JP2010151392A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve cooling performance of a refrigerating device while reducing compression power of a compressor for supercooling in a supercooling circuit, in the refrigerating device including a refrigerant circuit performing a vapor compression type refrigerating cycle, and the supercooling circuit for supercooling a refrigerant flowing in the refrigerant circuit. <P>SOLUTION: The supercooling circuit (10a) is provided with: intermediate pressure lines (7b, 5) connecting an intermediate pressure expansion valve EV2 connected to a branch pipe (3a) branched from a high pressure liquid line (3) of the supercooling circuit (10a), and an intermediate port provided so as to be opened in a compression chamber at an intermediate pressure position in the compressor (11) for supercooling; a first supercooling heat exchanger (14) disposed over the intermediate pressure lines (7b, 5) and a first liquid side communication pipe of the refrigerant circuit; and a second supercooling heat exchanger (15) disposed over the intermediate pressure lines (7b, 5) and second liquid side communication pipes (80a, 80c) of the refrigerant circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle and a supercooling circuit that performs supercooling of high-pressure refrigerant flowing through the refrigerant circuit.

  Conventionally, a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle and a supercooling circuit that is connected to a supercooling heat exchanger that supercools high-pressure refrigerant flowing through the refrigerant circuit is known.

  The refrigeration apparatus of Patent Document 1 is installed in a convenience store or the like, and performs air conditioning in the store and cooling in the showcase, and includes an outdoor unit, an air conditioning unit, a refrigerated showcase, a refrigerated showcase, and a supercooling unit. And have.

  The outdoor unit has an outdoor circuit (heat source side circuit), the air conditioning unit has an air conditioning circuit (use side circuit), the refrigerated showcase has a refrigeration circuit (use side circuit), and the refrigeration showcase has a freezer. Each circuit (utilization side circuit) is provided, and an air conditioning circuit, a refrigeration circuit, and a refrigeration circuit are connected to the outdoor circuit in parallel through a liquid side and gas side communication pipe, so that a vapor compression refrigeration cycle is provided. The refrigerant circuit which performs is comprised.

  The supercooling unit is provided with a supercooling circuit connected to a supercooling heat exchanger to perform a vapor compression refrigeration cycle. Here, the supercooling heat exchanger has a high temperature side flow path and a low temperature side flow path, and the high temperature side flow path is connected to the liquid side communication pipe of the refrigerant circuit and the low temperature side flow A path is connected to the low pressure line of the supercooling circuit.

According to this configuration, when the compressor provided in the refrigerant circuit is started, the high-pressure refrigerant of the refrigerant circuit flows through the high-temperature side passage of the supercooling heat exchanger via the liquid side connection pipe. On the other hand, when the compressor provided in the supercooling circuit is started, the low-pressure refrigerant in the supercooling circuit flows through the low-temperature channel of the supercooling heat exchanger via the low-pressure line. In the supercooling heat exchanger, the high-pressure refrigerant in the refrigerant circuit flowing through the high-temperature side flow channel is radiated and cooled to the low-pressure refrigerant in the supercooling circuit flowing through the low-temperature side flow channel. This cooling increases the degree of supercooling of the high-pressure refrigerant in the refrigerant circuit, and improves the cooling capacity of the refrigeration apparatus.
Japanese Patent No. 3861912

  However, although the cooling capacity of the refrigeration apparatus can be improved by providing the supercooling unit, no consideration is given to the energy saving performance of the supercooling unit. As a result, it is considered that the energy saving performance of the entire refrigeration apparatus including the supercooling unit is reduced by the supercooling unit.

  The present invention has been made in view of such a point, and an object thereof is a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle and a supercooling circuit that supercools the refrigerant flowing through the refrigerant circuit. An object of the present invention is to improve the cooling capacity of the refrigeration apparatus while reducing the compression power of the supercooling compressor in the supercooling circuit.

  In the first aspect of the present invention, the utilization side circuit (50a, 60a, 70a) having the utilization side heat exchanger (52, 62, 72) is connected to the liquid side on the heat source side circuit (20a) having the compressor (21) for the heat source. Refrigerant circuit (1) connected with piping (80b, 80d, 80a, 80c) and gas side connecting piping (92, 95) to perform a vapor compression refrigeration cycle, supercooling compressor (11) and supercooling It is premised on a refrigeration apparatus including a supercooling circuit (10a) connected to an industrial expansion valve (EV1) and performing a vapor compression refrigeration cycle.

  The supercooling circuit (10a) of the refrigeration apparatus includes the intermediate pressure expansion valve (EV2) connected to the branch pipe (3a) branched from the high-pressure liquid line (3) of the supercooling circuit (10a) and the above-mentioned An intermediate pressure line (7b, 5) connecting the intermediate port provided to open to the compression chamber at the intermediate pressure position in the subcooling compressor (11), the first low temperature side flow path (14b) and the first The first high temperature side flow path (14a) is connected to the liquid side connection pipe (80b, 80d, 80a, 80c) and the first low temperature side flow path (14a) is provided. 14b) is a first subcooling heat exchanger (14) connected to the low pressure line (7a, 4) of the supercooling circuit (10a), a second low temperature side channel (15b), and a second high temperature side channel. (15a) and the second high temperature side channel (15a) is connected to the liquid side connecting pipe (80b, 80d, 80a, 80c) and the second low temperature side channel (15b) Cooling circuit (10a) During pressure line (7b, 5) connected to the to the second supercooling heat exchanger (15) and is characterized by being provided.

  Here, the refrigerant circuit (1) performing the vapor compression refrigeration cycle means that the refrigerant enclosed in the refrigerant circuit (1) circulates through the refrigerant circuit (1), the compression stroke, the condensation stroke, and the expansion stroke. It is possible to perform a cycle in which the evaporation process and the evaporation process are repeated in order, and include components that perform the above processes. In the refrigerant circuit (1) according to the first aspect of the present invention, the heat source compressor (21) is a component that performs the compression stroke of the refrigerant circuit (1), and the use side heat exchanger (52, 62, 72) Is a component that performs the condensation process or the evaporation process of the refrigerant circuit (1).

  The supercooling circuit (10a) for performing the vapor compression refrigeration cycle is similar to the refrigerant circuit (1) in that the refrigerant sealed in the supercooling circuit (10a) is the supercooling circuit (10a). It is possible to perform a cycle in which a compression stroke, a condensation stroke, an expansion stroke, and an evaporation stroke are repeated in order while circulating, and include components that perform the respective strokes. In the supercooling circuit (10a) of the first invention, the supercooling compressor (11) is a component for performing a compression stroke, and the supercooling expansion valve (EV1) and the intermediate pressure expansion valve (EV2) It is a component that performs the expansion stroke.

  The high-pressure liquid line (3) of the supercooling circuit (10a) flows through the high-pressure refrigerant that has condensed into a liquid phase or a two-phase state during the condensation process of the refrigeration cycle performed by the supercooling circuit (10a). It is refrigerant piping. The low pressure line (7a, 4) of the supercooling circuit (10a) is a refrigerant pipe through which low pressure refrigerant flows after being expanded by the supercooling expansion valve (EV1) of the supercooling circuit (10a). is there. The intermediate pressure line (7b, 5) is a refrigerant pipe through which the intermediate pressure refrigerant flows after being expanded by the intermediate pressure expansion valve (EV2).

  In the first invention, in the supercooling circuit (10a), part of the high-pressure refrigerant flowing through the high-pressure liquid line (3) expands to become low-pressure refrigerant and flows into the low-pressure line (7a, 4). The remainder flows into the intermediate pressure expansion valve (EV2) through the branch pipe (3a), and then expands in the intermediate pressure expansion valve (EV2) to become intermediate pressure refrigerant and flows into the intermediate pressure line (7b, 5). .

  The low-pressure refrigerant that has flowed into the low-pressure line (7a, 4) passes through the first low-temperature channel (14b) of the first subcooling heat exchanger (14) connected to the low-pressure line (7a, 4). At this time, the refrigerant absorbs heat from the high-pressure refrigerant flowing through the first high temperature side flow path (14a) of the first subcooling heat exchanger (14) and evaporates. On the other hand, the intermediate-pressure refrigerant that has flowed into the intermediate pressure line (7b, 5) passes through the second low-temperature side flow path (2) of the second supercooling heat exchanger (15) connected to the intermediate pressure line (7b, 5). When passing through 15b), it evaporates by absorbing heat from the high-pressure refrigerant flowing through the second high-temperature side flow path (15a) of the second subcooling heat exchanger (15).

  The low-pressure refrigerant evaporated in the first supercooling heat exchanger (14) is drawn into the compression chamber at the suction pressure position from the suction port of the supercooling compressor (11). Then, when the compression chamber of the supercooling compressor (11) reaches an intermediate pressure position in the middle of changing from the suction pressure position to the discharge pressure position, the intermediate pressure evaporated by the second supercooling heat exchanger (15). The refrigerant is injected into the compression chamber at the intermediate pressure position. The injected intermediate pressure refrigerant merges with the low-pressure refrigerant compressed halfway, and then is compressed to a predetermined pressure to become a high-pressure refrigerant, which is discharged from the supercooling compressor (11).

  On the other hand, in the refrigerant circuit (1), the high-pressure refrigerant flowing out from the heat source side circuit (20a) flows into the liquid side connection pipes (80b, 80d, 80a, 80c). The high-pressure refrigerant that has flowed into the liquid side communication pipe (80b, 80d, 80a, 80c) flows through the first subcooling heat exchanger (14) connected to the liquid side communication pipe (80b, 80d, 80a, 80c). When passing through the first high-temperature channel (14a), cooling is performed with the low-pressure refrigerant of the supercooling circuit (10a) flowing through the first low-temperature channel (14b) of the first supercooling heat exchanger (14). Is done. The high-pressure refrigerant that has flowed into the liquid side connecting pipe (80b, 80d, 80a, 80c) is connected to the liquid side connecting pipe (80b, 80d, 80a, 80c). ) Of the supercooling circuit (10a) flowing through the second low temperature side channel (15b) of the second supercooling heat exchanger (15) when passing through the second high temperature side channel (15a). Cooled with refrigerant.

  As described above, in the supercooling compressor (11), the low pressure refrigerant sucked from the low pressure line (7a, 4) is not compressed as it is, but in the middle of the compression, the intermediate port is placed in the compression chamber at the intermediate pressure position. The intermediate-pressure refrigerant sucked from the can be injected. Further, the intermediate pressure refrigerant decompressed by the intermediate pressure expansion valve (EV2) is not directly injected into the compression chamber at the intermediate pressure position, but the second subcooling heat exchanger (15) does not inject the liquid side communication pipe (80b , 80d, 80a, 80c). As a result, the high-pressure refrigerant in the liquid side connecting pipe (80b, 80d, 80a, 80c) can be heat-exchanged by both the first and second subcooling heat exchangers (14, 15).

  According to a second invention, in the first invention, the use side circuit (50a, 60a, 70a) and a first use side circuit (60a, 70a) arranged in parallel with the heat source side circuit (20a) The first liquid side connecting pipe (80b, 80d) as the liquid side connecting pipe having the two use side circuits (50a) and connecting the heat source side circuit (20a) and the first use side circuit (60a, 70a). ) Is connected to the first high temperature side flow path (14a) of the first subcooling heat exchanger (14), and connects the heat source side circuit (20a) and the second usage side circuit (50a). The second liquid side connecting pipe (80a, 80c) as the side connecting pipe is connected to the second high temperature side channel (15a) of the second subcooling heat exchanger (15). .

  In the second invention, a part of the high-pressure refrigerant flowing out from the heat source side circuit (20a) flows to the first liquid side connecting pipe (80b, 80d), and the rest is the second liquid side connecting pipe (80a, To 80c).

  Then, the high-pressure refrigerant that has flowed to the first liquid side connection pipe (80b, 80d) is supplied to the first subcooling heat exchanger (14) connected to the first liquid side connection pipe (80b, 80d). When passing through the high temperature side flow path (14a), the low pressure refrigerant flows through the first low temperature side flow path (14b) of the first supercooling heat exchanger (14). On the other hand, when the high-pressure refrigerant that has flowed into the second liquid side connecting pipe (80a, 80c) passes through the second high temperature side flow path (15a) of the second subcooling heat exchanger (15), 2 Cooled by the intermediate pressure refrigerant flowing through the second low-temperature channel (15b) of the supercooling heat exchanger (15).

  In this way, the high-pressure refrigerant flowing through the liquid side connecting pipes (80b, 80d, 80a, 80c) can be cooled by the separate supercooling heat exchangers (14, 15).

  According to a third invention, in the second invention, the use side heat exchanger of the first use side circuit (60a, 70a) is composed of a cooling heat exchanger (62, 72) for cooling the interior, The utilization side heat exchanger of the second utilization side circuit (50a) is characterized by comprising an air conditioning heat exchanger (52) for air conditioning the room.

  In the third invention, the high-pressure refrigerant cooled by the low-pressure refrigerant of the supercooling circuit (10a) in the first supercooling heat exchanger (14) is provided in the first usage side circuit (60a, 70a). After expansion by the expansion valve, heat can be exchanged with the internal air in the cooling heat exchanger (62, 72). The high-pressure refrigerant cooled by the intermediate-pressure refrigerant in the supercooling circuit (10a) in the second supercooling heat exchanger (15) is expanded by the expansion valve provided in the second use side circuit (50a). Thereafter, heat can be exchanged with room air in the air conditioner heat exchanger (52).

  Here, in general, in the supercooling heat exchanger, the heat exchange amount of the supercooling heat exchanger increases as the evaporation temperature of the refrigerant flowing through the low temperature side flow path decreases. Therefore, when the first and second subcooling heat exchangers (14, 15) are compared, the first subcooling heat exchanger (14) through which the low-pressure refrigerant flows is the second subcooling through which the intermediate-pressure refrigerant flows. The amount of heat exchange tends to be larger than that of the heat exchanger (15). That is, the degree of supercooling of the high-pressure refrigerant cooled by the first subcooling heat exchanger (14) is likely to be larger than that of the high-pressure refrigerant cooled by the second subcooling heat exchanger (15).

