary tube (56) that connects the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) is connected to the lowermost heat exchanger (51). The heat exchanger is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51n) and the flow divider (55), and all capillary tubes (56) have the same inner diameter and the same length. Since the liquid refrigerant can be prevented from remaining in the lower path, the configuration of the apparatus can be simplified, and frost remaining in the lower part of the heat exchanger can be suppressed.

According to the third aspect of the present disclosure, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the flow divider (55) from each refrigerant path (51a to 51n) of the second heat exchanger (51) is the temperature. If it is detected by the sensor (75) and the temperature of the refrigerant is equal to or higher than a predetermined value, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. In this temperature sensor (75), since the entire amount of refrigerant after passing through the flow divider (55) flows during the reverse cycle operation, it can be accurately determined whether or not the defrosting operation has ended.

According to the fourth aspect of the present disclosure, by providing the capillary tube (56) with the refrigerant trap (59), not only the liquid refrigerant in the lowermost refrigerant path (51n) becomes the passage resistance of the gas refrigerant. In the upper refrigerant path (51a to 51n), the liquid refrigerant accumulated in the refrigerant trap (59) becomes resistance, so that the refrigerant is evenly distributed in each refrigerant path (51a to 51n) of the second heat exchanger (51). To flow into. Therefore, the gas refrigerant can easily flow through each path, and the gas refrigerant can be supplied to the lower paths by preventing the gas refrigerant from flowing only through the upper refrigerant paths (51a to 51n). Therefore, when switching from the normal operation to the defrosting operation, it is possible to suppress the drift caused by the separation of the refrigerant into the gas phase and the liquid phase, so that the liquid phase refrigerant accumulates in the frosted heat exchanger. In addition, it is possible to prevent frost from remaining unmelted in the refrigerant path (51a to 51n) below.

According to the fifth to seventh aspects of the present disclosure, by providing the capillary tube (56) with the refrigerant trap (59), the liquid refrigerant in the lowermost refrigerant path (51n) becomes the passage resistance of the gas refrigerant. In addition to the upper refrigerant paths (51a to 51n), the liquid refrigerant accumulated in the trap (59) becomes resistance, so that the refrigerant paths (51a to 51a) of the second heat exchanger (51) 51n) refrigerant flows evenly. Therefore, the gas refrigerant can easily flow through each path, and the gas refrigerant can be supplied to the lower paths by preventing the gas refrigerant from flowing only through the upper refrigerant paths (51a to 51n). Therefore, when switching from the normal operation to the defrosting operation, it is possible to suppress the drift that the gas refrigerant flows through only the refrigerant path at the upper part of the heat exchanger, so that the liquid refrigerant tends to accumulate in the frosted heat exchanger. It is possible to prevent frost from remaining unmelted in the refrigerant paths (51a to 51n).

According to the eighth aspect of the present disclosure, during the defrosting operation, the second heat exchanger (51) is warmed from both above and below, so frost adhering to the upper part of the second heat exchanger (51). In addition, frost attached to the lower portion of the second heat exchanger (51) can be removed. That is, it is possible to prevent frost from remaining unmelted.

Moreover, according to the 8th aspect, it is not necessary to connect the bypass piping which provided the solenoid valve and the capillary tube (56) to the refrigerant circuit, or to open the solenoid valve during the reverse cycle defrosting operation. Therefore, it is possible to prevent the configuration and control from becoming complicated.

According to the ninth aspect of the present disclosure, the capillary tube connected to the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) during the defrosting operation in the reverse cycle. Since the temperature of the refrigerant flowing through (56) is detected by the temperature sensor (75) and this temperature is equal to or higher than a predetermined value, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. It can be detected whether or not.

According to the tenth aspect of the present disclosure, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the supercooling coil (57) of the second heat exchanger (51) is detected by the temperature sensor (75), If this temperature exceeds a predetermined value after a predetermined time from the start of the defrosting operation, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. Can do. Further, if the temperature sensor (75) is provided at a position after passing through the supercooling coil (57), the temperature can be detected from the total flow rate of the refrigerant, so that the end of the defrosting operation can be detected more accurately.

According to the eleventh aspect of the present disclosure, the defrosting operation is performed using the temperature sensor (75) provided in the internal unit (12) including the expansion mechanism (53) and the second heat exchanger (51). Therefore, it is possible to detect whether or not the defrosting operation has ended, by using only the in-compartment unit (12).

FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 1 of the present invention. FIG. 2 is a circuit configuration diagram showing details of piping around the use side heat exchanger. FIG. 3 is a graph showing the pipe diameters of the ratio of the length and pipe diameter of the flow divider capillary tube and the refrigerant circulation amount. FIG. 4 is a diagram illustrating a refrigerant flow in the cooling operation in the refrigerant circuit of FIG. 1. FIG. 5 is a diagram illustrating a refrigerant flow in a reverse cycle defrosting operation in the refrigerant circuit of FIG. 1. FIG. 6 is a circuit configuration diagram showing details of piping around the use side heat exchanger of the refrigeration apparatus according to another embodiment. FIG. 7 is a circuit configuration diagram illustrating details of piping around the use-side heat exchanger according to the second embodiment. FIG. 8 is a diagram illustrating a modification of the connection form between the use-side heat exchanger and the flow divider in the second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
A first embodiment of the present invention will be described.

FIG. 1 shows a configuration example of the refrigeration apparatus (10) according to the first embodiment. The refrigeration apparatus (10) includes a heat source side unit (11) provided outside the storage, a use side unit (12) provided in a storage such as a refrigerator or a freezer, and a controller (80). The heat source side unit (11) includes a heat source side circuit (16) and a heat source side fan (17), and the usage side unit (12) includes a usage side circuit (18), a usage side fan (19), and Is provided. In this refrigeration system (10), the heat source side circuit (16) of the heat source side unit (11) and the usage side circuit (18) of the usage side unit (12) are connected to the liquid side communication pipe (13) and the gas side communication pipe ( 14), a refrigerant circuit (15) in which a refrigerant circulates and a vapor compression refrigeration cycle is performed is configured. Specifically, a liquid closing valve (V1) and a gas closing valve (V2) are provided at the liquid end and the gas end of the heat source side circuit (16), respectively, and the liquid closing valve (V1) and the gas closing valve (V2) One end of the liquid side connecting pipe (13) and one end of the gas side connecting pipe (14) are connected to the other end of the liquid side connecting pipe (13) and the gas side connecting pipe (14). The liquid end and the gas end are connected to each other.

<Heat source side circuit>
The heat source side circuit (16) includes a first compressor (21a) and a second compressor (21b), a four-way switching valve (22), a heat source side heat exchanger (23), and a supercooling heat exchanger (24 ), Supercooling expansion valve (31), intermediate expansion valve (32), intermediate on-off valve (33), intermediate check valve (34), receiver (35), and heat source side expansion valve (36) A first check valve (CV1), a second check valve (CV2), a third check valve (CV3), a first oil separator (OSa) and a second oil separator (OSb), 1 discharge check valve (CVa) and 2nd discharge check valve (CVb), 1st capillary tube (CTa) and 2nd capillary tube (CTb), and oil separation check valve (CVc) Yes.

The heat source side circuit (16) includes a discharge refrigerant pipe (41), an intake refrigerant pipe (42), a heat source side liquid refrigerant pipe (43), an injection pipe (44), and a first connection pipe (45). ) And a second connection pipe (46), and an oil return pipe (47).

