EP4650691A1

EP4650691A1 - Heat source unit and refrigeration device

Info

Publication number: EP4650691A1
Application number: EP25734550.4A
Authority: EP
Inventors: Masaaki Takegami; Naoto Kimura; Takuma Hashimoto
Original assignee: Daikin Industries Ltd
Current assignee: Daikin Industries Ltd
Priority date: 2024-03-25
Filing date: 2025-02-27
Publication date: 2025-11-19
Also published as: EP4650691A4; JP2025147900A; WO2025204473A1

Abstract

A heat source unit constitutes a refrigeration apparatus (1) including a showcase (50). The showcase (50) includes a first utilization heat exchanger (54) connected to a refrigerant circuit (11). The heat source unit includes: a compression element (21, 22, 23), a first decompression mechanism (14), and a heat source heat exchanger (13) connected to the refrigerant circuit (11); a detector (90) configured to detect a business status of a store including the showcase (50); and a control unit (C1) configured to control operation of the refrigeration apparatus (1). The control unit (C1) executes a first operation that limits the operation of the refrigeration apparatus (1) if it is detected that the store is outside business hours.

Description

TECHNICAL FIELD

The present disclosure relates to a heat source unit and a refrigeration apparatus.

BACKGROUND ART

In a store such as a grocery store, foods and beverages in a showcase are refrigerated or frozen by a refrigeration apparatus. Patent Document 1 discloses a control method for controlling the capacity of a refrigeration apparatus in accordance with the cooling load of a showcase.

CITATION LIST

PATENT DOCUMENT

Patent Document 1: Japanese Unexamined Patent Publication No. 2018-4146

SUMMARY OF THE INVENTION

TECHNICAL PROBLEM

To continue refrigerating or freezing foods and beverages in a showcase, a refrigeration apparatus needs to be in operation all day. Unfortunately, even though no customers visit the store outside of business hours, if the inside of the showcases continues to be cooled at a load equivalent to that during business hours of the store, it is not possible to reduce power consumption.
It is an object of the present disclosure to achieve energy conservation in refrigeration apparatuses outside business hours of stores.