  On the other hand, when comparing the heat exchanger for cooling (62,72) that cools the interior with the heat exchanger for air conditioning (52) that air-conditions the room, the heat exchange of the heat exchanger for cooling (62,72) The amount needs to be set more.

  Therefore, in the third aspect of the invention, the high-pressure refrigerant having a high degree of supercooling is sent to the cooling heat exchanger (62, 72) of the first use side circuit (60a, 70a), and the high-pressure refrigerant having a low degree of supercooling. Can be sent to the heat exchanger (52) for air conditioning of the second usage side circuit (50a).

  According to a fourth invention, in the second or third invention, the third low temperature side flow path (16b) includes the third low temperature side flow path (16b) and the third high temperature side flow path (16a). The third high temperature side flow path (16a) is connected to the low pressure line (7a, 4) of the supercooling circuit (10a) and the second high temperature side flow path (15a) of the second supercooling heat exchanger (15). ), The third subcooling heat exchanger (16) connected to the second liquid side connecting pipe (80a, 80c) so as to be located on the second usage side circuit (50a) side. It is said.

  In the fourth invention, the high pressure refrigerant flowing through the second liquid side connecting pipe (80a, 80c) is connected to the second liquid side connecting pipe (80a, 80c). ) Is cooled by the intermediate pressure refrigerant flowing through the second low temperature side channel (15b) of the second supercooling heat exchanger (15). Then, the high-pressure refrigerant cooled by the second supercooling heat exchanger (15) flows into the third high-temperature side flow path (16a) of the third supercooling heat exchanger (16) and enters the third high-temperature refrigerant. When passing through the side flow path (16a), it is cooled by the low-pressure refrigerant flowing through the third low temperature side flow path (16b) of the third supercooling heat exchanger (16).

  Thus, the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) can be cooled by both the low-pressure refrigerant and the intermediate-pressure refrigerant in the supercooling circuit (10a).

  In a fifth aspect based on the fourth aspect, the second liquid side connecting pipe (80a, 80c) bypasses the third high temperature side flow path (16a) of the third subcooling heat exchanger (16). And a first opening / closing valve (82) for opening and closing the bypass passage (81).

  In the fifth invention, when the first on-off valve (82) is opened, the bypass flow path (81) is opened, and the high-pressure refrigerant cooled by the second supercooling heat exchanger (15) is transferred to the bypass flow path ( After passing through 81), the flow flows to the second utilization side circuit (50a). On the other hand, when the first on-off valve (82) is closed, the bypass flow path (81) is closed, and the high-pressure refrigerant cooled by the second subcooling heat exchanger (15) is converted into the third subcooling heat exchanger. It flows to the third high temperature side channel (16a) of (16). Then, after passing through the third high temperature side channel (16a), after being cooled by the low pressure refrigerant flowing through the third low temperature side channel (16b) of the third supercooling heat exchanger (16), It flows to the second usage side circuit (50a).

  Thus, by the opening / closing operation of the first on-off valve (82), the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) is supplied to the second and third supercooling heat exchangers (15, 16). Both or only the second subcooling heat exchanger (15) can be selectively cooled.

  According to a sixth invention, in any one of the second to fifth inventions, the fourth low temperature side flow path (91b) and the fourth high temperature side flow path (91a) have the fourth low temperature side flow path (91a). 91b) is connected to the intermediate pressure line (7b, 5) of the supercooling circuit (10a) and the fourth high temperature side channel (91a) is the first high temperature side of the first supercooling heat exchanger (14). A fourth subcooling heat exchanger (91) connected to the first liquid side connecting pipe (80b, 80d) so as to be positioned closer to the heat source side circuit (20a) than the flow path (14a); It is characterized by.

  In the sixth invention, the high pressure refrigerant flowing through the first liquid side connection pipe (80b, 80d) is connected to the first liquid side connection pipe (80b, 80d). ), The refrigerant is cooled by the intermediate pressure refrigerant flowing through the fourth low temperature side channel (91b) of the fourth supercooling heat exchanger (91). Then, the high-pressure refrigerant cooled by the fourth supercooling heat exchanger (91) flows into the first high-temperature side flow path (14a) of the first supercooling heat exchanger (14) and enters the first high-temperature refrigerant. When passing through the side flow path (14a), it is cooled by the low-pressure refrigerant flowing through the first low-temperature side flow path (14b) of the first supercooling heat exchanger (14).

  Thus, the high-pressure refrigerant in the first liquid side connecting pipe (80b, 80d) can be cooled by both the first and fourth subcooling heat exchangers (91).

  In a seventh aspect based on the first aspect, the first high temperature side flow path (14a) of the first subcooling heat exchanger (14) is a second high temperature of the second subcooling heat exchanger (15). It is characterized by being connected to the liquid side connecting pipe (80b, 80d, 80a, 80c) so as to be located on the use side circuit (50a, 60a, 70a) side with respect to the side flow path (15a).

  In the seventh invention, the high-pressure refrigerant flowing out of the heat source side circuit (20a) and flowing through the liquid side connecting pipe (80b, 80d, 80a, 80c) is transferred to the liquid side connecting pipe (80b, 80d, 80a, 80c). When passing through the second high temperature side channel (15a) of the second subcooling heat exchanger (15) connected to the second subcooling heat exchanger (15), the second low temperature side channel ( Cooled with intermediate pressure refrigerant flowing through 15b). Then, the high-pressure refrigerant cooled by the second supercooling heat exchanger (15) flows into the first high-temperature side flow path (14a) of the first supercooling heat exchanger (14) and enters the first high-temperature refrigerant. When passing through the side flow path (14a), it is cooled by the low-pressure refrigerant flowing through the first low-temperature side flow path (14b) of the first supercooling heat exchanger (14).

  Thus, after the high pressure refrigerant in the liquid side connecting pipe (80b, 80d, 80a, 80c) is cooled by the intermediate pressure refrigerant of the second supercooling heat exchanger (15), the evaporation temperature is higher than that of the intermediate pressure refrigerant. It becomes possible to further cool with the low-pressure refrigerant of the first supercooling heat exchanger (14) having a low temperature.

  According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the communication path connecting the intermediate pressure line (7b, 5) and the low pressure line (7a, 4) of the supercooling circuit (10a) ( 6) is characterized in that a second on-off valve (SV2) for opening and closing the communication passage (6) is provided.

  In the eighth invention, when the second on-off valve (SV2) is opened, the communication passage (6) is opened. Then, a part of the intermediate pressure refrigerant flowing through the intermediate pressure line (7b, 5) joins with the low pressure refrigerant flowing through the low pressure line (7a, 4) via the communication path (6). Then, the merged refrigerant is sucked into the suction port of the supercooling compressor (11). On the other hand, when the second on-off valve (SV2) is closed, the communication path (6) is closed. Then, the intermediate pressure refrigerant flowing through the intermediate pressure line (7b, 5) does not merge with the low pressure refrigerant flowing through the low pressure line (7a, 4). Therefore, the low-pressure refrigerant flowing through the low-pressure line (7a, 4) is directly sucked into the suction port of the supercooling compressor (11).

  Thus, the intermediate pressure refrigerant can be merged with the low pressure refrigerant as required by the second on-off valve (SV2).

  According to the present invention, in the supercooling compressor (11), the low-pressure refrigerant sucked from the low-pressure line (7a, 4) is not compressed as it is, but is compressed in the compression chamber at the intermediate pressure position in the middle of the compression. The intermediate pressure refrigerant sucked from the intermediate pressure line (7b, 5) can be injected. As a result, the temperature of the high-pressure refrigerant discharged from the supercooling compressor (11) can be lowered compared with the case where the intermediate pressure refrigerant is not sucked, and the compression power in the supercooling compressor (11) can be reduced. Can be reduced.

  Further, the intermediate pressure refrigerant decompressed by the intermediate pressure expansion valve (EV2) is not directly injected into the compression chamber at the intermediate pressure position, but the second subcooling heat exchanger (15) Heat exchange can be performed with the high-pressure refrigerant in the liquid side connection pipe (80b, 80d, 80a, 80c). Thereby, compared with the case where intermediate pressure refrigerant is directly injected into the compression chamber, the high pressure refrigerant in the liquid side connecting pipes (80b, 80d, 80a, 80c) is supplied to the first and second subcooling heat exchangers (14, 15). ) And the degree of supercooling of the high-pressure refrigerant can be increased as compared with the case of cooling only with the first subcooling heat exchanger (14).

  As described above, the refrigeration apparatus of the present invention reduces the compression power of the supercooling compressor (11) of the supercooling circuit (10a) and flows through the liquid side connecting pipes (80b, 80d, 80a, 80c). The cooling capacity of the refrigeration apparatus can be improved by increasing the degree of supercooling of the high-pressure refrigerant.

  Further, according to the second aspect of the invention, unlike the conventional supercooling circuit, the high-pressure refrigerant flowing through the liquid side connecting pipes (80b, 80d, 80a, 80c) is separated into separate supercooling heat exchangers (14 15). That is, since only one supercooling heat exchanger is connected to the conventional supercooling circuit, the use side circuit (50a, 60a, 70a) is arranged in parallel with the heat source side circuit (20a). In the case of having one usage side circuit (60a, 70a) and second usage side circuit (50a), the degree of supercooling of the high-pressure refrigerant flowing to each usage side circuit (50a, 60a, 70a) It was not possible to adjust for each use side circuit (50a, 60a, 70a).

  However, in the second invention, as described above, the high-pressure refrigerant flowing through the liquid side connecting pipes (80b, 80d, 80a, 80c) is cooled by separate supercooling heat exchangers (14, 15). Therefore, it is possible to adjust the degree of supercooling of the high-pressure refrigerant flowing to each usage side circuit (50a, 60a, 70a) for each usage side circuit (50a, 60a, 70a).

  According to the third invention, after the high pressure refrigerant having a relatively high degree of supercooling is expanded by being cooled by the first supercooling heat exchanger (14), the high pressure refrigerant and the internal air are Heat can be exchanged with the cooling heat exchanger (62, 72). In addition, after the high-pressure refrigerant cooled by the second supercooling heat exchanger (15) and having a relatively small degree of supercooling is expanded, the high-pressure refrigerant and room air are transferred to the air conditioning heat exchanger (52 ) For heat exchange.

  Thereby, the heat exchange amount of the cooling heat exchanger (62, 72) can be set larger than that of the air conditioning heat exchanger (52).

  According to the fourth aspect of the invention, the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) can be cooled by both the low-pressure refrigerant and the intermediate-pressure refrigerant in the supercooling circuit (10a). Thereby, compared with the case where only the second subcooling heat exchanger (15) performs high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c), the second liquid side connecting pipe (80a, 80c) The degree of supercooling of the high-pressure refrigerant can be increased. The high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) is further cooled by the low-pressure refrigerant in the supercooling circuit (10a) after being cooled by the intermediate-pressure refrigerant in the supercooling circuit (10a). The As described above, the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) can be efficiently cooled stepwise in order from the higher one of the intermediate-pressure refrigerant and the low-pressure refrigerant.

  According to the fifth aspect of the present invention, the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) is transferred to the middle of the supercooling circuit (10a) by the opening / closing operation of the first on-off valve (82). It is possible to selectively cool with both the pressure refrigerant and the low pressure refrigerant, or only with the intermediate pressure refrigerant. From this, it becomes possible to easily change the cooling amount of the high-pressure refrigerant flowing through the second liquid side connecting pipe (80a, 80c) by the opening / closing operation of the first on-off valve (82).

  According to the sixth aspect of the present invention, the fourth supercooling heat exchanger (91) is provided, whereby the high pressure refrigerant in the first liquid side connecting pipe (80b, 80d) is supplied to the supercooling circuit (10a). ) Can be cooled with both a low-pressure refrigerant and an intermediate-pressure refrigerant. As a result, the first liquid side connecting pipe (80b, 80d) can be compared with the case where the first liquid side connecting pipe (80b, 80d) is used as a high-pressure refrigerant only by the first subcooling heat exchanger (14). The degree of supercooling of the high-pressure refrigerant can be increased. The high pressure refrigerant in the first liquid side connecting pipe (80b, 80d) is further cooled by the low pressure refrigerant in the supercooling circuit (10a) after being cooled by the intermediate pressure refrigerant in the supercooling circuit (10a). The As described above, the high-pressure refrigerant in the first liquid side connecting pipe (80b, 80d) can be efficiently cooled stepwise in order from the higher one of the intermediate-pressure refrigerant and the low-pressure refrigerant.

  Further, according to the seventh invention, the high-pressure refrigerant flowing through the liquid side connection pipes (80b, 80d, 80a, 80c) is cooled by the low-pressure refrigerant of the first supercooling heat exchanger (14). After that, if it is cooled with the intermediate pressure refrigerant of the second subcooling heat exchanger (15), if the amount of heat exchange in the first subcooling heat exchanger (14) is too large, the first subcooling may be caused in some cases. The outlet temperature of the high-pressure refrigerant that has flowed out of the first high-temperature channel (14a) of the heat exchanger (14) may be lower than the evaporation temperature of the intermediate-pressure refrigerant. Then, the high pressure refrigerant is not cooled by the second subcooling heat exchanger (15).

  However, according to the seventh invention, after the high-pressure refrigerant in the liquid side connecting pipe (80b, 80d, 80a, 80c) is cooled with the intermediate-pressure refrigerant in the second subcooling heat exchanger (15), the first Since it cools with the low pressure refrigerant | coolant of a supercooling heat exchanger (14), this high pressure refrigerant | coolant does not stop being cooled with a 2nd supercooling heat exchanger (15). Therefore, the high-pressure refrigerant in the liquid side connecting pipe (80b, 80d, 80a, 80c) can be efficiently cooled.

  According to the eighth invention, for example, when the pressure of the low-pressure refrigerant flowing through the low-pressure line (7a, 4) of the supercooling circuit (10a) becomes too low, the second on-off valve (SV2) is opened. The pressure of the low-pressure refrigerant flowing through the low-pressure line (7a, 4) by flowing the intermediate-pressure refrigerant of the supercooling circuit (10a) from the intermediate pressure line (7b, 5) into the low-pressure line (7a, 4) Can be high. As a result, the suction pressure of the supercooling compressor (11) can be prevented from becoming too low. For example, the supercooling compressor (11) is forcibly stopped due to a decrease in the suction pressure. Can be prevented.