The first compressor (21a) is configured to compress and discharge the sucked refrigerant. The first compressor (21a) is provided with a suction port, an intermediate port, and a discharge port. The suction port is formed so as to communicate with the compression chamber (that is, the low-pressure compression chamber) in the suction stroke of the first compressor (21a). The intermediate port is formed so as to communicate with the compression chamber (that is, the compression chamber of intermediate pressure) during the compression stroke of the first compressor (21a). The discharge port is configured to communicate with the compression chamber (that is, the high-pressure compression chamber) in the discharge stroke of the first compressor (21a). For example, the first compressor (21a) is configured by a scroll compressor in which a compression chamber is formed between a fixed scroll and a movable scroll that mesh with each other. The second compressor (21b) has a configuration similar to that of the first compressor (21a).

The first compressor (21a) has a variable operating frequency (capacity). In other words, the first compressor (21a) is configured such that by changing the output frequency of the inverter (not shown), the rotational speed of the motor provided therein changes, and the operating frequency changes. ing. On the other hand, the operating frequency (capacity) of the second compressor (21b) is fixed. That is, as for the 2nd compressor (21b), the rotation speed of the electric motor provided in the inside is constant, and the operating frequency is constant.

The four-way switching valve (22) includes a first state (state indicated by a solid line in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other, And the fourth port are in communication with each other and the second port and the third port are in communication with each other (a state indicated by a broken line in FIG. 1).

The first port of the four-way switching valve (22) is connected to the discharge ports of the first and second compressors (21a, 21b) by the discharge refrigerant pipe (41), and the second port of the four-way switching valve (22) is The suction refrigerant pipe (42) is connected to the suction ports of the first and second compressors (21a, 21b). The third port of the four-way switching valve (22) is connected to the gas end of the heat source side heat exchanger (23), and the fourth port of the four-way switching valve (22) is connected to the gas closing valve (V2). .

The discharge refrigerant pipe (41) has first and second discharge pipes (41a, 41b) whose one ends are connected to discharge ports of the first and second compressors (21a, 21b), and first and second discharge pipes. It is comprised by the discharge main pipe (41c) which connects the other end of (41a, 41b) and the 1st port of the four-way selector valve (22).

The suction refrigerant pipe (42) has first and second suction pipes (42a, 42b) connected at one end to the suction ports of the first and second compressors (21a, 21b), respectively, and the first and second suction pipes. The suction main pipe (42c) connects the other end of the pipe (42a, 42b) and the second port of the four-way selector valve (22).

The liquid end of the heat source side heat exchanger (23) is connected to one end of the heat source side liquid refrigerant pipe (43), and the gas end is connected to the third port of the four-way switching valve (22). Moreover, the heat source side fan (17) is arrange | positioned in the vicinity of the heat source side heat exchanger (23). The heat source side heat exchanger (23) is configured to exchange heat between the refrigerant and the heat source side air (that is, outside air) conveyed by the heat source side fan (17). For example, the heat source side heat exchanger (23) is configured by a cross-fin type fin-and-tube heat exchanger.

The heat source side liquid refrigerant pipe (43) has one end connected to the heat source side heat exchanger (23) and the other end connected to the liquid closing valve (V1). In this example, the heat source side liquid refrigerant pipe (43) includes a first heat source side liquid pipe (43a) that connects the liquid end of the heat source side heat exchanger (23) and the receiver (35), and a receiver (35). A second heat source side liquid pipe (43b) connecting the supercooling heat exchanger (24), and a third heat source side liquid pipe (43c) connecting the supercooling heat exchanger (24) and the liquid shut-off valve (V1). ) And.

The injection pipe (44) connects the first intermediate part (Q1) of the heat source side liquid refrigerant pipe (43) and the intermediate ports of the first and second compressors (21a, 21b). In this example, the injection pipe (44) includes a first injection main pipe (44m) that connects the first intermediate part (Q1) of the heat source side liquid refrigerant pipe (43) and the supercooling heat exchanger (24), and one end. The second injection main pipe (44n) connected to the supercooling heat exchanger (24), the other end of the second injection main pipe (44n), and the intermediate ports of the first and second compressors (21a, 21b). The first and second injection branch pipes (44a, 44b) are connected to each other.

The supercooling heat exchanger (24) is connected to the heat source side liquid refrigerant pipe (43) and the injection pipe (44), and includes a refrigerant flowing through the heat source side liquid refrigerant pipe (43) and a refrigerant flowing through the injection pipe (44). Are configured to exchange heat. In this example, the supercooling heat exchanger (24) includes a first flow path (24a) connected between the second heat source side liquid pipe (43b) and the third heat source side liquid pipe (43c), The second flow path (24b) connected between the 1 injection main pipe (44m) and the second injection main pipe (44n), and the refrigerant flowing through the first flow path (24a) and the second flow path (24b ) To exchange heat. For example, the supercooling heat exchanger (24) is configured by a plate heat exchanger.

The supercooling expansion valve (31) is located between the first intermediate part (Q1) of the heat source side liquid refrigerant pipe (43) and the supercooling heat exchanger (24) in the injection pipe (44) (in this example, the first It is provided in the injection main pipe (44m). Further, the supercooling expansion valve (31) is configured such that its opening degree can be adjusted. For example, the supercooling expansion valve (31) is constituted by an electronic expansion valve (motorized valve).

The intermediate expansion valve (32) is located between the supercooling heat exchanger (24) and the intermediate port of the first compressor (21a) in the injection pipe (44) (in this example, the first injection branch pipe (44a)). Is provided. Further, the intermediate expansion valve (32) is configured so that its opening degree can be adjusted. For example, the intermediate expansion valve (32) is configured by an electronic expansion valve (motorized valve).

The intermediate on-off valve (33) and the intermediate check valve (34) are disposed between the supercooling heat exchanger (24) and the intermediate port of the second compressor (21b) in the injection pipe (44) (in this example, the first 2 injection branch pipe (44b)). In the second injection branch pipe (44b), an intermediate on-off valve (33) and an intermediate check valve (34) are sequentially arranged from the inlet side to the outlet side of the second injection branch pipe (44b).

The intermediate on-off valve (33) is configured to be switchable. For example, the intermediate opening / closing valve (33) is constituted by a solenoid valve. The intermediate check valve (34) is configured to allow the refrigerant flow from the inlet side to the outlet side of the second injection branch pipe (44b) and to block the refrigerant flow in the reverse direction.

The receiver (35) is connected between the heat source side heat exchanger (23) and the supercooling heat exchanger (24) in the heat source side liquid refrigerant pipe (43), and is connected to a condenser (specifically, heat source side heat In the exchanger (first heat exchanger) (23) or a later-described use side heat exchanger (second heat exchanger) (51)), the condensed refrigerant can be temporarily stored. . In this example, the receiver (35) has a first heat source side liquid pipe (43a) connected to the inlet and a second heat source side liquid pipe (43b) connected to the outlet.

The first connection pipe (45) connects the second midway part (Q2) and the third midway part (Q3) of the heat source side liquid refrigerant pipe (43). The second halfway part (Q2) is located between the first halfway part (Q1) and the liquid shut-off valve (V1) in the heat source side liquid refrigerant pipe (43), and the third halfway part (Q3) is located on the heat source side It is located between the liquid end of the heat source side heat exchanger (23) and the receiver (35) in the liquid refrigerant pipe (43).