SOLUTION TO THE PROBLEM

A first aspect is directed to a heat source unit constituting a refrigeration apparatus (1). The refrigeration apparatus (1) includes at least one showcase (50). The at least one showcase (50) includes a first utilization heat exchanger (54) connected to a refrigerant circuit (11). The heat source unit includes: a compression element (21, 22, 23), a first decompression mechanism (14), and a heat source heat exchanger (13) connected to the refrigerant circuit (11); a detector (90) configured to detect a business status of a store including the at least one showcase (50); and a control unit (C1) configured to control operation of the refrigeration apparatus (1). The control unit (C1, C3) executes a first operation that limits the operation of the refrigeration apparatus (1) if the store is detected to be outside business hours.
According to the first aspect, the first operation restricts operation of the refrigeration apparatus (1) outside business hours, thus achieving energy conservation. In particular, foods or beverages that can be stored at room temperature do not need to be refrigerated outside business hours. Thus, the first operation can contribute to energy conservation of the refrigeration apparatus (1).
A second aspect is an embodiment of the first aspect. In the second aspect, the first operation is an operation in which a duration of a thermostat off mode of the refrigeration apparatus (1) is longer than a duration of the thermostat off mode during business hours of the store.
According to the second aspect, the duration of the thermostat off mode that limits operation of the compression element (21, 22, 23) outside business hours is longer than that during business hours, thus achieving energy conservation of the refrigeration apparatus (1). The first operation is executed, in particular, for the products that do not need to be refrigerated or frozen. The reason for this is that while increasing the standby time in the thermostat off mode is more likely to trigger an increase in the internal temperature of the showcase (50), the products that do not need to be refrigerated or frozen are not affected.
A third aspect is an embodiment of the first or second aspect. In the third aspect, the control unit (C1, C3) sets a first temperature at which a thermostat off mode of the refrigeration apparatus (1) ends in the first operation to be higher than the first temperature during business hours of the store.
According to the third aspect, if the temperature at which switching is made from the thermostat off mode to the thermostat on mode outside business hours is set to be higher than that during business hours, the time during which operation of the compression element (21, 22, 23) is limited can be increased.
A fourth aspect is an embodiment of any one of the first to third aspects. In the fourth aspect, in the first operation, the control unit (C1, C3) sets a target evaporation temperature of a refrigerant in the first utilization heat exchanger (54) to be higher than the target evaporation temperature of the refrigerant in the first utilization heat exchanger (54) during business hours of the store.
According to the fourth aspect, the difference between the evaporation temperature and the target evaporation temperature in the first utilization heat exchanger (54) is smaller outside business hours than during business hours. This makes it difficult for the number of revolutions of the compression element (21, 22, 23) to increase. Thus, energy conservation of the refrigeration apparatus (1) can be achieved.
A fifth aspect is an embodiment of any one of the first to fourth aspects. In the fifth aspect, the first operation is an operation in which a rate of increase in an operation frequency of the compression element (21, 22, 23) is lower than a rate of increase in the operation frequency of the compression element (21, 22, 23) during business hours of the store (T).
According to the fifth aspect, the operation frequency of the compression element (21, 22, 23) increases more gently outside business hours than during business hours, thus achieving energy conservation of the refrigeration apparatus (1).
A sixth aspect of the present disclosure is an embodiment of any one of the first to fifth aspects. In the sixth aspect, when it is detected that the store (T) has entered business hours, the control unit (C1, C3) is prevented from executing the first operation.
According to the sixth aspect, the first operation can be prevented from being executed during business hours of the store.
A seventh aspect is an embodiment of any one of the first to sixth aspects. In the seventh aspect, the detector (90) detects that a first member (59) that restricts a change in air temperature in the at least one showcase (50) has been attached to the at least one showcase (50), and if it is detected that the first member (59) has been attached to the at least one showcase (50), the control unit (C1, C3) determines that the store (T) is detected to be outside business hours.
According to the seventh aspect, attaching the first member (59) to the showcase (50) allows the first operation to be executed for the products that need to be refrigerated or frozen. If the attachment of the first member (59) is detected, the first operation can be automatically executed.
An eighth aspect is an embodiment of any one of the first to seventh aspects. In the eighth aspect, the refrigeration apparatus (1) includes the multiple showcases (50), and the control unit (C1, C3) executes the first operation for a target one of the multiple showcases (50).
According to the eighth aspect, the first operation can be executed only for a target one of the showcases (50). This is useful if the storage temperature of products varies among the showcases.
A ninth aspect is directed to a refrigeration apparatus including: the heat source unit (10) of any one of the first to eighth aspects; and the at least one showcase (50).
According to the ninth aspect, the refrigeration apparatus (1) that executes the first operation outside business hours can be provided.
A tenth aspect is an embodiment of the ninth aspect. In the tenth aspect, the at least one showcase (50) includes a transparent panel (70) and a heater (75) configured to reduce fogging of the transparent panel (70), and the control unit (C1, C3) limits operation of the heater (75) in the first operation.
According to the tenth aspect, pausing operation of the heater (75) during the first operation can reduce the power consumption outside business hours. Thus, energy conservation of the refrigeration apparatus (1) can be achieved.
An eleventh aspect is an embodiment of the ninth or tenth aspect. In the eleventh aspect, the at least one showcase (50) includes a second decompression mechanism (53) connected to the refrigerant circuit (11), and the control unit (C1, C3) controls the second decompression mechanism (53) to allow a degree of superheat of a suction refrigerant sucked from the first utilization heat exchanger (54) into the compression element (21, 22, 23) in the first operation to be higher than the degree of superheat before start of the first operation.
According to the eleventh aspect, the second decompression mechanism (53) is narrowed. This makes it difficult for the refrigerant to flow. This suppresses the low pressure, thereby making it difficult for the number of revolutions of the compression element (21, 22, 23) to increase.
A twelfth aspect is an embodiment of any one of the ninth to eleventh aspects. The refrigeration apparatus of the twelfth aspect further includes: an indoor unit (60) configured to condition air in an indoor space in the store (T). The indoor unit (60) includes a second utilization heat exchanger (64) connected to the refrigerant circuit (11), the compression element (21, 22, 23) includes a first compressor (21) configured to compress a refrigerant flowing out of the first utilization heat exchanger (54), and a second compressor (22) configured to compress the refrigerant flowing out of the second utilization heat exchanger (64), and if, in the first operation, adjustment of a temperature in the at least one showcase (50) has priority over air conditioning in the indoor space, the control unit (C1, C3) increases an operation frequency of the first compressor (21).