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

Embodiment 1
As shown in FIG. 1, the refrigeration apparatus of Embodiment 1 includes an outdoor unit (20), an indoor unit (50), a refrigerated showcase (60), a refrigeration showcase (70), a supercooling unit ( And 10). The outdoor unit (20) is provided with an outdoor circuit (20a). The indoor unit (50) is provided with an indoor circuit (50a). The refrigerated showcase (60) is provided with a refrigerated circuit (60a). The refrigeration showcase (70) is provided with a refrigeration circuit (70a). The supercooling unit (10) is provided with a supercooling circuit (10a). Details of the supercooling circuit (10a) are shown in FIG. Here, the outdoor circuit (20a) constitutes a heat source side circuit, the indoor circuit (50a) constitutes a second usage side circuit, and the refrigeration circuit (60a) and the refrigeration circuit (70a) constitute a first usage side. Configure the circuit.

  In this refrigeration apparatus, each circuit (10a, 20a, 50a, 60a, 70a) is connected by a communication pipe, whereby a refrigerant circuit (1) that performs a vapor compression refrigeration cycle is configured. The connecting pipe is composed of first and second liquid side connecting pipes (80a, 80c, 80b, 80d) and first and second gas side connecting pipes (92, 95). The first liquid side connecting pipe (80b, 80d) has a first pipe (80b) and a second pipe (80d), and the second liquid side connecting pipe (80a, 80c) is a first pipe (80b, 80d). 80a) and a second tube (80c).

  In the first liquid side connecting pipe (80b, 80d), the first pipe (80b) is connected to the second liquid side shut-off valve (43d) of the outdoor circuit (20a) and the second end of the supercooling circuit (10a). (18b) and the second pipe (80d) is connected to the fourth end (18d) of the supercooling circuit (10a), the liquid end (65) of the refrigeration circuit (60a), and the refrigeration circuit (70a). This is connected to the refrigeration liquid side stop valve (85).

  In the second liquid side connecting pipe (80a, 80c), the first pipe (80a) is connected to the first liquid side shut-off valve (43c) of the outdoor circuit (20a) and the first end of the supercooling circuit (10a). (18a) is connected, and the second pipe (80c) connects the third end (18c) of the supercooling circuit (10a) and the liquid end (56) of the outdoor circuit (20a).

  The first gas side communication pipe (92) connects the first gas side closing valve (43a) of the outdoor circuit (20a) and the gas end (55) of the indoor circuit (50a).

  The second gas side communication pipe (95) includes a second gas side stop valve (43b) of the outdoor circuit (20a), a gas end (66) of the refrigeration circuit (60a), and a refrigeration of the refrigeration circuit (70a). The gas side shut-off valve (84) is connected.

  Further, a pipe branched from the supercooling circuit (10a) to the refrigeration circuit (60a) side in the second pipe (80d) of the first liquid side connecting pipe (80b, 80d), and the second gas side connecting pipe There is provided a bypass pipe (94) for connecting piping connecting the piping branched from the outdoor circuit (20a) to the refrigeration circuit (60a) side in (95). The communication pipe bypass pipe (94) is for preventing liquid sealing of the refrigeration circuit (60a). The communication pipe bypass pipe (94) includes the first liquid side connection pipe (80b, A check valve (CV20) is provided in such a direction as to permit only the refrigerant flow from the second pipe (80d) of 80d) toward the second gas side communication pipe (95).

<Outdoor unit>
The outdoor circuit (20a) of the outdoor unit (20) includes a compression mechanism (heat source compressor) (21) including three compressors (21a, 21b, 21c) from first to third, 1 to 3 four-way selector valves (26a, 26b, 26c), outdoor heat exchanger (22), receiver (23), first and second outdoor supercooling heat exchangers (24, 25) An outdoor supercooling pressure reducing valve (EV7) and an outdoor expansion valve (EV6) are provided.

  All the compressors (21a, 21b, 21c) are all hermetic high-pressure dome type scroll compressors, and each of the compressors (21a, 21b, 21c) has a compression chamber at an intermediate pressure position. An intermediate port is provided so as to open.

  The electric motor of the first compressor (21a) is connected to an inverter that can freely change the rotation speed of the electric motor within a predetermined range. The operating capacity of the first compressor (21a) can be increased or decreased by adjusting the rotational speed of the electric motor with this inverter. The electric motors of the second and third compressors (21b, 21c) are not provided with an inverter, and the rotational speed of the electric motor is fixed. Therefore, the operating capacity of the above-mentioned 2, 3 compressors (21b, 21c) is constant.

  Discharge pipes (30a, 30b, 30c) are connected to the discharge side of the compressors (21a, 21b, 21c). These discharge pipes (30a, 30b, 30c) join at one end of the discharge junction pipe (31). The other end of the discharge junction pipe (31) is connected to a first port of a first four-way switching valve (26a) described later.

  An oil separator (49a, 49b, 49c) is connected to each discharge pipe (30a, 30b, 30c). The oil separators (49a, 49b, 49c) are for separating the refrigerating machine oil from the high-pressure refrigerant discharged from the compressors (21a, 21b, 21c). Each oil separator (49a, 49b, 49c) is connected to an oil outflow pipe (47a, 47b, 47c) for flowing out refrigeration oil. These oil outflow pipes (47a, 47b, 47c) join at one end of the oil outflow joining pipe (44). The other end of the oil outflow merging pipe (44) is connected to an injection pipe (28) described later. The oil separator (49a, 49b, 49c), the oil outflow pipe (47a, 47b, 47c), and the oil outflow merging pipe (44) constitute an oil return circuit.

  The oil spill pipes (47a, 47b, 47c) and check valves (CV5, CV6, CV7) and capillaries in order from the oil separators (49a, 49b, 49c) to the oil spill confluence pipe (44) Tubes (48a, 48b, 48c) are provided. Here, each check valve (CV5, CV6, CV7) is provided in such a direction as to allow only the flow of the refrigerating machine oil from the oil separator (49a, 49b, 49c) to the oil outflow merging pipe (44). ing.

  Suction pipes (40a, 40b, 40c) are connected to the suction sides of the first to third compressors (21a, 21b, 21c). The end portion of the suction pipe (40a) connected to the first compressor (21a) branches, one is connected to the fourth port of the third four-way selector valve (26c), and the other is the second gas. It is connected to the side closing valve (43b). The end of the suction pipe (40b) connected to the second compressor (21b) is connected to the second port of the third four-way switching valve (26c). Further, the end of the suction pipe (40c) connected to the third compressor (21c) is branched, and one end of the third four-way switching valve (26c) is third through the check valve (CV18). The other is connected to the second port of the second four-way selector valve (26b).

  The first four-way selector valve (26a) has a second port at the fourth port of the second four-way selector valve (26b), a third port at the one end side of the outdoor heat exchanger (22), The ports are respectively connected to the first gas side closing valves (43a). The first port of the first four-way selector valve (26a) is connected to the discharge junction pipe (31) as described above.

  The second four-way switching valve (26b) has a first port closed by a discharge junction pipe (31) and a third port closed. The second port of the second four-way selector valve (26b) is connected to the third suction pipe (40c) as described above, and the fourth port of the second four-way selector valve (26b) is as described above. Is connected to the second port of the first four-way selector valve (26a).

  In the third four-way selector valve (26c), the first port is connected to the discharge junction pipe (31) via the second refrigerant pipe (42), and the second port is the second suction pipe (26c) as described above. 40b), the third port is connected to the third suction pipe (40c) as described above, and the fourth port is connected to the first suction pipe (40a) as described above.

  Each of the four-way switching valves (26a, 26b, 26c) is in a first state (shown 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. State) and a second state (state indicated by a broken line in FIG. 1) in which the first port and the fourth port communicate with each other and the second port and the third port communicate with each other.

  The outdoor heat exchanger (22) is a cross-fin type fin-and-tube heat exchanger. An outdoor fan (27) is provided in the vicinity of the outdoor heat exchanger (22). The outdoor heat exchanger (22) is configured to exchange heat between outdoor air sent by the outdoor fan (27) and the refrigerant flowing in the outdoor heat exchanger (22). As described above, one end of the outdoor heat exchanger (22) is connected to the third port of the first four-way selector valve (26a), and the other refrigerant coolant pipe (32) is connected to the other end. The end of the third refrigerant pipe (32) is connected to the top of the receiver (23).

  The third refrigerant pipe (32) is provided with a check valve (CV9) and a solenoid valve (SV1). The check valve (CV9) is connected to the receiver (22) from the outdoor heat exchanger (22). It is installed in a direction that allows only the flow of refrigerant toward 23). The outdoor circuit (20a) is provided with a first bypass pipe (39) that bypasses the check valve (CV9) and the solenoid valve (SV1) of the third refrigerant pipe (32). A check valve (CV8) is attached to the first bypass pipe (39) in such a direction as to permit only the flow of refrigerant from the receiver (23) toward the outdoor heat exchanger (22).

  The receiver (23) can temporarily store the high-pressure refrigerant condensed in the outdoor heat exchanger (22). One end of a gas vent pipe (27) having a solenoid valve (SV0) is connected to the top of the receiver (23). The other end of the gas vent pipe (27) is connected in the middle of an injection pipe (28) described later.

  The first outdoor subcooling heat exchanger (24) has a high temperature side channel (24a) and a low temperature side channel (24b), and the high temperature side channel (24a) and the low temperature side channel ( The refrigerant flowing through 24b) is configured to exchange heat. The second outdoor subcooling heat exchanger (25) is similar to the first outdoor subcooling heat exchanger (24) in that the high temperature side channel (not shown) and the low temperature side channel (not shown). The refrigerant flowing through the high temperature side flow path and the low temperature side flow path is configured to exchange heat.

  The fourth refrigerant pipe (34) extending from the bottom of the receiver (23) has an end branched, and one of the fourth refrigerant pipe (34) flows into the high temperature side flow path (24a) in the first outdoor subcooling heat exchanger (24). The other end is connected to the inflow end of the high-temperature channel in the second outdoor subcooling heat exchanger (25). In addition, the outdoor circuit (20a) is connected to the outflow end of the high temperature side passage (24a) and the second liquid side shut-off valve (43d) in the first outdoor subcooling heat exchanger (24). A sixth refrigerant pipe (36) connecting the five refrigerant pipes (35) to the outflow end of the high-temperature side flow path and the first liquid side shut-off valve (43c) in the second outdoor supercooling heat exchanger (25). And are provided.

  The sixth refrigerant pipe (36) is provided with a check valve (CV11), and the check valve (CV11) is connected to the first liquid side from the second outdoor supercooling heat exchanger (25). It is provided in a direction that allows only the flow of the refrigerant toward the closing valve (43c).

  In addition, the outdoor circuit (20a) extends from between the first liquid side shut-off valve (43c) and the check valve (CV11) in the sixth refrigerant pipe (36) to the third refrigerant pipe (32). A seventh refrigerant pipe (37) connected between the receiver (23) and the check valve (CV9) is provided. The seventh refrigerant pipe (37) is provided with a check valve (CV12) in a direction allowing the refrigerant flow from the sixth refrigerant pipe (36) to the third refrigerant pipe (32).

  The outdoor circuit (20a) extends from between the outdoor heat exchanger (22) and the solenoid valve (SV1) in the third refrigerant pipe (32) and extends in the fifth refrigerant pipe (35). An eighth refrigerant pipe (33) connected between the one outdoor supercooling heat exchanger (24) and the second liquid side shut-off valve (43d) is provided. The eighth refrigerant pipe (33) is provided with the outdoor expansion valve (EV6) and the check valve (CV19) in order from the third refrigerant pipe (32) to the fifth refrigerant pipe (35). It has been. The check valve (CV19) is attached in such a direction as to allow only the flow of the refrigerant from the fifth refrigerant pipe (35) to the eighth refrigerant pipe (33). The outdoor expansion valve (EV6) is constituted by an electrically operated valve having a variable opening.

  Further, the outdoor circuit (20a) includes the receiver in the third refrigerant pipe (32) extending from between the outdoor expansion valve (EV6) and the check valve (CV19) in the eighth refrigerant pipe (33). A ninth refrigerant pipe (38) connected between (23) and the check valve (CV9) is provided. A check valve (CV10) is connected to the ninth refrigerant pipe (38) in such a direction as to allow only a flow from the eighth refrigerant pipe (33) to the third refrigerant pipe (32).

  An inlet end of an injection pipe (28) is connected between the first outdoor subcooling heat exchanger (24) and the second liquid side shut-off valve (43d) in the fifth refrigerant pipe (35). . And the exit end of the said injection piping (28) branches into three, The branch end is connected to the intermediate | middle port of each compressor (21a, 21b, 21c).

  Here, between the inlet end and the branch portion in the injection pipe (28), the outdoor supercooling pressure reducing valve (EV7) and the second outdoor subcooling are sequentially arranged from the inlet end toward the branch portion. The low temperature side flow path of the heat exchanger (25) and the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24) are connected. In addition, a flow rate adjusting valve (EV3, EV4, EV5) is provided between the branch portion and each branch end in the injection pipe (28). The flow rate adjusting valves (EV3, EV4, EV5) and the outdoor supercooling pressure reducing valve (EV7) are each constituted by a motor valve having a variable opening.

  Various sensors and pressure switches are provided in the outdoor circuit (20a). Specifically, each discharge pipe (30a, 30b, 30c) is provided with a discharge pipe temperature sensor (106, 107, 108) and a high pressure switch (132, 128, 129), respectively. Each discharge pipe temperature sensor (106, 107, 108) detects the temperature of the discharge pipe (30a, 30b, 30c), and the high-pressure switch (132, 128, 129) detects the discharge pressure and emergency stops the refrigeration system at abnormally high pressure It is.

  The branch pipe (40d) and the third suction pipe (40c) of the first suction pipe (40a) are provided with first and second suction pipe temperature sensors (115, 116), respectively. In the vicinity of the outdoor fan (27), an outside air temperature sensor (110) for detecting the outside air temperature is provided. An injection temperature sensor (112) is provided in the vicinity of the outflow end of the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24) in the injection pipe (28).