The second connection pipe (46) connects the fourth midway part (Q4) and the fifth midway part (Q5) of the heat source side liquid refrigerant pipe (43). The fourth midway part (Q4) is located between the first halfway part (Q1) and the second halfway part (Q2) in the heat source side liquid refrigerant pipe (43), and the fifth halfway part (Q5) is located on the heat source side The liquid refrigerant pipe (43) is located between the liquid end of the heat source side heat exchanger (23) and the third midway part (Q3).

The heat source side expansion valve (36) is provided in the second connection pipe (46). Moreover, the heat source side expansion valve (36) is comprised so that the opening degree can be adjusted. For example, the heat source side expansion valve (36) is configured by an electronic expansion valve (motorized valve).

The first check valve (CV1) is provided between the third midway part (Q3) and the fifth midway part (Q5) of the heat source side liquid refrigerant pipe (43), and the first check valve (CV1) 3. The refrigerant flow toward the middle part (Q3) is allowed and the refrigerant flow in the opposite direction is blocked.

The second check valve (CV2) is provided between the second midway part (Q2) and the fourth midway part (Q4) of the heat source side liquid refrigerant pipe (43), and the second midway part (Q4) to the second midway part (Q4). 2 The refrigerant flow toward the middle part (Q2) is allowed and the refrigerant flow in the opposite direction is blocked.

The third check valve (CV3) is provided in the first connection pipe (45), and the refrigerant flows from the second midway part (Q2) to the third midway part (Q3) of the heat source side liquid refrigerant pipe (43). And the refrigerant flow in the opposite direction is blocked.

The first oil separator (OSa) and the first discharge check valve (CVa) are disposed between the first compressor (21a) and the first port of the four-way switching valve (22) in the discharge refrigerant pipe (41) (specifically Specifically, it is provided in the first discharge pipe (41a). In the first discharge pipe (41a), a first oil separator (OSa) and a first discharge check valve (CVa) are sequentially arranged from the inlet side to the outlet side of the first discharge pipe (41a). . The first oil separator (OSa) is configured to separate the refrigerating machine oil from the refrigerant discharged from the first compressor (21a) and store it inside. The first discharge check valve (CVa) is configured to allow the flow of the refrigerant from the inlet side to the outlet side of the first discharge pipe (41a) and prevent the refrigerant flow in the reverse direction.

The second oil separator (OSb) is disposed between the second compressor (21b) and the first port of the four-way switching valve (22) in the discharge refrigerant pipe (41) (specifically, the second discharge pipe (41b )). In the second discharge pipe (41b), a second oil separator (OSb) and a second discharge check valve (CVb) are sequentially arranged from the inlet side to the outlet side of the second discharge pipe (41b). . The second oil separator (OSb) is configured so that the refrigeration oil can be separated from the refrigerant discharged from the second compressor (21b) and stored inside. The second discharge check valve (CVb) is configured to allow the refrigerant flow from the inlet side to the outlet side of the second discharge pipe (41b) and to block the refrigerant flow in the reverse direction.

The oil return pipe (47) is a pipe for supplying the refrigeration oil stored in the first and second oil separators (OSa, OSb) to the injection pipe (44). In this example, the oil return pipe (47) includes first and second oil return pipes (47a, 47b) whose one ends are connected to the first and second oil separators (OSa, OSb), and the first and second oil return pipes (47). 2. Oil return main pipe (47c) connecting the other end of the oil return pipe (47a, 47b) and the middle part of the injection pipe (44) (specifically, the middle part (Q6) of the second injection main pipe (44n)) ) And.

The first capillary tube (CTa) is located between the first oil separator (OSa) and the middle part (Q6) of the injection pipe (44) in the oil return pipe (47) (specifically, the first oil return pipe). (47a)).

The second capillary tube (CTb) and oil return check valve (CVc) are located between the second oil separator (OSb) and the middle part (Q6) of the injection pipe (44) in the oil return pipe (47). Specifically, the second oil return pipe (47b) is provided. In the second oil return pipe (47b), an oil return check valve (CVc) and a second capillary tube (CTb) are sequentially arranged from the inlet side to the outlet side of the second oil return pipe (47b). . The oil return check valve (CVc) is configured to allow the refrigerant flow from the inlet side to the outlet side of the second oil return pipe (47b) and to block the refrigerant flow in the reverse direction.

<User side circuit>
The utilization side circuit (18) includes a utilization side heat exchanger (51), a utilization side on-off valve (52), a utilization side expansion valve (expansion mechanism) (53), and a utilization side check valve (54). Have. Further, the use side circuit (18) is provided with a use side liquid refrigerant pipe (61), a use side gas refrigerant pipe (62), and a bypass pipe (63). In addition, FIG. 1 has simplified and shown the utilization side heat exchanger (51) and piping connected to the utilization side heat exchanger (51).

The liquid end of the use side heat exchanger (51) is connected to the liquid side connection pipe (13) by the use side liquid refrigerant pipe (61), and the gas end is connected to the gas side by the use side gas refrigerant pipe (62). Connected to pipe (14). Moreover, the utilization side fan (19) is arrange | positioned in the vicinity of the utilization side heat exchanger (51). The use side heat exchanger (51) is configured to exchange heat between the refrigerant and the use side air (that is, the internal air) conveyed by the use side fan (19). For example, the use side heat exchanger (51) is configured by a cross-fin type fin-and-tube heat exchanger.

The use side liquid refrigerant pipe (61) has one end connected to the liquid side communication pipe (13) and the other end connected to the liquid end of the use side heat exchanger (51). The use side gas refrigerant pipe (62) has one end connected to the gas end of the use side heat exchanger (51) and the other end connected to the gas side communication pipe (14).

The use side opening / closing valve (52) and the use side expansion valve (53) are provided in the use side liquid refrigerant pipe (61). In the use side liquid refrigerant pipe (61), a use side on-off valve (52) and a use side expansion valve (53) are arranged in this order from one end side to the other end side of the use side liquid refrigerant pipe (61). .

The use side on-off valve (52) is configured to be switchable. For example, the use side on-off valve (52) is constituted by a solenoid valve. The use side expansion valve (53) is configured such that its opening degree can be adjusted. In this example, the use side expansion valve (53) is constituted by an external pressure equalization type temperature automatic expansion valve. That is, the use side expansion valve (53) includes a temperature sensing cylinder (53a) provided in the use side gas refrigerant pipe (62) and a pressure equalizing pipe (not shown) connected to the middle part of the use side gas refrigerant pipe (62). The opening degree is adjusted according to the temperature of the temperature sensing cylinder (53a) and the refrigerant pressure of the pressure equalizing pipe.

One end of the bypass pipe (63) is connected to a midway part between the use side expansion valve (53) and the use side heat exchanger (51) in the use side liquid refrigerant pipe (61), and the other end is used. The liquid refrigerant pipe (61) is connected to a midway part between the liquid side connecting pipe (13) and the use side on-off valve (52).

The use-side check valve (54) is provided in the bypass pipe (63) and allows the refrigerant to flow from the use-side heat exchanger (51) side to the liquid-side connecting pipe (13) side, and in the opposite direction. It is configured to block the flow of the refrigerant.

Next, details of the usage-side heat exchanger (51) and details of refrigerant pipe connection to the usage-side heat exchanger (51) will be described. Although omitted in FIG. 1, the use side heat exchanger (51) has a plurality of refrigerant paths (51a to 51n) arranged from the top to the bottom as shown in FIG. Further, a flow divider (55) is connected between the use side expansion valve (53) and the use side heat exchanger (51), and the flow divider (55) and each refrigerant path (51a to 51n) are connected to the capillary. They are connected by tubes (56 (56a to 56n)).