BRIEF DESCRIPTION OF THE DRAWINGS

[FIG. 1] FIG. 1 is a piping system diagram of a refrigeration apparatus according to an embodiment.
[FIG. 2A] FIG. 2A is a schematic diagram illustrating a configuration of a showcase according to an embodiment.
[FIG. 2B] FIG. 2B is a view corresponding to FIG. 2A, illustrating a state where a cover for the showcase is closed.
[FIG. 3] FIG. 3 is a block diagram showing the relationship between control units for the refrigeration apparatus and devices.
[FIG. 4] FIG. 4 is a piping system diagram corresponding to FIG. 1, illustrating the flow of a refrigerant during a refrigerating operation.
[FIG. 5] FIG. 5 is a piping system diagram corresponding to FIG. 1, illustrating the flow of a refrigerant during a cooling/refrigerating operation.
[FIG. 6] FIG. 6 is a piping system diagram corresponding to FIG. 1, illustrating the flow of a refrigerant during a heating/refrigerating operation.
[FIG. 7] FIG. 7 is a flowchart showing a flow of a first operation.
[FIG. 8] FIG. 8 is a view corresponding to FIG. 2A, illustrating a showcase according to a fourth variation.

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described in detail below with reference to the drawings. The following embodiments are merely exemplary ones in nature, and are not intended to limit the scope, application, or uses of the invention. Features of the embodiments, variations, and other examples described below can be combined or partially substituted within the range where the present invention can be embodied.

(1) Configuration of Refrigeration Apparatus

As illustrated in FIG. 1, a refrigeration apparatus (1) of the present disclosure is used in a store (T) that retails foods and beverages, such as a supermarket. Showcases (50) are arranged in a selling space inside the store (T). The showcases (50) each have products that need to be refrigerated or frozen on display. The multiple showcases (50) are arranged in the store (T).
The refrigeration apparatus (1) includes an outdoor unit (10), an indoor unit (60), and the multiple showcases (50). The outdoor unit (10) is placed outside the store (T). The indoor unit (60) conditions air in an indoor space in the store (T). Each of the showcases (50) cools inside air in the showcase (50). As can be seen, the refrigeration apparatus (1) cools the inside of the showcases (50), and simultaneously conditions air in a space in the store (T).
The refrigeration apparatus (1) includes a refrigerant circuit (11) configured to perform a refrigeration cycle. The outdoor unit (10), the indoor unit (60), and the multiple showcases (50) are connected together through connection pipes (2, 3, 4, 5) forming the refrigerant circuit (11). The multiple showcases (50) are connected in series to the outdoor unit (10).

(2) Outdoor Unit

The outdoor unit (10) is an example of a heat source unit (10). The outdoor unit (10) includes compression elements (21, 22, 23), switching units (TV1, TV2), an outdoor heat exchanger (13), an outdoor expansion valve (14), a gas-liquid separator (15), a cooling heat exchanger (16), and an intercooler (17), which are connected to the refrigerant circuit (11). The outdoor unit (10) includes an outdoor fan (12) and a cooling fan (17a).

(2-1) Compression Element

The compression elements (21, 22, 23) are of a so-called "two-stage compression type." Specifically, the compression elements (21, 22, 23) include a first compressor (21), a second compressor (22), and a third compressor (23). The first compressor (21) and the second compressor (22) each constitute a low-stage compressor, and the third compressor (23) constitutes a high-stage compressor. The refrigerant that has been compressed in, and discharged from, the first compressor (21) is sucked into the third compressor (23) so as to be compressed. The refrigerant that has been compressed in, and discharged from, the second compressor (22) is sucked into the third compressor (23) so as to be compressed.
The first compressor (21) is a compressor associated with the showcases (50). The first compressor (21) compresses the refrigerant flowing out of internal heat exchangers (54), which will be described later. The second compressor (22) is a compressor associated with the indoor unit (60). The second compressor (22) compresses the refrigerant flowing out of an indoor heat exchanger (64), which will be described later.
The first to third compressors (21 to 23) are rotary-type compressors, each of which includes a compression mechanism driven by a motor. The compressors (21 to 23) are variable capacity compressors operating at an adjustable operation frequency or at an adjustable rotational speed. The compressors (21 to 23) are, for example, rotary, scroll, or screw compressors.