  Discharge pressure sensor for detecting the discharge pressure of the compressor (21a, 21b, 21c) at the confluence of the discharge pipes (30a, 30b, 30c) (that is, the inflow end of the discharge confluence pipe (31)) (109) is provided. A branch pipe (40d) of the first suction pipe (40a) is provided with a first suction pressure sensor (114) for detecting the suction pressure of the refrigerant. The third suction pipe (40c) is provided with a second suction pressure sensor (116) for detecting the suction pressure of the refrigerant. The injection pipe (28) has an injection pressure sensor (113) for detecting the pressure between the outdoor supercooling pressure reducing valve (EV7) and the flow rate adjusting valves (EV3, EV4, EV5). Is provided.

<Indoor unit>
The indoor heat exchanger (air conditioner heat exchanger) (52) and the indoor expansion valve (EV8) are arranged in order from the gas end (55) to the liquid end (56) of the indoor circuit (50a) in the indoor unit (50). Is provided. The indoor heat exchanger (52) is a cross fin type fin-and-tube heat exchanger. In this indoor heat exchanger (52), the indoor heat exchanger (52) is composed of a refrigerant flowing through the indoor heat exchanger (52) and an indoor fan (54) provided in the vicinity of the indoor heat exchanger (52). Heat is exchanged with the room air blown to the room, and the room air is cooled.

  The indoor expansion valve (EV8) is an electric expansion valve whose opening degree can be adjusted, and a first indoor refrigerant temperature sensor (118) provided near the gas end (55) of the indoor circuit (50a). ) Of the indoor expansion valve (EV8) is adjusted in accordance with the detected temperature. In addition, a second indoor refrigerant temperature sensor (120) is provided in the heat transfer pipe near the liquid end (56) in the indoor heat exchanger (52), and in the vicinity of the indoor heat exchanger (52) An indoor temperature sensor (119) for detecting the temperature of the air is provided.

<Refrigerated showcase>
The refrigeration expansion valve (EV9) and the refrigeration heat exchanger (cooling heat exchanger) in order from the liquid end (65) to the gas end (66) of the refrigeration circuit (60a) in the refrigerated showcase (60) ( 62) is provided. The refrigeration heat exchanger (62) is a cross-fin type fin-and-tube heat exchanger. In the refrigeration heat exchanger (62), the refrigeration heat is supplied from the refrigerant flowing through the refrigeration heat exchanger (62) and the refrigeration fan (64) provided in the vicinity of the refrigeration heat exchanger (62). Heat exchange is performed with the air in the refrigerated showcase (60) blown to the exchanger (62), and the air in the refrigerated showcase (60) is cooled.

  The refrigeration expansion valve (EV9) is a temperature-sensitive expansion valve, and the refrigeration expansion valve (EV9) is connected to the heat transfer pipe near the gas end (66) in the refrigeration heat exchanger (62). The temperature sensing cylinder (121) is connected. Further, in the vicinity of the refrigeration heat exchanger (62), a refrigeration inside temperature sensor (122) for detecting the temperature of air in the refrigerator is provided.

<Frozen showcase>
The refrigeration circuit (70a) of the refrigeration showcase (70) includes a refrigeration supercooling heat exchanger (73), a refrigeration heat exchanger (cooling heat exchanger) (72), a booster compressor (71), A refrigeration expansion valve (EV10) and first and second refrigeration decompression valves (EV11, EV12) are provided.

  The end of the first refrigeration refrigerant pipe (78) connected to the refrigeration liquid side stop valve (85) of the refrigeration circuit (70a) has first to fourth branch ends.

  The first branch end is connected to an inlet of a high temperature side flow path (73a) provided in the refrigeration supercooling heat exchanger (73). The second branch end is connected to a discharge pipe (76) connected to the discharge side of the booster compressor (71) via a check valve (CV15) connected to the first refrigeration refrigerant pipe (78). It is connected. The check valve (CV15) is attached in a direction that allows only the flow of refrigerant from the first refrigeration refrigerant pipe (78) to the discharge pipe (76).

  The third branch end is connected to a suction pipe (86) connected to the suction side of the booster compressor (71) via the first refrigeration pressure reducing valve (EV11). The fourth branch end is connected to an inlet of a low temperature side flow path (73b) provided in the refrigeration supercooling heat exchanger (73) through the second refrigeration pressure reducing valve (EV12). . In addition, the refrigerant | coolant piping extended from the outflow port of the said low temperature side flow path (73b) is connected to the middle of the said discharge piping (76).

  Here, the end of the discharge pipe (76) is connected to the refrigeration gas side stop valve (84) of the refrigeration circuit (70a), and the discharge pipe (76) includes an oil separator (77) and A check valve (CV13) is provided. The oil separator (77) is connected to an oil outflow pipe (79) for flowing out the refrigerating machine oil. One end of the oil outflow pipe (79) is connected to the oil outlet of the oil separator (77), and the other end is connected to the suction pipe (86) via a capillary tube (87). The check valve (CV13) is attached in a direction that allows only the flow of refrigerant from the booster compressor (71) toward the refrigeration gas side stop valve (84).

  The end of the second refrigeration refrigerant pipe (83) connected to the outlet of the high temperature side passage (73a) provided in the refrigeration supercooling heat exchanger (73) is connected to the refrigeration expansion valve. It is connected to the inflow end of the refrigeration heat exchanger (72) via (EV10). The outflow end of the refrigeration heat exchanger (72) is connected to the end of the suction pipe (86) extending from the suction side of the booster compressor (71). The refrigeration circuit (70a) is provided with a bypass pipe (75) for connecting the discharge pipe (76) and the suction pipe (86). The bypass pipe (75) is provided with a check valve (CV14) in such a direction as to allow only the refrigerant flow from the suction pipe (86) to the discharge pipe (76).

  The refrigeration supercooling heat exchanger (73) has the high temperature side channel (73a) and the low temperature side channel (73b) as described above, and the high temperature side channel (73a) and the low temperature side channel. The refrigerant flowing through the path (73b) is configured to exchange heat.

  The refrigeration heat exchanger (72) is a cross-fin type fin-and-tube heat exchanger. A refrigeration fan (74) is provided in the vicinity of the refrigeration heat exchanger (72). The refrigeration heat exchanger (72) is configured to exchange heat between the outdoor air sent by the refrigeration fan (74) and the refrigerant flowing in the refrigeration heat exchanger (72).

  The booster compressor (71) is constituted by a hermetic high-pressure dome type scroll compressor. The booster compressor (71) has an electric motor connected to an inverter capable of freely changing the rotation speed of the electric motor within a predetermined range. The inverter can adjust the rotational speed of the electric motor to increase or decrease the operating capacity of the booster compressor (71).

  The refrigeration expansion valve (EV10) is composed of a temperature-sensitive expansion valve, and a temperature-sensitive cylinder of the refrigeration expansion valve (EV10) is connected to a heat transfer tube near the refrigerant outlet in the refrigeration heat exchanger (72). (123) is connected. The first and second refrigeration pressure reducing valves (EV11, EV12) are both electrically operated valves with variable opening degrees.

  The refrigeration circuit (70a) is provided with various sensors and pressure switches. Specifically, the discharge pipe (76) is provided with a discharge pipe temperature sensor (125) for a booster compressor and a high pressure switch (131) for the booster compressor. The discharge pipe temperature sensor (125) for the booster compressor detects the temperature of the discharge pipe (76), and the high pressure switch (131) for the booster compressor detects the discharge pressure and freezes at abnormally high pressure. This is an emergency stop.

  A refrigeration refrigerant temperature sensor (126) is provided in the vicinity of the outlet end of the low temperature side flow path (73b) in the refrigeration subcooling heat exchanger (73). The suction pipe (86) is provided with a booster compressor suction pressure sensor (127) for detecting the suction pressure of the booster compressor (71). A freezer temperature sensor (124) for detecting the temperature of the air in the freezer is provided in the vicinity of the freezing heat exchanger (72).

<Supercooling unit>
The supercooling circuit (10a) of the supercooling unit (10) is shown in FIG. The supercooling circuit (10a) is configured to perform a vapor compression refrigeration cycle.

  Specifically, a supercooling compressor (11) is connected to the supercooling circuit (10a). This supercooling compressor (11), like the compressors (21a, 21b, 21c) of the outdoor unit (20), is composed of a hermetic high-pressure dome type scroll compressor, and the above supercooling compressor In (11), an intermediate port is provided so as to open to the compression chamber at the intermediate pressure position. The motor of the supercooling compressor (11) is connected to an inverter that can freely change the rotational speed of the motor within a predetermined range. By adjusting the rotational speed of the electric motor with this inverter, the operating capacity of the supercooling compressor (11) can be increased or decreased.

  A condenser (12) is connected to the end of the supercooling circuit discharge pipe (2) connected to the discharge side of the supercooling compressor (11). Specifically, the end of the supercooling circuit discharge pipe (2) is connected to the inflow end of the condenser (12). Here, the supercooling circuit discharge pipe (2) is provided with a check valve (CV1) in such a direction as to permit the flow of refrigerant from the supercooling compressor (11) to the condenser (12). ing.

  The condenser (12) is a cross-fin type fin-and-tube heat exchanger. A blower fan (17) for the supercooling unit is provided in the vicinity of the condenser (12). The condenser (12) is configured to exchange heat between outdoor air sent by the blower fan (17) for the supercooling unit and the refrigerant flowing in the condenser (12).

  A supercooling expansion valve (EV1) is connected to the end of the eleventh refrigerant pipe (high pressure liquid line) (3) connected to the outflow end of the condenser (12). Further, an intermediate pressure expansion valve (EV2) is connected to an end of the branch pipe (3a) connected to branch from the eleventh refrigerant pipe (3). The eleventh refrigerant pipe (3) constitutes a high pressure liquid line.

  The supercooling expansion valve (EV1) and the intermediate pressure expansion valve (EV2) are both electric expansion valves whose opening degrees can be adjusted.

  A first supercooling heat exchanger (14) is connected to the end of the twelfth refrigerant pipe (7a) connected to the outlet side of the supercooling expansion valve (EV1). The second subcooling heat exchanger (15) is connected to the end of the thirteenth refrigerant pipe (7b) connected to the outlet side of the intermediate pressure expansion valve (EV2).

  The first subcooling heat exchanger (14) has a first high temperature side channel (14a) separately from the first low temperature side channel (14b) described above, and the first high temperature side channel (14a). And it is comprised so that the refrigerant | coolants which flow through a 1st low temperature side flow path (14b) can exchange heat. Here, the supercooling circuit (10a) is provided with a first connection pipe (19b) connecting the second end (18b) and the fourth end (18d) of the supercooling circuit (10a), The first high-temperature channel (14a) of the first subcooling heat exchanger (14) communicates with the first connection pipe (19b). That is, the first high temperature side flow path (14a) is connected to the first liquid side connection pipe (80b, 80d) via the first connection pipe (19b).

  The second subcooling heat exchanger (15) has a second high temperature side channel (15a) separately from the second low temperature side channel (15b) described above, and the second high temperature side channel (15a). And it is comprised so that the refrigerant | coolants which flow through a 2nd low temperature side flow path (15b) can exchange heat. Here, the supercooling circuit (10a) is provided with a second connection pipe (19a) connecting the first end (18a) and the third end (18c) of the supercooling circuit (10a), The second high-temperature channel (15a) of the second subcooling heat exchanger (15) communicates with the second connection pipe (19a). That is, the second high temperature side flow path (15a) is connected to the second liquid side connection pipe (80a, 80c) via the second connection pipe (19a).

  And the edge part of the 14th refrigerant | coolant piping (4) connected to the exit side of the 1st low temperature side flow path (14b) in the said 1st subcooling heat exchanger (14) is the said compressor for supercooling (11). ) And the end of the fifteenth refrigerant pipe (5) connected to the outlet side of the second low temperature side flow path (15b) in the second subcooling heat exchanger (15) It is connected to the intermediate port of the cooling compressor (11).

  The twelfth refrigerant pipe (7a) and the fourteenth refrigerant pipe (4) constitute a low-pressure line (7a, 4) through which the low-pressure refrigerant decompressed by the supercooling expansion valve (EV1) flows. The thirteenth refrigerant pipe (7b) and the fifteenth refrigerant pipe (5) constitute an intermediate pressure line (7b, 5) through which the intermediate pressure refrigerant decompressed by the intermediate pressure expansion valve (EV2) flows.

  The subcooling circuit (10a) is provided with a sixteenth refrigerant pipe (6) branched from the fifteenth refrigerant pipe (5) and connected in the middle of the fourteenth refrigerant pipe (4). The sixteenth refrigerant pipe (6) constitutes a communication path (6) that connects the intermediate pressure line (7b, 5) and the low pressure line (7a, 4). The sixteenth refrigerant pipe (6) is connected to an electromagnetic valve (second on-off valve) (SV2) that opens and closes the sixteenth refrigerant pipe (6).

  The supercooling circuit (10a) is provided with various sensors and pressure switches. Specifically, the supercooling circuit discharge pipe (2) is provided with a supercooling circuit discharge pipe temperature sensor (100). The supercooling circuit discharge pipe temperature sensor (100) detects the temperature of the supercooling circuit discharge pipe (2).

  The fourteenth refrigerant pipe (4) is provided with a supercooling circuit suction temperature sensor (101) and a supercooling circuit suction pressure sensor (99) near the suction port of the supercooling compressor (11). Yes. An outside air temperature sensor (105) for detecting an outside air temperature is provided in the vicinity of the blower fan (17) for the supercooling unit.

  A first liquid temperature sensor (102) is provided near the outflow end of the first high-temperature side flow path (14a) of the first subcooling heat exchanger (14) in the first connection pipe (19b). A second liquid temperature sensor (103) is provided in the vicinity of the outflow end of the second high temperature side channel (15a) of the second subcooling heat exchanger (15) in the two-connection pipe (19a).

  An intermediate liquid temperature sensor (104) is provided in the vicinity of the outflow end of the second low-temperature side flow path (15b) of the second subcooling heat exchanger (15) in the fifteenth refrigerant pipe (5). .

-Driving action-
The refrigeration apparatus cools the interior of the refrigerated showcase (60) and the refrigerated showcase (70) and cools the store with the indoor unit (50), and the refrigerated showcase (60) and the refrigerated showcase (70). ) And the heating operation of heating the store with the indoor unit (50) can be switched.