In this refrigeration apparatus (10), a capillary tube (56) connected to a refrigerant path located at least below the flow divider (55) among the refrigerant paths (51a to 51n) of the use side heat exchanger (51). However, it is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). Specifically, as shown in FIG. 3, the value obtained by adding the dynamic pressure resistances of the capillary tube (56) and the cooling pipes (refrigerant paths) (51a to 51n) is the shunt (55) and the lowermost refrigerant path. The length and the diameter of the capillary tube (56) are determined so as to be larger than the head difference (ΔPHi) of (51n). As a result, the flow rate of the refrigerant increases, and the refrigerant flows through the capillary tube (56) by overcoming the head difference.

In particular, in this embodiment, the capillary tube (56n) that connects the lowermost refrigerant path (51n) of the use side heat exchanger (51) and the flow divider (55) includes the lowermost refrigerant path (51n). ) And the flow divider (55) are configured as a throttle that generates a dynamic pressure resistance larger than the head difference, and all the capillary tubes (56a to 56n) have the same inner diameter and the same length.

The use side circuit (18) is provided with a temperature sensor (75) for detecting the temperature of the refrigerant flowing in the downstream pipe of the flow divider (55) during the defrosting operation. Further, as described above, the refrigeration apparatus (10) is a refrigeration having a use side unit (internal unit) (12) including the use side expansion valve (53) and a use side heat exchanger (51). The temperature sensor (75) is a device, and is provided inside the use side unit (12).

<Various sensors>
The refrigeration apparatus (10) is provided with various sensors such as an intake temperature sensor (71), an intake pressure sensor (72), and an internal temperature sensor (73).

The suction temperature sensor (71) is configured to detect the temperature of the refrigerant sucked into the first and second compressors (21a, 21b) (hereinafter referred to as “suction temperature”). In this example, the suction temperature sensor (71) is installed in the suction main pipe (42c) and detects the refrigerant temperature at the installation location as the suction temperature.

The suction pressure sensor (72) is configured to detect the pressure of the refrigerant sucked into the first and second compressors (21a, 21b) (hereinafter referred to as “suction pressure”). In this example, the suction pressure sensor (72) is installed in the suction main pipe (42c) and detects the refrigerant pressure at the installation location as the suction pressure.

The internal temperature sensor (73) is configured to detect the temperature of air in the internal space (hereinafter referred to as “internal temperature (Tr)”). In this example, the internal temperature sensor (73) is installed upstream of the air flow of the usage-side fan (19) in the usage-side unit (12) and detects the air temperature at the installation location as the internal temperature (Tr). To do.

<controller>
The controller (80) controls the operation of the refrigeration apparatus (10) by controlling each part of the refrigeration apparatus (10) based on the detection values of the various sensors. In this example, the controller (80) includes a main controller (81) provided in the heat source side unit (11) and a use side controller (82) provided in the use side unit (12).

The main controller (81) controls the components provided in the heat source side unit (11). In this example, the heat source side fan (17) provided in the heat source side unit (11), various valves (in this example, a four-way switching valve (22), a supercooling expansion valve (31), an intermediate expansion valve (32), The intermediate on-off valve (33), the heat source side expansion valve (36)), the first compressor (21a), the second compressor (21b), and the like are controlled, and the target evaporation temperature is also set.

The usage side controller (82) controls the components (in this example, the usage side fan (19) and the usage side on-off valve (52)) provided in the usage side unit (12).

Further, the use side controller (82) determines whether or not the operation of the refrigeration apparatus (10) should be started, and if it determines that the operation of the refrigeration apparatus (10) should be started, the cooling operation (cools the inside of the refrigerator) For starting the operation) and an operation start signal is transmitted to the main controller (81). Further, the use side controller (82) determines whether or not the operation of the refrigeration apparatus (10) should be terminated, and when determining that the operation of the refrigeration apparatus (10) should be terminated, the operation for the cooling operation is performed. At the same time, an operation end signal is transmitted to the main controller (81). For example, the use side controller (82) determines the operation start and operation end of the refrigeration apparatus (10) in response to an operation by the user (operation for instructing operation start and operation end).

In addition, the use side controller (82) determines whether or not to start the defrosting operation (operation for defrosting the use side heat exchanger (51)) during the period during which the cooling operation is performed, When it is determined that the defrosting operation should be started, an operation for the defrosting operation is started and a defrosting start signal is transmitted to the main controller (81). Further, the use side controller (82) determines whether or not the defrosting operation should be terminated during the period during which the defrosting operation is being performed. And the operation for cooling operation is started, and a defrosting end signal is transmitted to the main controller (81). For example, the use-side controller (82) determines that the defrosting operation should be started when a predetermined time (cooling operation time) elapses from the time when the cooling operation is started, for example, the temperature sensor (75). When the detected temperature reaches a predetermined temperature, it is determined that the defrosting operation should be terminated. It should be noted that when a predetermined time (defrosting operation time) has elapsed since the start of the defrosting operation, it may be determined that the defrosting operation has ended.

As described above, the refrigeration apparatus (10) of the present embodiment includes the compressor (21a, 21b), the heat source side heat exchanger (first heat exchanger) (23), and the use side expansion valve (expansion mechanism) (53 ) And the use side heat exchanger (second heat exchanger) (51), the heat source side heat exchanger (23) becomes a radiator and the use side heat exchanger (51) becomes an evaporator. The refrigeration apparatus includes a refrigerant circuit (15) for operation. The refrigeration apparatus (10) supplies the refrigerant discharged from the compressor (21a, 21b) to the use side heat exchanger (51) when the use side heat exchanger (51) is frosted, thereby removing the reverse cycle. It is configured to perform frost operation.

-Driving operation-
Next, the operation of the refrigeration apparatus (10) will be described.

<Flow of refrigerant during cooling operation>
Next, the refrigerant flow in the refrigerant circuit (15) during the cooling operation will be described with reference to FIG. In the cooling operation, the four-way selector valve (22) is set to the first state, and the discharge ports of the first and second compressors (21a, 21b) communicate with the gas ends of the heat source side heat exchanger (23), The suction ports of the first and second compressors (21a, 21b) communicate with the gas side communication pipe (14).

The refrigerant discharged from the first and second compressors (21a, 21b) is discharged from the first and second oil separators (OSa, OSb) and the first and second discharge check valves (41) in the discharge refrigerant pipe (41). CVa, CVb), and then passes through the four-way switching valve (22) and flows into the heat source side heat exchanger (23). In the heat source side heat exchanger (23), the heat source side air (that is, outside air) ) To dissipate heat and condense. The refrigerant (high-pressure refrigerant) flowing out from the heat source side heat exchanger (23) passes through the first check valve (CV1) in the first heat source side liquid pipe (43a), and then the receiver (35) and the second heat source side. A refrigerant (passing through the liquid pipe (43b) in order and flowing into the first flow path (24a) of the supercooling heat exchanger (24) and flowing through the second flow path (24b) of the supercooling heat exchanger (24) ( The refrigerant is absorbed by the intermediate pressure refrigerant) and supercooled. The refrigerant flowing out of the first flow path (24a) of the supercooling heat exchanger (24) flows into the third heat source side liquid pipe (43c), and part of it flows into the first injection main pipe (44m), The remaining portion passes through the second check valve (CV2) in the third heat source side liquid pipe (43c), then passes through the liquid closing valve (V1) and flows into the liquid side connecting pipe (13).