<Cooling operation>
In the cooling operation, all four-way switching valves (26a, 26b, 26c) are set to the first state. In addition, the outdoor expansion valve (EV6) is set to a fully closed state. Further, the opening degrees of the indoor expansion valve (EV8), the refrigeration expansion valve (EV9), and the refrigeration expansion valve (EV10) are adjusted as appropriate. In addition, the four fans (27, 54, 64, 74), the three compressors (21a, 21b, 21c), and the booster compressor (71) are in operation. In the supercooling unit (10), the opening degrees of the supercooling expansion valve (EV1) and the intermediate pressure expansion valve (EV2) are adjusted as appropriate, and the supercooling compressor (11) and the supercooling unit (10) are adjusted. The unit blower fan (17) is appropriately operated. The operation of the supercooling unit (10) will be described later.

  Each high-pressure gas refrigerant compressed to a predetermined pressure by the first, second, and third compressors (21a, 21b, 21c) is discharged from each compressor (21a, 21b, 21c). The high-pressure gas refrigerant discharged from each compressor (21a, 21b, 21c) passes through each discharge pipe (30a, 30b, 30c) and then flows into each oil separator (49a, 49b, 49c). In each oil separator (49a, 49b, 49c), the refrigeration oil is separated from the high-pressure gas refrigerant. The separated refrigeration oil is temporarily stored in each oil separator (49a, 49b, 49c), and then injected into each of the oil pipes (47a, 47b, 47c) and the oil outflow merging pipe (44) ( 28).

  The refrigerating machine oil that has flowed into the injection pipe (28) once merges with the refrigerant flowing through the injection pipe (28) and then diverts and passes through the flow rate adjustment valves (EV3, EV4, EV5), and then the compressors. The air is sucked into the compression chamber at the intermediate pressure position through the intermediate ports (21a, 21b, 21c).

  On the other hand, the high-pressure gas refrigerant from which the refrigerating machine oil has been separated flows out of the oil separators (49a, 49b, 49c) and then joins in the discharge junction pipe (31). The high-pressure gas refrigerant joined in the discharge junction pipe (31) flows into the outdoor heat exchanger (22) through the first and second four-way switching valves (26a, 26b).

  In the outdoor heat exchanger (22), the high-pressure gas refrigerant dissipates heat to the outdoor air and condenses to become a high-pressure refrigerant. The high-pressure refrigerant flows into the receiver (23) through the third refrigerant pipe (32).

  In the receiver (23), the high-pressure refrigerant is temporarily stored and then flows out from the receiver (23). The high-pressure refrigerant that has flowed out of the receiver (23) is diverted after flowing into the fourth refrigerant pipe (34), and one of the high-pressure refrigerant is the high-temperature channel (24a) of the first outdoor subcooling heat exchanger (24). The other flows into the high temperature side flow path of the second outdoor subcooling heat exchanger (25).

  In addition, when the solenoid valve (SV0) of the vent pipe (27) connected to the receiver (23) is in an open state, the high-pressure gas refrigerant in the receiver (23) passes through the vent pipe (27). Then, it flows to the injection pipe (28).

  The high-pressure refrigerant flowing into the high temperature side flow path (24a) of the first outdoor subcooling heat exchanger (24) passes through the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24). After being radiated and cooled to the flowing reduced-pressure refrigerant, it flows out of the high-temperature side flow path (24a). This cooling increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the high-temperature side flow path (24a) is divided through the fifth refrigerant pipe (35), one flows into the injection pipe (28), and the other flows into the second liquid-side closing valve ( After passing through 43d) and flowing out of the outdoor circuit (20a), it flows into the first pipe (80b) of the first liquid side connecting pipe (80b, 80d).

  The high-pressure refrigerant flowing into the injection pipe (28) is depressurized to a predetermined pressure by the outdoor supercooling pressure reducing valve (EV7) to become a reduced pressure refrigerant, and then the second outdoor supercooling heat exchanger (25 ) And the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24). And when this decompression refrigerant | coolant passes each low temperature side flow path, it absorbs heat from the high pressure refrigerant | coolant which flows through each high temperature side flow path corresponding to each low temperature side flow path, and is heated. By this heating, the reduced-pressure refrigerant evaporates. The evaporated refrigerant under reduced pressure is diverted, and the flow rate is adjusted when passing through the flow rate adjusting valves (EV3, EV4, EV5). Then, the decompressed refrigerant whose flow rate is adjusted by the flow rate adjusting valves (EV3, EV4, EV5) is injected into the compression chambers at the intermediate pressure positions in the compressors (21a, 21b, 21c).

  The opening degree of the outdoor supercooling pressure reducing valve (EV7) is adjusted so that the detected temperature of the injection temperature sensor (112) approaches a predetermined temperature. The opening of each flow rate adjustment valve (EV3, EV4, EV5) is determined by the discharge pipe (30a, 30b, 21c) of each compressor (21a, 21b, 21c) corresponding to each flow rate adjustment valve (EV3, EV4, EV5). The detection temperature of the discharge pipe temperature sensor (106, 107, 108) provided in 30c) is adjusted so as to approach a predetermined temperature.

  On the other hand, the high-pressure refrigerant that has flowed into the high-temperature side flow path of the second outdoor subcooling heat exchanger (25) becomes the reduced-pressure refrigerant that flows through the low-temperature side flow path of the second outdoor subcooling heat exchanger (25). After being radiated and cooled, it flows out of the high temperature side flow path. This cooling increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the high-temperature side flow path passes through the sixth refrigerant pipe (36), passes through the first liquid-side closing valve (43c), and flows out of the outdoor circuit (20a). It flows into the first pipe (80a) of the liquid side communication pipe.

  The high-pressure refrigerant that has flowed into the first pipe (80b) of the first liquid side communication pipe flows into the supercooling circuit (10a) from the second end (18b) of the supercooling circuit (10a), and then It flows into the 1st high temperature side flow path (14a) of the said 1st subcooling heat exchanger (14) through 1 connection piping (19b). After the high-pressure refrigerant flowing into the first high-temperature side channel (14a) is cooled by releasing heat to the low-pressure refrigerant flowing through the first low-temperature side channel (14b) of the first supercooling heat exchanger (14). The first high temperature side flow path (14a) flows out. This cooling increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the first high-temperature channel (14a) passes through the fourth end (18d) of the supercooling circuit (10a) and flows out of the supercooling circuit (10a), and then It flows into the second pipe (80d) of the liquid side connecting pipe (80b, 80d).

  The high-pressure refrigerant that has flowed into the second pipe (80d) of the first liquid side connecting pipe is divided, and one flows from the liquid end (65) of the refrigeration circuit (60a) into the refrigeration circuit (60a), and the other Flows into the freezing circuit (70a) from the freezing liquid side shut-off valve (85) of the freezing circuit (70a).

  The high-pressure refrigerant flowing into the refrigeration circuit (60a) is depressurized to a predetermined pressure by the refrigeration expansion valve (EV9) to become a low-pressure refrigerant, and then flows to the refrigeration heat exchanger (62). In the refrigeration heat exchanger (62), the low-pressure refrigerant absorbs heat from the air in the refrigerated showcase (60) and evaporates. The evaporation temperature of the low-pressure refrigerant at this time is about −10 ° C. The inside of the refrigerated showcase (60) is cooled by the evaporation of the low-pressure refrigerant. The refrigerant evaporated in the refrigeration heat exchanger (62) flows out of the refrigeration circuit (60a) through the gas end (66) of the refrigeration circuit (60a).

  On the other hand, the high-pressure refrigerant flowing into the refrigeration circuit (70a) is divided into four through the first refrigeration refrigerant pipe (78).

  The high-pressure refrigerant flowing out from the first branch end of the first refrigeration refrigerant pipe (78) dissipates heat to the reduced-pressure refrigerant flowing through the low-temperature side flow path (73b) of the refrigeration supercooling heat exchanger (73) and cools it. Is done. This cooling increases the degree of supercooling of the high-pressure refrigerant. After the high-pressure refrigerant that has flowed out of the high-temperature side flow path (73a) passes through the second refrigeration refrigerant pipe (83) and is reduced to a predetermined pressure by the refrigeration expansion valve (EV10) to become a low-pressure refrigerant. And flows into the refrigeration heat exchanger (72). The low-pressure refrigerant flowing into the refrigeration heat exchanger (72) absorbs heat from the air in the refrigeration showcase (70) and evaporates, and then flows out of the refrigeration heat exchanger (72). Here, the evaporation temperature of the low-pressure refrigerant is about −40 ° C., and the inside of the refrigeration showcase (70) is cooled by the evaporation of the low-pressure refrigerant. The low-pressure refrigerant flowing out of the refrigeration heat exchanger (72) is sucked into the booster compressor (71) through the suction pipe (86).

  The low-pressure refrigerant sucked into the booster compressor (71) is compressed to a predetermined pressure, and then discharged from the booster compressor (71), and is refrigerated in the discharge pipe (76) and the refrigeration circuit (70a). The refrigerant flows out of the refrigeration circuit (70a) through the industrial gas side shutoff valve (84).

  The high-pressure refrigerant flowing out from the second branch end of the first refrigeration refrigerant pipe (78) is, for example, when the booster compressor (71) is stopped or discharged from the booster compressor (71). When the pressure is lower than the pressure of the high-pressure refrigerant flowing out from the second branch end, it passes through the check valve (CV15) and flows into the discharge pipe (76). In some cases, the high-pressure refrigerant flowing into the discharge pipe (76) merges with the refrigerant discharged from the booster compressor (71), and then the refrigeration gas side stop valve ( 84) and then flows out of the refrigeration circuit (70a).

  The high-pressure refrigerant flowing out from the third branch end of the first refrigeration refrigerant pipe (78) flows into the first refrigeration decompression valve (EV11) and is depressurized to a predetermined pressure to become a depressurized refrigerant. Then, the first freezing pressure reducing valve (EV11) flows out. The reduced pressure refrigerant flowing out of the first refrigeration pressure reducing valve (EV11) is injected into the suction pipe (86) and merges with the low pressure refrigerant flowing from the refrigeration heat exchanger (72). The merged refrigerant is sucked into the booster compressor (71). The opening degree of the first refrigeration pressure reducing valve (EV11) is adjusted so that the detected pressure value of the suction pressure sensor (127) does not become lower than a predetermined value.

  The high-pressure refrigerant flowing out from the fourth branch end of the first refrigeration refrigerant pipe (78) flows into the second refrigeration decompression valve (EV12) and is depressurized to a predetermined pressure to become a depressurized refrigerant. Then, the second refrigeration pressure reducing valve (EV12) flows out. Then, the decompressed refrigerant that has flowed out of the second refrigeration decompression valve (EV12) passes through the low-temperature side flow path (73b) of the refrigeration supercooling heat exchanger (73). During this passage, the reduced-pressure refrigerant is heated by absorbing heat from the high-pressure refrigerant flowing in the high-temperature side flow path (73a) of the refrigeration supercooling heat exchanger (73). By this heating, the reduced-pressure refrigerant evaporates. The evaporated refrigerant under reduced pressure is injected into the discharge pipe (76) and merged with the refrigerant discharged from the booster compressor (71), and then the freezing gas side closing valve (70a) 84) and then flows out of the refrigeration circuit (70a). The opening degree of the second refrigeration pressure reducing valve (EV12) is adjusted so that the temperature detected by the refrigeration refrigerant temperature sensor (126) does not become higher than a predetermined value.

  After the low-pressure refrigerant that has flowed out of the refrigeration circuit (60a) and the low-pressure refrigerant that has flowed out of the refrigeration circuit (70a) merge in the second gas side connection pipe (95), the low-pressure refrigerant after the merged becomes the outdoor circuit It flows into the outdoor circuit (20a) from the second gas side closing valve (43b) of (20a).

  On the other hand, after the high-pressure refrigerant flowing into the first pipe (80a) of the second liquid side connecting pipe flows into the supercooling circuit (10a) from the first end (18a) of the supercooling circuit (10a), It flows into the 2nd high temperature side flow path (15a) of the said 2nd subcooling heat exchanger (15) through the said 2nd connection piping (19a). The high-pressure refrigerant flowing into the second high-temperature side flow path (15a) was cooled by releasing heat to the intermediate-pressure refrigerant flowing through the second low-temperature side flow path (15b) of the second supercooling heat exchanger (15). Then, it flows out out of the second low temperature side channel (15b). This cooling increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the second high-temperature channel (15a) passes through the third end (18c) of the supercooling circuit (10a) and flows out of the supercooling circuit (10a), and then the second It flows into the second pipe (80c) of the liquid side connecting pipe (80a, 80c).

  The high-pressure refrigerant that has flowed into the second pipe (80c) of the second liquid side connecting pipe flows into the indoor circuit (50a) from the liquid end (56) of the indoor circuit (50a).

  The high-pressure refrigerant flowing into the indoor circuit (50a) is depressurized to a predetermined pressure by the indoor expansion valve (EV8) to become a low-pressure refrigerant, and then flows into the indoor heat exchanger (52). In the indoor heat exchanger (52), the low-pressure refrigerant absorbs heat from the air in the store and evaporates. The evaporation temperature of the low-pressure refrigerant at this time is about 5 ° C. And the inside of a store is cooled by evaporation of this low-pressure refrigerant. The refrigerant evaporated in the indoor heat exchanger (52) flows out of the indoor circuit (50a) through the gas end (55) of the indoor circuit (50a). The opening of the indoor expansion valve (EV8) is adjusted so that the temperature detected by the first indoor refrigerant temperature sensor (118) approaches a predetermined value.

  The low-pressure refrigerant flowing out of the indoor circuit (50a) passes through the first gas side connecting pipe (92), and then from the first gas side shut-off valve (43a) of the outdoor circuit (20a) to the outdoor circuit (20a). Flow into.

  In the outdoor circuit (20a), the low-pressure refrigerant flowing from the first gas-side stop valve (43a) passes through the first refrigerant pipe (41) and the first and second four-way switching valves (26a, 26b). After that, the air is sucked into the third compressor (21c) from the third suction pipe (40c). The low-pressure refrigerant sucked into the third compressor (21c) is compressed to a predetermined pressure while the intermediate-pressure refrigerant is injected from the intermediate port in the middle of the compression, and becomes a high-pressure refrigerant, and the third compressor (21c) ) Again.

  The low-pressure refrigerant flowing from the second gas side shut-off valve (43b) passes through the branch pipe (40d) of the first suction pipe (40a) and partly from the first suction pipe (40a). 1 is sucked into the compressor (21a), and the remainder passes through the check valve (CV17) and the third four-way selector valve (26c), and then passes from the second suction pipe (40b) to the second compressor (21b). Inhaled. The low-pressure refrigerant sucked into the first and second compressors (21a, 21b) is compressed to a predetermined pressure while the intermediate-pressure refrigerant is injected from each intermediate port in the middle of the compression, and becomes high-pressure gas refrigerant. It is discharged again from the first and second compressors (21a, 21b).

  As described above, in the refrigeration apparatus, the refrigerant circulates in the refrigerant circuit (1), whereby the cooling operation is performed, the interior of the refrigerated showcase (60) and the refrigeration showcase (70) is cooled, and the indoor unit Use (50) to cool the store.

  As described above, the second compressor (21b) is used to suck the refrigerant flowing out of the refrigerated showcase (60) and the refrigerated showcase (70). By switching only the third four-way switching valve (26c) (26a, 26b, 26c) to the second state, the second compressor (21b) sucks the refrigerant flowing out of the indoor unit (50). Can be used for

<Operation of supercooling circuit>
The high-pressure gas refrigerant compressed to a predetermined pressure by the supercooling compressor (11) flows into the condenser (12) through the supercooling circuit discharge pipe (2). In the condenser (12), the high-pressure gas refrigerant dissipates heat to the outdoor air and condenses to become a high-pressure refrigerant in a liquid phase or a two-phase state. This high-pressure refrigerant flows out from the condenser (12), then flows into the eleventh refrigerant pipe (3), and then diverts, one into the supercooling expansion valve (EV1), and the other as the intermediate pressure expansion valve. Flows into (EV2).

  The high-pressure refrigerant that has flowed into the supercooling expansion valve (EV1) is depressurized to a predetermined pressure to become a low-pressure refrigerant, and then flows out of the supercooling expansion valve (EV1) to exchange the first supercooling heat exchange. Flows into the first low temperature side flow path (14b) of the vessel (14). The low-pressure refrigerant that has flowed into the first low-temperature side channel (14b) absorbs heat from the high-pressure refrigerant in the first high-temperature side channel (14a) and evaporates, and then flows out from the first low-temperature side channel (14b). .

  On the other hand, the high-pressure refrigerant flowing into the intermediate pressure expansion valve (EV2) is decompressed to a predetermined pressure and becomes intermediate pressure refrigerant having a pressure higher than that of the low-pressure refrigerant, and then flows out from the intermediate pressure expansion valve (EV2). And it flows in into the 2nd low temperature side flow path (15b) of the said 2nd subcooling heat exchanger (15). The intermediate-pressure refrigerant that has flowed into the second low-temperature side channel (15b) evaporates by absorbing heat from the high-pressure refrigerant in the second high-temperature side channel (15a) and then flows out from the second low-temperature side channel (15b). To do.

  Here, when the solenoid valve (SV2) of the sixteenth refrigerant pipe (6) is open, a part of the intermediate pressure refrigerant flowing out of the second subcooling heat exchanger (15) is transferred to the sixteenth refrigerant pipe (6 ) And the low-pressure refrigerant flowing out from the first supercooling heat exchanger (14), and then sucked into the compression chamber at the suction pressure position from the suction port of the supercooling compressor (11). On the other hand, when the solenoid valve (SV2) is closed, the low-pressure refrigerant is sucked into the compression chamber at the suction pressure position from the suction port of the supercooling compressor (11) without joining the intermediate-pressure refrigerant. The

  In the supercooling compressor (11), when the compression chamber comes to an intermediate pressure position in the middle of changing from the suction pressure position to the discharge pressure position, it evaporates in the second supercooling heat exchanger (15). The intermediate pressure refrigerant is injected into the compression chamber at the intermediate pressure position. The injected intermediate pressure refrigerant merges with the low-pressure refrigerant compressed halfway, and then is compressed to a predetermined pressure to become a high-pressure refrigerant, which is discharged from the supercooling compressor (11). The high-pressure refrigerant discharged from the supercooling compressor (11) again flows into the condenser (12) through the supercooling circuit discharge pipe (2).

  As described above, the refrigerant circulates in the supercooling circuit (10a), and is sent to the refrigerated showcase (60) and the freezer showcase (70) through the first liquid side connecting pipe (80b, 80d). The high-pressure refrigerant is cooled by the first subcooling heat exchanger (14), and the high-pressure refrigerant sent to the indoor unit (50) through the second liquid side connecting pipe (80a, 80c) is the second subcooling heat exchanger ( Cooled in 15).

<Heating operation>
In the heating operation, only the first four-way switching valve (26a) is set to the second state. Moreover, the opening degree of the outdoor expansion valve (EV6) is set to a fully closed state. Further, the opening degrees of the indoor expansion valve (EV8), the refrigeration expansion valve (EV9), and the refrigeration expansion valve (EV10) are adjusted as appropriate. In addition, the three fans (54, 64, 74) excluding the outdoor fan (27), the three compressors (21a, 21b, 21c), and the booster compressor (71) are in operation. In the supercooling unit (10), the opening degree of the intermediate pressure expansion valve (EV2) is set to a fully closed state. Further, the opening degree of the supercooling expansion valve (EV1) is appropriately adjusted, and the supercooling compressor (11) and the blower fan (17) for the supercooling unit are appropriately operated. The operation of the supercooling unit (10) will be described later.

  Each high-pressure gas refrigerant compressed to a predetermined pressure by the first, second, and third compressors (21a, 21b, 21c) is discharged from each compressor (21a, 21b, 21c). The high-pressure gas refrigerant discharged from each compressor (21a, 21b, 21c) passes through each discharge pipe (30a, 30b, 30c) and then flows into each oil separator (49a, 49b, 49c). In each oil separator (49a, 49b, 49c), the refrigeration oil is separated from the high-pressure gas refrigerant.

  The flow of refrigeration oil returned to the suction side of each compressor (21a, 21b, 21c) from the refrigeration oil separated by each oil separator (49a, 49b, 49c) is the same flow as the cooling operation, so the explanation is Omitted.

  The high-pressure gas refrigerant that has flowed out of the oil separators (49a, 49b, 49c) joins in the discharge junction pipe (31). The high-pressure gas refrigerant joined in the discharge junction pipe (31) passes through the first gas-side closing valve (43a) through the first four-way switching valve (26a) and the first refrigerant pipe (41). And flows out of the outdoor circuit (20a).

  The high-pressure gas refrigerant that has flowed out of the outdoor circuit (20a) flows into the indoor circuit (50a) from the gas end (55) of the indoor circuit (50a) through the first gas side connection pipe (92). The high-pressure gas refrigerant that has flowed into the indoor circuit (50a) flows into the indoor heat exchanger (52). In the indoor heat exchanger (52), the high-pressure gas refrigerant dissipates heat to the indoor air, condenses, becomes a high-pressure refrigerant in a liquid phase or a two-phase state, and flows out of the indoor heat exchanger (52). Here, the indoor air is heated by absorbing the heat of condensation of the high-pressure gas refrigerant. Thereby, the room is heated.

  The high-pressure refrigerant that has flowed out of the indoor heat exchanger (52) flows into the indoor expansion valve (EV8), is depressurized to a predetermined pressure, becomes an intermediate-pressure refrigerant, and then flows out of the indoor expansion valve (EV8). To do. The intermediate pressure refrigerant flowing out of the indoor expansion valve (EV8) passes through the liquid end (56) of the indoor circuit (50a) and flows out of the indoor circuit (50a).

  The intermediate pressure refrigerant that has flowed out of the indoor circuit (50a) passes through the second pipe (80c) of the second liquid side connecting pipe and passes through the third end (18c) of the supercooling circuit (10a). After flowing into the cooling circuit (10a), it flows into the second high-temperature side flow path (15a) of the second subcooling heat exchanger (15) through the second connection pipe (19a). At this time, as described above, since the opening of the intermediate pressure expansion valve (EV2) provided on the second low temperature side flow path (15b) side is in a fully closed state, the second high temperature side flow path (15a) The inflowing intermediate pressure refrigerant flows out of the second high temperature side channel (15a) without being subjected to heat exchange.

  The intermediate pressure refrigerant that has flowed out of the second high-temperature side flow path (15a) passes through the second connection pipe (19a), passes through the first end (18a) of the supercooling circuit (10a), and is supercooled. Out of circuit (10a). The intermediate pressure refrigerant that has flowed out of the supercooling circuit (10a) passes through the first pipe (80a) of the second liquid side connection pipe and passes through the first liquid side shut-off valve (43c) of the outdoor circuit (20a). It flows into the outdoor circuit (20a). The intermediate pressure refrigerant flowing into the outdoor circuit (20a) passes through the seventh refrigerant pipe (37), the receiver (23), and the fourth refrigerant pipe (34), and then passes through the first outdoor subcooling heat exchanger (24). Flows into the high temperature side channel (24a).

  The intermediate pressure refrigerant flowing into the high temperature side flow path (24a) of the first outdoor subcooling heat exchanger (24) is converted into the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24). After being dissipated and cooled by the reduced-pressure refrigerant flowing through the refrigerant, the refrigerant flows out of the high-temperature channel (24a). This cooling increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the high-temperature side flow path (24a) is divided through the fifth refrigerant pipe (35), one flows into the injection pipe (28), and the other flows into the second liquid-side closing valve ( After passing through 43d) and flowing out of the outdoor circuit (20a), it flows into the first pipe (80b) of the first liquid side connecting pipe.

  The intermediate pressure refrigerant flowing into the injection pipe (28) is reduced to a predetermined pressure by the outdoor supercooling pressure reducing valve (EV7) to become a reduced pressure refrigerant, and then the second outdoor supercooling heat exchanger ( 25) passes through the low temperature side flow path without exchanging heat and flows into the low temperature side flow path (24b) of the first outdoor supercooling heat exchanger (24). The reduced-pressure refrigerant that has flowed into the low-temperature channel (24b) absorbs heat from the intermediate-pressure refrigerant flowing through the high-temperature channel (24a) of the first outdoor subcooling heat exchanger (24) and evaporates. The evaporated refrigerant under reduced pressure is diverted, and the flow rate is adjusted when passing through the flow rate adjusting valves (EV3, EV4, EV5). Then, the decompressed refrigerant whose flow rate is adjusted by the flow rate adjusting valves (EV3, EV4, EV5) is injected into the compression chambers at the intermediate pressure positions in the compressors (21a, 21b, 21c).

  On the other hand, the intermediate-pressure refrigerant that has flowed into the first pipe (80b) of the first liquid side connecting pipe flows into the supercooling circuit (10a) from the second end (18b) of the supercooling circuit (10a). After flowing into the supercooling circuit (10a), it is sucked into the first and second compressors (21a, 21b) of the outdoor circuit (20a) through the refrigeration circuit (60a) and the refrigeration circuit (70a). After that, the flow of the refrigerant until it is discharged again is the same as that in the cooling operation, and is omitted.

  As described above, in the refrigeration apparatus, the refrigerant circulates in the refrigerant circuit (1), whereby the cooling operation is performed, the interior of the refrigerated showcase (60) and the refrigeration showcase (70) is cooled, and the indoor unit Heat the store at (50).

<Operation of supercooling circuit>
The high-pressure gas refrigerant compressed to a predetermined pressure by the supercooling compressor (11) flows into the condenser (12) through the supercooling circuit discharge pipe (2). In the condenser (12), the high-pressure gas refrigerant dissipates heat to the outdoor air and condenses to become a high-pressure refrigerant in a liquid phase or a two-phase state. The high-pressure refrigerant flows out from the condenser (12) and then flows into the eleventh refrigerant pipe (3). Here, as described above, since the intermediate pressure expansion valve (EV2) is set to a fully closed state, all of the high-pressure refrigerant flowing into the eleventh refrigerant pipe (3) is supercooled expansion valve (EV1). ).

  The high-pressure refrigerant that has flowed into the supercooling expansion valve (EV1) is depressurized to a predetermined pressure to become a low-pressure refrigerant, and then flows out of the supercooling expansion valve (EV1) to exchange the first supercooling heat exchange. Flows into the first low temperature side flow path (14b) of the vessel (14). The low-pressure refrigerant that has flowed into the first low-temperature side channel (14b) absorbs heat from the high-pressure refrigerant in the first high-temperature side channel (14a) and evaporates, and then flows out from the first low-temperature side channel (14b). . The low-pressure refrigerant that has flowed out of the first low-temperature channel (14b) is sucked into the supercooling compressor (11) and compressed to a predetermined pressure to become a high-pressure gas refrigerant, and the supercooling compressor (11 ). The high-pressure refrigerant discharged from the supercooling compressor (11) again flows into the condenser (12) through the supercooling circuit discharge pipe (2).

  As described above, the refrigerant circulates in the supercooling circuit (10a), and is sent to the refrigerated showcase (60) and the freezer showcase (70) through the first liquid side connecting pipe (80b, 80d). The high-pressure refrigerant is cooled by the first subcooling heat exchanger (14).

  In the case of the heating operation described above, when the cooling load of each showcase (60, 70) becomes larger than the present, and the indoor heat exchanger (52) alone cannot sufficiently radiate the high-pressure refrigerant, The second four-way switching valve (26b) is switched to the second state together with the first four-way switching valve (26a), and the opening degree is adjusted as necessary without fully closing the outdoor expansion valve (EV6). By doing so, the high-pressure refrigerant can be radiated not only by the indoor heat exchanger (52) but also by the outdoor heat exchanger (22).

-Effect of Embodiment 1-
According to the first embodiment, in the supercooling compressor (11) during the cooling operation, the low pressure refrigerant sucked from the low pressure line (7a, 4) is not compressed as it is, but in the middle of the compression, the intermediate pressure is compressed. The intermediate pressure refrigerant sucked from the intermediate pressure line (7b, 5) can be injected into the compression chamber at the position. As a result, the temperature of the high-pressure refrigerant discharged from the supercooling compressor (11) can be lowered compared with the case where the intermediate pressure refrigerant is not sucked, and the compression power in the supercooling compressor (11) can be reduced. Can be reduced.