The refrigerant flowing into the first injection main pipe (44m) is depressurized in the supercooling expansion valve (31), flows into the second flow path (24b) of the supercooling heat exchanger (24), and then enters the supercooling heat exchanger ( Heat is absorbed from the refrigerant (high-pressure refrigerant) flowing through the first flow path (24a) of 24). The refrigerant flowing out from the second flow path (24b) of the supercooling heat exchanger (24) passes through the second injection main pipe (44n), and part of it flows into the first injection branch pipe (44a). The remaining part flows into the second injection branch pipe (44b). The refrigerant flowing into the first injection branch pipe (44a) is decompressed by the intermediate expansion valve (32) and flows into the intermediate port of the first compressor (21a). The refrigerant flowing into the second injection branch pipe (44b) sequentially passes through the intermediate opening / closing valve (33) and the intermediate check valve (34) and flows into the intermediate port of the second compressor (21b). The refrigerant that has passed through the intermediate port and has flowed into the first and second compressors (21a, 21b) is the refrigerant in the first and second compressors (21a, 21b) (specifically, the refrigerant in the compression chamber). ). That is, the refrigerant in the first and second compressors (21a, 21b) is compressed while being cooled.

On the other hand, the refrigerant flowing into the liquid side communication pipe (13) passes through the open use side on-off valve (52) in the use side liquid refrigerant pipe (61) of the use side unit (12) and passes through the use side expansion valve (52). 53), the pressure is reduced and flows into the use-side heat exchanger (51), and the use-side heat exchanger (51) absorbs heat from the use-side air (that is, the internal air) to evaporate. Thereby, utilization side air is cooled. The refrigerant flowing out of the use side heat exchanger (51) is divided into the use side gas refrigerant pipe (62), the gas side connecting pipe (14), the gas shutoff valve (V2) and the four-way switching valve (22) of the heat source side unit (11). ) And the suction refrigerant pipe (42) in order, and is sucked into the suction ports of the first and second compressors (21a, 21b).

In the first and second oil separators (OSa, OSb), the refrigeration oil is separated from the refrigerant (that is, the refrigerant discharged from the first and second compressors (21a, 21b)). It is stored in the first and second oil separators (OSa, OSb). The refrigerating machine oil stored in the first oil separator (OSa) flows into the oil return main pipe (47c) after passing through the first capillary tube (CTa) in the first oil return pipe (47a). The refrigerating machine oil stored in the second oil separator (OSb) passes through the oil return check valve (CVc) and the second capillary tube (CTb) in order in the second oil return pipe (47b), and then returns to the oil. It flows into the main pipe (47c). The refrigeration oil that has flowed into the oil return main pipe (47c) flows into the second injection main pipe (44n) and merges with the refrigerant flowing through the second injection main pipe (44n).

<Flow of refrigerant during defrosting operation>
Next, with reference to FIG. 5, the flow of the refrigerant in the refrigerant circuit (15) during the defrosting operation will be described. In the defrosting operation, the four-way switching valve (22) is set to the second state, the discharge ports of the first and second compressors (21a, 21b) and the gas side communication pipe (14) communicate with each other. The suction port of the second compressor (21a, 21b) and the gas end of the heat source side heat exchanger (23) communicate with each other.

The refrigerant discharged from the first and second compressors (21a, 21b) is discharged from the first and second oil separators (OSa, OSb) and the first and second discharge check valves (41) in the discharge refrigerant pipe (41). After passing through CVa, CVb), the gas passes through the four-way switching valve (22) and the gas shut-off valve (V2) in order, and flows into the gas side connecting pipe (14). The refrigerant that has flowed into the gas side communication pipe (14) passes through the use side gas refrigerant pipe (62) of the use side unit (12) and flows into the use side heat exchanger (51). In 51), it dissipates heat and condenses. Thereby, the frost adhering to the use side heat exchanger (51) is heated and melted. A part of the refrigerant flowing out of the use side heat exchanger (51) passes between the open use side expansion valve (53) and the open use side on-off valve (52) in the use side liquid refrigerant pipe (61). Passing in order, the remainder passes through the use side check valve (54) in the bypass pipe (63). The refrigerant that has passed through the open-side use-side on-off valve (52) in the use-side liquid refrigerant pipe (61) joins the refrigerant that has passed through the use-side check valve (54) in the bypass pipe (63), and communicates with the liquid side. It flows into the pipe (13).

The refrigerant that has passed through the liquid side connection pipe (13) passes through the liquid shut-off valve (V1) of the heat source side unit (11), flows into the first connection pipe (45), and enters the first connection pipe (45). 3 It passes through the check valve (CV3) and flows into the middle part (third middle part (Q3)) of the first heat source side liquid pipe (43a). The refrigerant that has flown into the middle of the first heat source side liquid pipe (43a) passes through the receiver (35), the second heat source side liquid pipe (43b), and the first flow path (24a) of the supercooling heat exchanger (24). And then flows into the third heat source side liquid pipe (43c). The refrigerant that has flowed into the third heat source side liquid pipe (43c) flows into the second connection pipe (46) in the fourth midway portion (Q4), and is depressurized in the heat source side expansion valve (36) to be first heat source side liquid. It flows into the middle part (5th middle part (Q5)) of the pipe (43a). The refrigerant that has flown into the middle part of the first heat source side liquid pipe (43a) flows into the heat source side heat exchanger (23), and from the heat source side air (that is, outside air) in the heat source side heat exchanger (23). It absorbs heat and evaporates. The refrigerant flowing out of the heat source side heat exchanger (23) passes through the four-way switching valve (22) and the suction refrigerant pipe (42) in order, and is sucked into the suction ports of the first and second compressors (21a, 21b). Is done.

The specific operation in the use side heat exchanger (51) during the defrosting operation will be described.

In this embodiment, as described above, the capillary tube connected to the refrigerant path located at least below the flow divider (55) among the refrigerant paths (51a to 51n) of the use side heat exchanger (51). (56) is configured as a throttle that generates a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). In the conventional refrigeration system, the capillary tube (56) connected to the refrigerant path (51a to 51n) located below the flow divider (55) is connected to the refrigerant path (51a to 51n) to which the capillary tube (56) is connected. ) And the shunt (55) produce a smaller dynamic pressure resistance than the head difference. Therefore, during the defrosting operation, the refrigerant does not flow to the flow divider (55) through the capillary tube (56) connected to the refrigerant path below the user side heat exchanger (51), and the user side heat exchanger. Liquid refrigerant remains in the refrigerant path below (51), causing frost to remain undissolved. On the other hand, in this embodiment, since the dynamic pressure resistance is set as described above, the flow velocity of the refrigerant is increased, the head difference is overcome, and the connection is made to the path below the use-side heat exchanger (51). Since the refrigerant flows through the capillary tube (56) to the flow divider (55), the liquid refrigerant does not stay in the refrigerant path below the use side heat exchanger (51). Therefore, the unmelted frost in the lower part of the use side heat exchanger (51) can be suppressed.

In particular, in this embodiment, the capillary tube (56) connecting the lowermost refrigerant path (51n) of the use side heat exchanger (51) and the flow divider (55) is connected to the lowermost refrigerant path (51n). ) And the flow divider (55) as a throttle that generates a dynamic pressure resistance larger than the head difference, and all the capillary tubes (56) have the same inner diameter and the same length. Therefore, it is possible to simplify the configuration, and it is possible to prevent liquid refrigerant from remaining in the refrigerant path below the usage-side heat exchanger (51), thereby preventing the usage-side heat exchanger (51). Frost at the bottom of the frost can be suppressed.