  In addition, the intermediate pressure refrigerant decompressed by the intermediate pressure expansion valve (EV2) is not directly injected into the compression chamber at the intermediate pressure position, but by the second subcooling heat exchanger (15), the second liquid side connecting pipe. Heat exchange with the high-pressure refrigerant (80a, 80c) can be performed. Thereby, compared with the case where intermediate pressure refrigerant is directly injected into the compression chamber, the high pressure refrigerant in the liquid side connecting pipes (80b, 80d, 80a, 80c) is supplied to the first and second subcooling heat exchangers (14, 15). ) And the degree of supercooling of the high-pressure refrigerant can be increased as compared with the case of cooling only with the first subcooling heat exchanger (14).

  As described above, the compression power of the supercooling compressor (11) of the supercooling circuit (10a) is reduced and the degree of supercooling of the high-pressure refrigerant flowing in the liquid side connecting pipe (80b, 80d, 80a, 80c) is reduced. The cooling capacity of the refrigeration apparatus can be improved by increasing the size.

  Further, according to the first embodiment, during the cooling operation, the high-pressure refrigerant sent to the refrigerated showcase (60) and the refrigerated showcase (70) through the first liquid side connecting pipe (80b, 80d) is the first. The supercooling heat exchanger (14) is supercooled, and the high pressure refrigerant sent to the indoor unit (50) through the second liquid side connecting pipe (80a, 80c) is superheated by the second supercooling heat exchanger (15). Can be cooled. Thereby, the supercooling degree of the high-pressure refrigerant sent to the refrigerated showcase (60) and the refrigeration showcase (70) and the supercooling degree of the high-pressure refrigerant sent to the indoor unit (50) can be made different. For example, when the refrigeration load of the refrigerated showcase (60) and the refrigerated showcase (70) becomes larger than the present time, the opening degree of the supercooling expansion valve (EV1) is adjusted, and the refrigerated showcase ( 60) and the supercooling degree of the high-pressure refrigerant sent to the refrigeration showcase (70) can be increased.

  Further, according to the first embodiment, during the operation of the supercooling unit (10) during the cooling operation, the first low-temperature side flow path (14b) of the first supercooling heat exchanger (14) flows out. When the pressure of the low-pressure refrigerant becomes too low, the intermediate pressure refrigerant that has flowed out of the second low-temperature side passage (15b) of the second subcooling heat exchanger (15) by opening the solenoid valve (SV2) The pressure of the said low-pressure refrigerant | coolant can be made high by flowing in into 14 refrigerant | coolant piping (4). As a result, the suction pressure of the supercooling compressor (11) can be prevented from becoming too low. For example, the supercooling compressor (11) is forcibly stopped due to a decrease in the suction pressure. Can be prevented.

-Modification 1 of Embodiment 1-
The refrigeration apparatus according to Modification 1 of Embodiment 1 shown in FIG. 3 is different from Embodiment 1 in that a third supercooling heat exchanger (16) is newly installed in the supercooling circuit (10a).

  The third subcooling heat exchanger (16) has a third high temperature side channel (16a) and a third low temperature side channel (16b), and the third high temperature side channel (16a) and the third high temperature side channel (16a). 3 The refrigerant flowing through the low temperature side flow path (16b) is configured to exchange heat. As shown in FIG. 3, the third low temperature side flow path (16b) is connected to the low pressure line (7a, 4) of the supercooling circuit (10a) and the third high temperature side flow path (16a). Is connected to the second liquid side connecting pipe (80a, 80c).

  The third high temperature side flow path (16a) is connected to the second high temperature side flow path (15a) of the second subcooling heat exchanger (15) in the second liquid side connection pipe (80a, 80c). Is also located on the second usage side circuit (50a) side.

  With such a configuration, the high pressure refrigerant flowing through the second liquid side connecting pipe (80a, 80c) is connected to the second subcooling heat exchanger (80a, 80c) ( 15) When passing through the second high temperature side flow path (15a), the intermediate pressure refrigerant flowing through the second low temperature side flow path (15b) of the second supercooling heat exchanger (15) is cooled. Become. Then, the high-pressure refrigerant cooled by the second supercooling heat exchanger (15) flows into the third high-temperature side flow path (16a) of the third supercooling heat exchanger (16) and enters the third high-temperature refrigerant. When passing through the side flow path (16a), it is cooled by the low-pressure refrigerant flowing through the third low temperature side flow path (16b) of the third supercooling heat exchanger (16).

  Thus, according to the first modification of the first embodiment, by newly installing the third subcooling heat exchanger (16), the high-pressure refrigerant in the second liquid side connection pipes (80a, 80c) is reduced. The supercooling circuit (10a) can be cooled by both the low-pressure refrigerant and the intermediate-pressure refrigerant. As a result, the second liquid side connecting pipe is compared with the case where the second liquid side connecting pipe (80a, 80c) is used as a high-pressure refrigerant only by the second subcooling heat exchanger (15) as in the first embodiment. The degree of supercooling of the high-pressure refrigerant (80a, 80c) can be increased. As described above, the high pressure refrigerant in the second liquid side connecting pipe (80a, 80c) is cooled by the intermediate pressure refrigerant in the supercooling circuit (10a), and then the low pressure in the supercooling circuit (10a). It is further cooled with a refrigerant. As described above, the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) can be efficiently cooled stepwise in order from the higher one of the intermediate-pressure refrigerant and the low-pressure refrigerant.

  Further, the subcooling circuit (10a) of the refrigeration apparatus according to Modification 1 includes a bypass channel (81) that bypasses the third high temperature side channel (16a) of the third subcooling heat exchanger (16). An electromagnetic valve (first on-off valve) (82) for opening and closing the bypass flow path (81) is provided.

  In this configuration, when the solenoid valve (82) is opened, the bypass passage (81) is opened, and the high-pressure refrigerant cooled by the second subcooling heat exchanger (15) passes through the bypass passage (81). To the indoor circuit (50a). On the other hand, when the solenoid valve (82) is closed, the bypass flow path (81) is closed, and the high-pressure refrigerant cooled by the second subcooling heat exchanger (15) is transferred to the third subcooling heat exchanger (16). ) To the third high temperature side channel (16a). Then, after passing through the third high temperature side channel (16a), after being cooled by the low pressure refrigerant flowing through the third low temperature side channel (16b) of the third supercooling heat exchanger (16), It flows to the indoor circuit (50a).

  Thus, by the opening and closing operation of the solenoid valve (82), the high-pressure refrigerant in the second liquid side connecting pipe (80a, 80c) is supplied to both the second and third subcooling heat exchangers (15, 16). Or it becomes possible to selectively cool only by the second subcooling heat exchanger (15). Thereby, the amount of supercooling of the high-pressure refrigerant flowing through the second liquid side connecting pipe (80a, 80c) can be easily changed.

-Modification 2 of Embodiment 1
Unlike the first modification, the refrigeration apparatus according to the second modification of the first embodiment shown in FIG. 4 has a fourth subcooling heat exchanger (91) newly installed in the supercooling circuit (10a).

 The fourth subcooling heat exchanger (91) includes a fourth high temperature side channel (91a) and a fourth low temperature side channel (91b), and the fourth high temperature side channel (91a) and the fourth high temperature side channel (91a). It is comprised so that the refrigerant | coolants which flow through 4 low temperature side flow paths (91b) may heat-exchange. As shown in FIG. 4, the fourth low temperature side flow path (91b) is connected to the intermediate pressure line (7b, 5) of the supercooling circuit (10a) and the fourth high temperature side flow path (91a). ) Is connected to the first liquid side connecting pipe (80b, 80d).

  The fourth high temperature side flow path (91a) is more than the first high temperature side flow path (14a) of the first subcooling heat exchanger (14) in the first liquid side connection pipe (80b, 80d). Located on the outdoor circuit (20a) side.

  With such a configuration, the high pressure refrigerant flowing through the first liquid side connecting pipe (80b, 80d) is transferred to the fourth subcooling heat exchanger (80b, 80d) connected to the first liquid side connecting pipe (80b, 80d). 91) so as to be cooled by the intermediate pressure refrigerant flowing through the fourth low temperature side channel (91b) of the fourth supercooling heat exchanger (91) when passing through the fourth high temperature side channel (91a). Become. Then, the high-pressure refrigerant cooled by the fourth supercooling heat exchanger (91) flows into the first high-temperature side flow path (14a) of the first supercooling heat exchanger (14) and enters the first high-temperature refrigerant. When passing through the side flow path (14a), it is cooled by the low-pressure refrigerant flowing through the first low temperature side flow path (14b) of the first subcooling heat exchanger (14).

  As described above, according to the second modification of the first embodiment, by newly installing the fourth subcooling heat exchanger (91), the high-pressure refrigerant in the first liquid side connecting pipe (80b, 80d) is reduced. The supercooling circuit (10a) can be cooled by both the low-pressure refrigerant and the intermediate-pressure refrigerant. Thereby, compared with the case where the high pressure refrigerant of the first liquid side communication pipe (80b, 80d) is used only by the first subcooling heat exchanger (14) as in the first embodiment, the first liquid side communication pipe is used. The degree of supercooling of the high-pressure refrigerant (80b, 80d) can be increased. Further, as described above, the high pressure refrigerant in the first liquid side connecting pipe (80b, 80d) is cooled by the intermediate pressure refrigerant in the supercooling circuit (10a), and then the low pressure in the supercooling circuit (10a). It is further cooled with a refrigerant. As described above, the high-pressure refrigerant in the first liquid side connecting pipe (80b, 80d) can be efficiently cooled stepwise in order from the higher one of the intermediate-pressure refrigerant and the low-pressure refrigerant.

<< Embodiment 2 >>
The refrigeration apparatus of Embodiment 2 cools a refrigerated warehouse and a frozen warehouse. The difference between the refrigeration apparatus of Embodiment 2 and the refrigeration apparatus of Embodiment 1 is that the refrigeration apparatus of Embodiment 2 is not provided with an indoor unit (50).

  As shown in FIG. 5, the refrigeration apparatus of Embodiment 2 includes an outdoor unit (20), a refrigeration unit (60), a refrigeration unit (70), and a supercooling unit (10). The outdoor unit (20) and the supercooling unit (10) are installed outdoors, the refrigeration unit (60) is installed in a refrigerated warehouse, and the refrigeration unit (70) is installed in a refrigerated warehouse.

  In this refrigeration apparatus, each circuit (10a, 20a, 60a, 70a) is connected by a connecting pipe, whereby a refrigerant circuit (1) that performs a vapor compression refrigeration cycle is configured. The connecting pipe is composed of a liquid side connecting pipe (93a, 93b, 93c) and a gas side connecting pipe (92). The liquid side connecting pipe (93a, 93b, 93c) has a first pipe (93a), a second pipe (93b), and a third pipe (93c).

  In the liquid side communication pipe (93a, 93b, 93c), the first pipe (93a) is connected to the liquid side shut-off valve (43d) of the outdoor circuit (20a) and the first end (18a) of the supercooling circuit (10a). ), The second pipe (93b) connects the third end (18c) and the second end (18b) of the supercooling circuit (10a), and the third pipe (93c) The fourth end (18d) of the cooling circuit (10a), the liquid end (65) of the refrigeration circuit (60a), and the refrigeration liquid side shut-off valve (85) of the refrigeration circuit (70a) are connected.

  The gas side communication pipe (92) includes a gas side closing valve (43a) of the outdoor circuit (20a), a gas end (66) of the refrigeration circuit (60a), and a refrigeration gas side closing of the refrigeration circuit (70a). Connected to valve (84).

<Outdoor unit>
The outdoor circuit (20a) of the outdoor unit (20) is different from the outdoor circuit (20a) of the refrigeration apparatus according to Embodiment 1 in that the second and third four-way switching valves (26b, 26c) and the second outdoor unit The point is that no supercooling heat exchanger (25) is provided. Only the differences will be described below.

  In the outdoor circuit (20a), in the first four-way switching valve (26a), a discharge pipe (30a, 30b, 30c) having a first port connected to the discharge side of each compressor (21a, 21b, 21c) It is connected to the discharge merging pipe (31), which is the merging pipe, and the second port is the merging pipe of the suction pipe (40a, 40b, 40c) connected to the suction side of each compressor (21a, 21b, 21c) Connected to the suction junction pipe (40), the third port is connected to the outdoor heat exchanger (22), and the fourth port is connected to the gas side shut-off valve (43a) of the outdoor circuit (20a).

  The fourth refrigerant pipe (34) extending from the bottom of the receiver (23) is not branched and connected to the inflow end of the high-temperature channel (24a) in the first outdoor subcooling heat exchanger (24). Has been. The seventh refrigerant pipe (37) branched from between the receiver (23) and the check valve (CV9) in the third refrigerant pipe (32) has an end portion of the fifth refrigerant pipe (35). Connected on the way.

  The refrigeration unit (60) has the same configuration as the refrigeration showcase of the refrigeration apparatus according to Embodiment 1, and the refrigeration unit (70) is the same as the refrigeration showcase of the refrigeration apparatus according to Embodiment 1. Since the supercooling unit (10) has the same configuration as the supercooling unit of the refrigeration apparatus according to Embodiment 1, the description thereof is omitted.

-Driving action-
In the refrigeration apparatus of the second embodiment, the refrigeration unit (60) maintains the inside of the refrigerated warehouse at a predetermined temperature (for example, 5 ° C.), and the refrigeration unit (70) maintains the freezer warehouse at the predetermined temperature (for example, −30 ° C.) The cooling operation is maintained at

  In this cooling operation, the first four-way selector valve (26a) is set to the first state. In addition, the outdoor expansion valve (EV6) is set to a fully closed state. Further, the opening degrees of the refrigeration expansion valve (EV9) and the refrigeration expansion valve (EV10) are adjusted as appropriate. Also, the three fans (27, 64, 74), the three compressors (21a, 21b, 21c), and the booster compressor (71) are in operation. In the supercooling unit (10), the opening degrees of the supercooling expansion valve (EV1) and the intermediate pressure expansion valve (EV2) are adjusted as appropriate, and the supercooling compressor (11) and the supercooling unit (10) are adjusted. The unit blower fan (17) is appropriately operated.

  Each high-pressure gas refrigerant compressed to a predetermined pressure by the first, second, and third compressors (21a, 21b, 21c) is discharged from each compressor (21a, 21b, 21c). The high-pressure gas refrigerant discharged from each compressor (21a, 21b, 21c) passes through each discharge pipe (30a, 30b, 30c) and then flows into each oil separator (49a, 49b, 49c). In each oil separator (49a, 49b, 49c), the refrigeration oil is separated from the high-pressure gas refrigerant.

  The flow of the refrigeration oil returned to the suction side of each compressor (21a, 21b, 21c) by the refrigeration oil separated by each oil separator (49a, 49b, 49c) is the same flow as the refrigeration apparatus according to the first embodiment. Therefore, the description is omitted.

  The high-pressure gas refrigerant that has flowed out of the oil separators (49a, 49b, 49c) joins in the discharge junction pipe (31). The high-pressure gas refrigerant merged in the discharge merging pipe (31) flows into the outdoor heat exchanger (22) through the first four-way switching valve (26a).

  In the outdoor heat exchanger (22), the high-pressure gas refrigerant dissipates heat to the outdoor air and condenses into a liquid-phase or two-phase high-pressure refrigerant. The high-pressure refrigerant flows into the receiver (23) through the third refrigerant pipe (32).

  In the receiver (23), the high-pressure refrigerant is temporarily stored and then flows out from the receiver (23). The high-pressure refrigerant that has flowed out of the receiver (23) flows into the fourth refrigerant pipe (34), and then flows into the high-temperature channel (24a) of the first outdoor subcooling heat exchanger (24).

  In addition, when the solenoid valve (SV0) of the vent pipe (27) connected to the receiver (23) is in an open state, the high-pressure gas refrigerant in the receiver (23) passes through the vent pipe (27). Then, it flows to the injection pipe (28).

  The high-pressure refrigerant flowing into the high temperature side flow path (24a) of the first outdoor subcooling heat exchanger (24) passes through the low temperature side flow path (24b) of the first outdoor subcooling heat exchanger (24). After being radiated and cooled to the flowing reduced-pressure refrigerant, it flows out of the high-temperature side flow path (24a). This cooling increases the degree of supercooling of the high-pressure refrigerant.

  The high-pressure refrigerant that has flowed out of the high-temperature side flow path (24a) flows into the fifth refrigerant pipe (35) and then is divided, one flows into the injection pipe (28), and the other flows into the liquid-side shut-off valve ( After passing through 43d) and flowing out of the outdoor circuit (20a), it flows to the first pipe (93a) of the liquid side connecting pipe.

  The high-pressure refrigerant flowing into the injection pipe (28) is depressurized to a predetermined pressure by the outdoor supercooling pressure reducing valve (EV7) to become a reduced pressure refrigerant, and then the first outdoor supercooling heat exchanger (24 ) Through the low temperature side flow path (24b). And this decompression refrigerant absorbs heat from the high temperature side channel (24a) of the 1st outdoor supercooling heat exchanger (24), and is heated. By this heating, the reduced-pressure refrigerant evaporates. The evaporated refrigerant under reduced pressure is diverted, and the flow rate is adjusted when passing through the flow rate adjusting valves (EV3, EV4, EV5). Then, the decompressed refrigerant whose flow rate is adjusted by the flow rate adjusting valves (EV3, EV4, EV5) is injected into the compression chambers at the intermediate pressure positions in the compressors (21a, 21b, 21c).

  On the other hand, the high-pressure refrigerant flowing into the first pipe (93a) of the liquid side connecting pipe flows into the supercooling circuit (10a) from the first end (18a) of the supercooling circuit (10a), and then It flows into the 2nd high temperature side flow path (15a) of the said 2nd subcooling heat exchanger (15) through 2 connection piping (19a). The high-pressure refrigerant flowing into the second high-temperature side flow path (15a) was cooled by releasing heat to the intermediate-pressure refrigerant flowing through the second low-temperature side flow path (15b) of the second supercooling heat exchanger (15). Then, it flows out out of the second high temperature side channel (15a). This cooling increases the degree of supercooling of the high-pressure refrigerant.

  The high-pressure refrigerant that has flowed out of the second high-temperature channel (15a) passes through the third end (18c) of the supercooling circuit (10a) and flows out of the supercooling circuit (10a), and then the liquid side After passing through the second pipe (93b) of the connecting pipe, it again flows into the supercooling circuit (10a) from the second end (18b) of the supercooling circuit (10a).

  The high-pressure refrigerant that has flowed into the supercooling circuit (10a) flows into the first high-temperature channel (14a) of the first supercooling heat exchanger (14) through the first connection pipe (19b). After the high-pressure refrigerant flowing into the first high-temperature side channel (14a) is cooled by releasing heat to the low-pressure refrigerant flowing through the first low-temperature side channel (14b) of the first supercooling heat exchanger (14). The first high temperature side flow path (14a) flows out. This cooling further increases the degree of supercooling of the high-pressure refrigerant. The high-pressure refrigerant that has flowed out of the first high-temperature channel (14a) passes through the fourth end (18d) of the supercooling circuit (10a) and flows out of the supercooling circuit (10a), and then the liquid side It flows into the third pipe (93c) of the connecting pipe.

  The high-pressure refrigerant that has flowed into the third pipe (93c) of the liquid side connection pipe is divided and one flows from the liquid end (65) of the refrigeration circuit (60a) into the refrigeration circuit (60a) and the other is It flows into the freezing circuit (70a) from the freezing liquid side closing valve (85) of the freezing circuit (70a). In addition, since the flow of the refrigerant in the refrigeration circuit (60a) and the refrigeration circuit (70a) is the same as that of the refrigeration apparatus according to the first embodiment, the description thereof is omitted.

  After the low-pressure refrigerant that has flowed out of the refrigeration circuit (60a) and the low-pressure refrigerant that has flowed out of the refrigeration circuit (70a) merge in the gas side connection pipe (92), the low-pressure refrigerant after the merged ) Flows into the outdoor circuit (20a) from the gas side closing valve (43b). The low-pressure refrigerant flowing in from the gas-side closing valve (43a) passes through the first refrigerant pipe (41) and the first four-way switching valve (26a), and then passes from the suction junction pipe (40) to each compressor ( 21a, 21b, 21c). The low-pressure refrigerant sucked into each of the compressors (21a, 21b, 21c) is compressed to a predetermined pressure while the intermediate-pressure refrigerant is injected from the intermediate port during the compression, and becomes a high-pressure refrigerant. (21a, 21b, 21c) is discharged again.

  As described above, in the refrigeration apparatus of the second embodiment, the refrigerant circulates through the refrigerant circuit (1), whereby the cooling operation is performed. The refrigeration unit (60) cools the inside of the refrigeration warehouse, and the refrigeration unit (70 ) To cool the inside of the freezer warehouse.

  When the first four-way selector valve (26a) is set from the first state to the second state, the refrigerant circulation direction is reversed. Thereby, reverse cycle defrost operation is also possible.

-Effect of Embodiment 2-
According to the second embodiment, after the high-pressure refrigerant in the liquid side connecting pipe (93a, 93b, 93c) is cooled by the intermediate pressure refrigerant in the second subcooling heat exchanger (15), It becomes possible to further cool with the low-pressure refrigerant of the first supercooling heat exchanger (14) having a low evaporation temperature.

  If the high-pressure refrigerant flowing through the liquid side communication pipes (93a, 93b, 93c) is first cooled by the low-pressure refrigerant of the first subcooling heat exchanger (14), the first subcooling heat exchanger ( If the amount of heat exchange in 14) is too large, the outlet temperature of the high-pressure refrigerant that has flowed out of the first high-temperature side channel (14a) of the first subcooling heat exchanger (14) may evaporate the intermediate-pressure refrigerant. May be less than temperature. Then, the high pressure refrigerant is not cooled by the second subcooling heat exchanger (15).

  However, according to the second embodiment, the high-pressure refrigerant in the liquid side connection pipes (93a, 93b, 93c) is used as the evaporation temperature of the intermediate-pressure refrigerant and the low-pressure refrigerant in the supercooling circuit (10a). Can be efficiently cooled step by step in descending order.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a refrigeration apparatus including a refrigerant circuit that performs a vapor compression refrigeration cycle and a supercooling circuit that supercools high-pressure refrigerant flowing through the refrigerant circuit.

2 is a refrigerant circuit diagram of the refrigeration apparatus according to Embodiment 1. FIG. 3 is a refrigerant circuit diagram of a supercooling unit of the refrigeration apparatus according to Embodiment 1. FIG. It is a refrigerant circuit figure of the supercooling unit concerning the modification 1 of this Embodiment 1. It is a refrigerant circuit figure of the subcooling unit concerning the modification 2 of this Embodiment 1. FIG. 6 is a refrigerant circuit diagram of a refrigeration apparatus according to Embodiment 2. It is a refrigerant circuit figure of the supercooling unit of the refrigerating device concerning this Embodiment 2.

Explanation of symbols

1 Refrigerant circuit
4 14th refrigerant piping (low pressure line)
5 15th refrigerant pipe (intermediate pressure line)
7a 12th refrigerant pipe (low pressure line)
7b 13th refrigerant pipe (intermediate pressure line)
10 Supercooling unit
10a Supercooling circuit
11 Supercooling compressor
14 First supercooling heat exchanger
15 Second undercooling heat exchanger
20 outdoor unit
50 indoor units
60 Refrigerated showcase
70 frozen showcase

Claims (8)

The use side circuit (50a, 60a, 70a) having the use side heat exchanger (52, 62, 72) in the heat source side circuit (20a) having the compressor for the heat source (21) is connected to the liquid side connecting pipe (80b, 80d, 80a, 80c) and a refrigerant circuit (1) connected to the gas side connecting pipe (92,95) to perform a vapor compression refrigeration cycle, a supercooling compressor (11), and a supercooling expansion valve (EV1) And a supercooling circuit (10a) for performing a vapor compression refrigeration cycle connected to the refrigeration apparatus,
The supercooling circuit (10a) includes an intermediate pressure expansion valve (EV2) connected to the branch pipe (3a) branched from the high pressure liquid line (3) of the supercooling circuit (10a) and the compressor for supercooling. An intermediate pressure line (7b, 5) connecting the intermediate port provided to open to the compression chamber at the intermediate pressure position in (11);
The first high temperature side channel (14a) has a first low temperature side channel (14b) and a first high temperature side channel (14a), and is connected to the liquid side connecting pipe (80b, 80d, 80a, 80c). And a first supercooling heat exchanger (14) in which the first low temperature side flow path (14b) is connected to the low pressure line (7a, 4) of the supercooling circuit (10a);
The second high temperature side channel (15a) has a second low temperature side channel (15b) and a second high temperature side channel (15a) and is connected to the liquid side connection pipe (80b, 80d, 80a, 80c). And a second subcooling heat exchanger (15) in which the second low temperature side flow path (15b) is connected to the intermediate pressure line (7b, 5) of the supercooling circuit (10a). A refrigeration apparatus characterized by that. In claim 1,
The usage side circuit (50a, 60a, 70a) includes a first usage side circuit (60a, 70a) and a second usage side circuit (50a) arranged in parallel to the heat source side circuit (20a),
In the first liquid side connecting pipe (80b, 80d) as the liquid side connecting pipe connecting the heat source side circuit (20a) and the first usage side circuit (60a, 70a), the first subcooling heat exchanger is provided. The first high temperature side flow path (14a) of (14) is connected;
In the second liquid side connection pipe (80a, 80c) as the liquid side connection pipe connecting the heat source side circuit (20a) and the second usage side circuit (50a), the second subcooling heat exchanger (15 The second high temperature side flow path (15a) is connected to the refrigeration apparatus. In claim 2,
The use side heat exchanger of the first use side circuit (60a, 70a) is composed of a cooling heat exchanger (62, 72) for cooling the inside of the cabinet,
The use side heat exchanger of the second use side circuit (50a) is composed of an air conditioning heat exchanger (52) for air-conditioning the room. In claim 2 or 3,
Having the third low temperature side channel (16b) and the third high temperature side channel (16a), the third low temperature side channel (16b) is connected to the low pressure line (7a, 4) of the supercooling circuit (10a). The third high temperature side flow path (16a) is connected to the second utilization side circuit (50a) side of the second high temperature side flow path (15a) of the second subcooling heat exchanger (15). A refrigeration apparatus comprising a third subcooling heat exchanger (16) connected to the second liquid side connecting pipe (80a, 80c) as described above. In claim 4,
The second liquid side connecting pipe (80a, 80c) includes a bypass channel (81) for bypassing the third high temperature side channel (16a) of the third supercooling heat exchanger (16), and the bypass flow. A refrigeration apparatus comprising a first on-off valve (82) for opening and closing the passage (81). In any one of claims 2 to 5,
The fourth low temperature side channel (91b) has a fourth low temperature side channel (91b) and a fourth high temperature side channel (91a), and the fourth low temperature side channel (91b) is an intermediate pressure line (7b, 5) of the supercooling circuit (10a). And the fourth high temperature side channel (91a) is positioned closer to the heat source side circuit (20a) than the first high temperature side channel (14a) of the first subcooling heat exchanger (14). A refrigeration apparatus comprising a fourth subcooling heat exchanger (91) connected to the first liquid side connecting pipe (80b, 80d). In claim 1,
The first high temperature side flow path (14a) of the first subcooling heat exchanger (14) has a use side circuit (more than the second high temperature side flow path (15a) of the second subcooling heat exchanger (15) ( A refrigeration apparatus connected to the liquid side connecting pipe (80b, 80d, 80a, 80c) so as to be located on the side of 50a, 60a, 70a). In any one of Claims 1-7,
The communication passage (6) connecting the intermediate pressure line (7b, 5) and the low pressure line (7a, 4) of the supercooling circuit (10a) has a second on-off valve (opening and closing) for opening and closing the communication passage (6). SV2) is provided.

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