In the reverse cycle defrosting operation, the temperature sensor (75) detects the temperature of the refrigerant that has passed through the flow divider (55) from each refrigerant path of the use side heat exchanger (51). In the portion where the temperature sensor (75) is provided, the entire amount of refrigerant after passing through the flow divider (55) during reverse cycle operation flows, and when the temperature of the refrigerant is equal to or higher than a predetermined value, It can be determined that the frost in the lowermost refrigerant path (51n) has melted.

-Effect of Embodiment 1-
According to the present embodiment, the capillary tube (56) connected to the refrigerant path positioned at least below the flow divider (55) among the refrigerant paths (51a to 51n) of the use side heat exchanger (51) is provided. The flow rate of the refrigerant is increased by configuring the throttle as a dynamic pressure resistance larger than the head difference between the refrigerant path (51a to 51n) to which the capillary tube (56) is connected and the flow divider (55). The head difference is overcome, and the refrigerant can flow to the flow divider (55) through the capillary tube (56) connected to the refrigerant path below the use side heat exchanger (51). Therefore, since the liquid refrigerant does not stay in the refrigerant path below the use side heat exchanger (51), it is possible to suppress the frost in the lower part of the frosted use side heat exchanger (51) from remaining unmelted during the defrosting operation. be able to.

In particular, according to the above embodiment, the capillary tube (56) that connects the lowermost refrigerant path (51n) of the use side heat exchanger (51) and the flow divider (55) is connected to the lowermost refrigerant path. (51n) and the flow divider (55) are configured as a throttle that generates a dynamic pressure resistance larger than the head difference, and all capillary tubes (56) have the same inner diameter and length, making the system configuration simpler In addition, it is possible to prevent liquid refrigerant from remaining in the refrigerant path below the use side heat exchanger (51).

Further, according to the present embodiment, there is no need to connect a bypass pipe provided with an electromagnetic valve or a capillary tube to the refrigerant circuit (18), or to open the electromagnetic valve during a reverse cycle defrosting operation. It is also possible to prevent the configuration and control from becoming complicated.

Further, according to the above embodiment, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the flow divider (55) from each refrigerant path (51a to 51n) of the usage-side heat exchanger (51) is measured by the temperature sensor ( If it is detected at 75) and the temperature of the refrigerant is equal to or higher than a predetermined value, it can be determined that the frost in the lowermost refrigerant path (51n) has melted. In this temperature sensor (75), since the entire amount of refrigerant after passing through the flow divider (55) flows during the reverse cycle operation, it can be accurately determined whether or not the defrosting operation has ended. Further, since it is possible to detect whether or not the defrosting operation has been completed using the temperature sensor (75) provided in the use side unit (12), the end detection of the defrosting operation is completed only by the use side unit. be able to.

-Modification of Embodiment 1-
The temperature sensor (75) is connected to the lowermost refrigerant path (51a) and the flow divider (55) of the use side heat exchanger (51) during the defrosting operation, as indicated by a virtual line in FIG. You may provide in the position which detects the temperature of the refrigerant | coolant which flows through the connected capillary tube (56).

In this modification, during the reverse cycle defrosting operation, the refrigerant flows through the capillary tube (56) connected to the lowermost refrigerant path (51n) of the use side heat exchanger (51) and the flow divider (55). Is detected by the temperature sensor (75). Also in this modified example, if this temperature is equal to or higher than a predetermined value, it can be determined that the frost in the lowermost refrigerant path has melted, so it can be determined whether or not the defrosting operation has ended.

Further, the above embodiment may be configured as follows.

For example, as shown in FIG. 6, the lowermost refrigerant path is connected to the capillary tube (56) connected to the flow divider (55) and the refrigerant path (51a to 51n) of the use side heat exchanger (51). (51n) A refrigerant trap (59) passing through the height below may be formed.

When the capillary tube (56) is provided with the trap (59), frost attached to the refrigerant path below the use side heat exchanger (51) can be surely removed. This point will be described. Generally, when a reverse cycle defrosting operation is started, liquid refrigerant accumulates in the lower path of the use-side heat exchanger (51) and the gas refrigerant has a high resistance to passage, so that it is discharged from the compressor (21a, 21b). The gas refrigerant flows only through the refrigerant path at the top of the use side heat exchanger (51). If the defrosting operation is continued as it is, the frost attached to the upper refrigerant path of the use side heat exchanger (51) is removed, but the frost attached to the lower refrigerant path may remain without being removed. There is. Therefore, even if the defrosting operation is completed, it is considered that frost remains in the lower part of the heat exchanger.

On the other hand, in the present embodiment, by providing a trap (59) in the capillary tube (56), the liquid refrigerant in the lowermost refrigerant path (51n) not only becomes a passage resistance of the gas refrigerant, but also the upper part. In the refrigerant path (51a side refrigerant path), the liquid refrigerant collected in the trap (59) becomes resistance, so that the refrigerant is evenly distributed in each refrigerant path (51a to 51n) of the use side heat exchanger (51). It begins to flow. Therefore, when switching from the normal operation to the defrosting operation, the gas refrigerant easily flows through each refrigerant path (51a to 51n) evenly (difficult to cause a drift), and the gas refrigerant flows only through the upper refrigerant path. Therefore, the gas refrigerant can be supplied also to the lower refrigerant path, so that frost adhering to the lower path can also be reliably removed. That is, it is possible to reliably suppress the frost from remaining unmelted in the lower refrigerant path portion where the liquid-phase refrigerant is accumulated in the frosted use side heat exchanger (51).

In the above embodiment, the plurality of capillary tubes (56) between the use side heat exchanger (51) and the flow divider (55) are all the same length and have the same tube diameter, but the use side heat exchanger The length and diameter of the capillary tube (56) may be set so that the dynamic pressure resistance increases continuously or stepwise from the refrigerant path above (51) toward the refrigerant path below. The capillary tube (56) has a length and a tube diameter within a range in which the pressure loss of the refrigerant does not become excessive during the cooling operation.

<< Embodiment 2 of the Invention >>
A second embodiment of the present invention will be described. Since the refrigerant circuit of Embodiment 2 is the same as Embodiment 1, description is abbreviate | omitted.

As shown in FIG. 7, in the lower part of the use side heat exchanger (51) of the second embodiment, there is a supercooling heat exchanger that functions as a supercooling heat exchanger when the use side heat exchanger (51) becomes an evaporator. A cooling coil (57) is provided. In the subcooling coil (57), the end portion (57a) on the refrigerant inflow side during the cooling operation in the positive cycle is in direct communication with the liquid line (15L) of the refrigerant circuit (15). The supercooling coil (57) has the end portion (57b) on the refrigerant inflow side in the defrosting operation in the reverse cycle connected to the refrigerant path (51a to 51n) of the use side heat exchanger (51). The side check valve (54), the flow divider (55), and the capillary tube (56 (56a to 56n)) communicate with each other. A header (58) where the refrigerant paths (51a to 51n) join is provided on the gas side of the use side heat exchanger (51).

The usage side circuit (18) is provided with a temperature sensor (75) for detecting the temperature of the refrigerant that has passed through the supercooling coil (57) of the usage side heat exchanger (51) during the defrosting operation. . Further, as described above, the refrigeration apparatus (10) is a refrigeration having a use side unit (internal unit) (12) including the use side expansion valve (53) and a use side heat exchanger (51). The temperature sensor (75) is a device, and is provided inside the use side unit (12).

In the utilization side circuit (18) of the refrigeration apparatus (10), capillary tubes (51a to 51n) connected to the flow divider (55) and the refrigerant paths (51a to 51n) of the utilization side heat exchanger (51) 56 (56a to 56n)) is formed in a shape having a refrigerant trap (59) passing through the height below the lowermost refrigerant path (51n).

-Driving operation-
Since the flow of the refrigerant in the refrigerant circuit is the same as that in the first embodiment, a description thereof will be omitted, and a specific operation in the use side heat exchanger (51) during the defrosting operation will be described.

During the reverse cycle defrosting operation, as shown by the broken arrow in FIG. 7, the high-temperature gas refrigerant discharged from the compressor (21a, 21b) is supplied to the frosting use side heat exchanger (51). Is done. At this time, if liquid refrigerant is accumulated in the lower refrigerant path (51n side refrigerant path) of the use side heat exchanger (51), the gas refrigerant flows through the upper refrigerant path (51a side refrigerant path). It passes through the flow divider (55) and further flows through the supercooling coil (57). At the start of the defrosting operation, the refrigerant flowing through the supercooling coil (57) occupies most of the flow rate, and the liquid refrigerant hardly flows. Therefore, since the high-temperature gas refrigerant that occupies most of the refrigerant flow flows through the supercooling coil (57), the temperature of the supercooling coil (57) rises, and the usage-side heat exchanger (51) is warmed from below. As the defrosting operation continues, the refrigerant path through which the high-temperature gas refrigerant flows expands downward from the upper refrigerant path (51a-side refrigerant path), so the use-side heat exchanger (51) It will be warmed down from the bottom. Thus, in this embodiment, since the use side heat exchanger (51) is warmed from both above and below, not only the frost adhering to the upper refrigerant path (51a side refrigerant path) but also the lower refrigerant path. Frost adhering to the (51n-side refrigerant path) can also be removed.

Further, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the supercooling coil (57) of the use side heat exchanger (51) is the temperature sensor (75) provided inside the use side unit (12). Is detected. At this time, the total amount of refrigerant after passing through the flow divider (55) during reverse cycle operation flows through the supercooling coil (57) of the use side heat exchanger (51), and the temperature of the refrigerant is equal to or higher than a predetermined value. It can be determined that the frost in the lowermost refrigerant path (51n) has melted. Specifically, when the reverse cycle defrosting operation is started, only the gas refrigerant flows through the supercooling coil (57) and the temperature is high. When it begins to melt, the temperature of the refrigerant once decreases, and when the frost further melts, the temperature of the refrigerant increases. Therefore, when the temperature of the refrigerant when rising is equal to or higher than a predetermined value, it can be determined that frost has melted up to the lowermost refrigerant path (51n).

In this embodiment, since the refrigerant trap (59) is provided in the capillary tube (56 (56a to 56n)), the refrigerant path (51n side refrigerant path) below the use side heat exchanger (51) is provided. Adhering frost can be removed reliably. This point will be described.

Generally, when a reverse cycle defrosting operation is started, liquid refrigerant accumulates in the refrigerant path (51n side refrigerant path) at the lower part of the use side heat exchanger (51) and the passage resistance of the gas refrigerant is large. The gas refrigerant discharged from (21a, 21b) flows through the upper refrigerant path (51a side refrigerant path) of the use side heat exchanger (51). If the defrosting operation is continued as it is, frost attached to the upper refrigerant path (51a side refrigerant path) of the use side heat exchanger (51) is removed, but the lower refrigerant path (51n side refrigerant path). There is a risk that frost adhering to) may remain without being removed. Therefore, even if the defrosting operation is completed, it is considered that frost remains in the lower part of the heat exchanger.

On the other hand, in the present embodiment, by providing a refrigerant trap (59) in the capillary tube (56 (56a to 56n)), the liquid refrigerant in the lowermost refrigerant path (51n) has a resistance to passage of gas refrigerant. In addition, since the liquid refrigerant accumulated in the refrigerant trap (59) becomes a resistance in the upper refrigerant path (51a side refrigerant path), each refrigerant path (51a to 51a) of the use side heat exchanger (51) 51n) refrigerant flows evenly. Therefore, when switching from the normal operation to the defrosting operation, the gas refrigerant flows easily through each refrigerant path (51a to 51n), and the gas refrigerant flows only through the upper refrigerant path (51a side refrigerant path). Therefore, the gas refrigerant can also be supplied to the lower refrigerant path (51n-side refrigerant path), so that frost attached to the lower refrigerant path (51n-side refrigerant path) can also be reliably removed.

-Effect of Embodiment 2-
According to the present embodiment, by providing the capillary tube (56 (56a to 56n)) with the refrigerant trap (59), the liquid refrigerant in the lowermost refrigerant path (51n) only becomes the passage resistance of the gas refrigerant. In addition, since the liquid refrigerant accumulated in the refrigerant trap (59) becomes resistance also in the upper refrigerant path (51a side refrigerant path), each refrigerant path (51a) of the use side heat exchanger (51) Through 51n), the refrigerant flows evenly. Therefore, the gas refrigerant easily flows through each refrigerant path (51a to 51n), and only the upper refrigerant path (51a side refrigerant path) is prevented from flowing, and the lower refrigerant path (51n side Gas refrigerant can also be supplied to the refrigerant path. Therefore, when the normal operation is switched to the defrosting operation, it is possible to suppress the occurrence of a drift in which the gas refrigerant flows only in the refrigerant path above the heat exchanger in the use side heat exchanger (51). Therefore, it is possible to reliably suppress the frost from remaining in the lower refrigerant path (51n side refrigerant path) where the liquid refrigerant has accumulated in the frosted use side heat exchanger (51). .

Moreover, according to this embodiment, since the use side heat exchanger (51) is warmed from both the upper side and the lower side in the defrosting operation, only the frost adhering to the upper part of the use side heat exchanger (51) is obtained. In addition, it is possible to obtain an effect of removing frost attached to the lower portion of the use side heat exchanger (51).

Furthermore, according to the above embodiment, during the reverse cycle defrosting operation, the temperature of the refrigerant that has passed through the supercooling coil (57) of the use side heat exchanger (51) is provided inside the use side unit (12). The temperature sensor (75) detects that the frost in the lowermost refrigerant path (51n) has melted when a predetermined time has elapsed since the start of the defrosting operation and this temperature has exceeded a predetermined value. Since it can be determined, it can be detected whether the defrosting operation has been completed. As described above, when the temperature sensor (75) is provided at the position after passing through the supercooling coil (57), the temperature can be detected from the total flow rate of the refrigerant, so that the completion of the defrosting operation can be accurately detected. . In addition, since it is possible to detect whether or not the defrosting operation has been completed using the temperature sensor (75) provided in the usage side unit (12), only the usage side unit (12) can detect the completion of the defrosting operation. Can be completed with.

-Modification of Embodiment 2-
The temperature sensor (75) is connected to the lowermost refrigerant path (51n) and the flow divider (55) of the use side heat exchanger (51) during the defrosting operation, as indicated by a virtual line in FIG. You may provide in the position which detects the temperature of the refrigerant | coolant which flows through the connected capillary tube (56n).

In this modification, during the reverse cycle defrosting operation, the refrigerant flows through the capillary tube (56n) connected to the lowermost refrigerant path (51n) of the use side heat exchanger (51) and the flow divider (55). Is detected by the temperature sensor (75). And also in this modified example, when this temperature is equal to or higher than a predetermined value, the frost in the lowermost refrigerant path (56n) has melted (the entire frost in the use side heat exchanger (51) has melted). Therefore, it can be detected whether or not the defrosting operation has been completed.

Further, for example, as shown in FIG. 8, the flow divider (55) may be arranged so that the connection portion of the capillary tube (56a to 56n) faces downward. Also in this configuration, as in the example of FIG. 7, the capillary tube (56a to 56n) is provided with the trap (59) passing through the height below the lowermost refrigerant path (51n). Moreover, the subcooling coil (57) comprised similarly to the example of FIG. 7 is provided in the lower part of the utilization side heat exchanger (51).

Even with this configuration, the same effects as in the above embodiment can be obtained.

Moreover, in the example of FIG. 7, FIG. 8, the supercooling coil (57) is provided in the lower part of the utilization side heat exchanger (51), and the frost adhering to the lower part of the utilization side heat exchanger (51) is made into an upper refrigerant | coolant. The refrigerant gas flowing through the path (51a side refrigerant path) is heated and removed, but the supercooling coil (57) is not necessarily provided. Even if the supercooling coil (57) is not provided, by providing the refrigerant trap (59) in the capillary tube (56a to 56n), the refrigerant drift when switching from the normal cooling operation to the reverse cycle defrosting operation is reduced. Therefore, it is possible to enhance the defrosting effect by causing the gas refrigerant to flow uniformly to the use side heat exchanger (51).

In the example of FIGS. 7 and 8, the capillary tube (56a to 56n) is provided with a trap (59) passing through the height below the lowermost refrigerant path (51n), which is the reverse of the normal cooling operation. The refrigerant is prevented from drifting when switching to the defrosting operation of the cycle to prevent liquid refrigerant from accumulating in the lower refrigerant path (51n side refrigerant path). 59) is not necessarily provided, and the provision of the above supercooling coil (57) without the provision of the trap (59) prevents the frost from remaining in the use side heat exchanger (51). Can be increased as compared with the conventional case.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

For example, although the said embodiment is an example which applied this invention to the freezing apparatus which cools the inside of a store | warehouse | chamber, this invention may be applied to the outdoor heat exchanger of the air conditioning apparatus which heats a room | chamber interior.

In the second embodiment, the supercooling coil may not be provided, and in the first embodiment, the supercooling coil (57) of the second embodiment may be provided.

In addition, the above embodiment is an essentially preferable example, and is not intended to limit the scope of the present invention, its application, or its use.

As described above, the present invention, in a refrigeration apparatus having a refrigerant circuit in which a reverse cycle defrosting operation is performed, suppresses frost from remaining in the lower part of the frosted heat exchanger during the defrosting operation. Useful for.

10 Refrigeration equipment 12 User-side unit (inside unit)
15 Refrigerant circuit

15L Liquid line

21a 1st compressor 21b 2nd compressor 23 Heat source side heat exchanger (1st heat exchanger)
51 User side heat exchanger (second heat exchanger)
51a Refrigerant path 51n Refrigerant path 53 User-side expansion valve (expansion mechanism)
55 Shunt 56 Capillary tube 57 Supercooling coil 59 Refrigerant trap 75 Temperature sensor

Claims

The first heat exchanger (23) includes one or more compressors (21a, 21b), a first heat exchanger (23), an expansion mechanism (53), and a second heat exchanger (51). It has a refrigerant circuit (15) that performs cooling operation in the positive cycle in which the second heat exchanger (51) becomes an evaporator and becomes a radiator. When the second heat exchanger (51) is frosted, the compressor (21a, 21b) To supply the second refrigerant to the second heat exchanger (51) for reverse cycle defrosting operation,
The second heat exchanger (51) has a plurality of refrigerant paths (51a to 51n) from above to below,
A refrigeration apparatus in which a flow divider (55) provided between the expansion mechanism (53) and the second heat exchanger (51) and the refrigerant path (51a to 51n) are connected by a capillary tube (56). There,
The capillary tube (56) connected to the refrigerant path positioned at least below the flow divider (55) among the refrigerant paths (51a to 51n) of the second heat exchanger (51) is the capillary tube (56). A refrigeration apparatus configured as a throttle that generates a dynamic pressure resistance larger than a head difference between the refrigerant path (51a to 51n) and the flow divider (55) connected to each other.
In claim 1,
The capillary tube (56) connecting the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) is connected to the lowermost refrigerant path (51n) and the flow divider (55). It is configured as a diaphragm that generates a dynamic pressure resistance larger than the head difference with
All the capillary tubes (56) are the same internal diameter and the same length, The freezing apparatus characterized by the above-mentioned.
In claim 2,
A refrigeration apparatus comprising a temperature sensor (75) for detecting a temperature of a refrigerant flowing in a pipe downstream of the flow divider (55) during the defrosting operation.
In any one of Claims 1-3,
The capillary tube (56) connected to the flow divider (55) and the refrigerant path (51a to 51n) of the second heat exchanger (51) passes through the height below the lowermost refrigerant path (51n). A refrigeration apparatus having a shape with a refrigerant trap (59).
The first heat exchanger (23) includes one or more compressors (21a, 21b), a first heat exchanger (23), an expansion mechanism (53), and a second heat exchanger (51). A refrigerant circuit that performs a cooling operation in a positive cycle in which the second heat exchanger (51) serves as a radiator and serves as a radiator. When frosted on the second heat exchanger (51), refrigerant discharged from the compressor (21a, 21b) Is supplied to the second heat exchanger (51) to perform a reverse cycle defrosting operation,
The second heat exchanger (51) has a plurality of refrigerant paths (51a to 51n) from above to below,
A refrigeration apparatus in which a flow divider (55) provided between the expansion mechanism (53) and the second heat exchanger (51) and the refrigerant path (51a to 51n) are connected by a capillary tube (56). There,
The capillary tube (56) connected to the flow divider (55) and the refrigerant path (51a to 51n) of the second heat exchanger (51) passes through the height below the lowermost refrigerant path (51n). A refrigeration apparatus having a shape with a refrigerant trap (59).
In claim 4 or 5,
The flow divider (55) is a refrigeration apparatus in which a connection portion of the capillary tube (56) is disposed downward.
In claim 4, 5 or 6,
The refrigeration apparatus characterized in that the shape of all the refrigerant traps (59) of the capillary tube (56) is determined so that the lower ends of the capillary tubes (56) have the same height.
In claim 1 or 5,
A subcooling coil (57) is provided at the lower part of the second heat exchanger (51),
The supercooling coil (57) has a refrigerant inflow side end (57a) directly communicating with the liquid line (15L) of the refrigerant circuit during the forward cycle cooling operation and a refrigerant during the reverse cycle defrosting operation. An inflow side end (57b) communicates with the refrigerant path (51a to 51n) of the second heat exchanger (51) via the flow divider (55).
In claim 8,
A temperature sensor that detects the temperature of the refrigerant flowing through the capillary tube (56) connected to the lowermost refrigerant path (51n) of the second heat exchanger (51) and the flow divider (55) during the defrosting operation. (75) The freezing apparatus characterized by the above-mentioned.
In claim 8,
A refrigeration apparatus comprising a temperature sensor (75) for detecting the temperature of the refrigerant that has passed through the supercooling coil (57) of the second heat exchanger (51) during the defrosting operation.
In claim 9 or 10,
An internal unit (12) including the expansion mechanism (53) and the second heat exchanger (51);
The refrigeration apparatus characterized in that the temperature sensor (75) is provided inside the internal unit (12).