(2-2) Switching Unit

The switching units (TV1, TV2) switch the flow path of the refrigerant through the refrigerant circuit (11). The switching units (TV1, TV2) include a first three-way valve (TV1) and a second three-way valve (TV2).
The first three-way valve (TV1) has a first port (P1) connected to a first pipe (31) serving as a high-pressure line, a second port (P2) connected to a third pipe (33) serving as a low-pressure line, and a third port (P3) communicating with an indoor-side gas line (35).
The second three-way valve (TV2) has a first port (P1) connected to a second pipe (32) serving as a high-pressure line, a second port (P2) connected to a fourth pipe (34) serving as a low-pressure line, and a third port (P3) communicating with an outdoor-side gas line (36).
Each of the first three-way valve (TV1) and the second three-way valve (TV2) switches between a first state (the state indicated by the solid curve in FIG. 1) and a second state (the state indicated by the dotted curve in FIG. 1).

(2-3) Outdoor Heat Exchanger

The outdoor heat exchanger (13) is a fin-and-tube air heat exchanger. The outdoor fan (12) transports outdoor air to the outdoor heat exchanger (13). In the outdoor heat exchanger (13), heat exchange occurs between the refrigerant flowing through the outdoor heat exchanger (13) and the outdoor air. The outdoor heat exchanger (13) is an example of a heat source heat exchanger (13).
The gas end of the outdoor heat exchanger (13) is connected to the outdoor-side gas line (36). The liquid end of the outdoor heat exchanger (13) communicates with an outdoor flow path (O).

(2-4) Outdoor Expansion Valve

The outdoor expansion valve (14) is connected to the outdoor flow path (O). The outdoor flow path (O) is located in the outdoor unit (10) and constitutes the refrigerant circuit (11). The outdoor expansion valve (14) decompresses the refrigerant condensed in the outdoor heat exchanger (13). The outdoor expansion valve (14) is an example of a first decompression mechanism (14). The outdoor expansion valve (14) is an electronic expansion valve having a variable opening degree.

(2-5) Gas-Liquid Separator

The gas-liquid separator (15) separates the refrigerant into a gas refrigerant and a liquid refrigerant. The gas-liquid separator (15) is connected to the outdoor flow path (O). A venting pipe (not shown) communicating with an injection flow path (38) is connected to the gas-liquid separator (15).

(2-6) Cooling Heat Exchanger

The cooling heat exchanger (16) cools the refrigerant (mainly the liquid refrigerant) separated in the gas-liquid separator (15). The cooling heat exchanger (16) has a first flow path (16a) and a second flow path (16b). The refrigerant that has flowed out of the gas-liquid separator (15) is split into the first flow path (16a) and the second flow path (16b). The refrigerant that has been decompressed at the decompression valve (40) flows through the second flow path (16b). The refrigerant flowing through the first flow path (16a) exchanges heat with the refrigerant flowing through the second flow path (16b), and is thus cooled.
The second flow path (16b) communicates with the injection flow path (38). The injection flow path (38) is connected to an intermediate-pressure flow path (41) through which the refrigerant of intermediate pressure flows between the low-stage compressors and the high-stage compressor. In other words, the injection flow path (38) is connected to the suction side of the third compressor (23) or to a suction pipe.

(2-7) Intercooler

The intercooler (17) cools the intermediate-pressure refrigerant. The intercooler (17) is connected to the intermediate-pressure flow path (41). The intercooler (17) is provided on the discharge side of the first compressor (21) and the second compressor (22) and on the suction side of the third compressor (23). The intercooler (17) is a fin-and-tube air heat exchanger. The intercooler (17) exchanges heat between the outdoor air transported by the cooling fan (17a) and the refrigerant flowing through the intercooler (17).

(2-8) Check Valve

Seven check valves (CV1 to CV7) are connected to the refrigerant circuit (11). The check valves (CV1 to CV7) allow the refrigerant to flow in the directions indicated by the respective arrows shown in FIG. 1, and restrict the flow of the refrigerant in the directions opposite thereto.

(3) Indoor Unit

The indoor unit (60) includes an indoor expansion valve (63) and an indoor heat exchanger (64), which are connected to the refrigerant circuit (11). The indoor unit (60) includes an indoor fan (62). The indoor expansion valve (63) is an electronic expansion valve having a variable opening degree. The indoor heat exchanger (64) is a fin-and-tube air heat exchanger. The indoor heat exchanger (64) exchanges heat between the indoor air transported by the indoor fan (62) and the refrigerant flowing through the indoor heat exchanger (64). The indoor heat exchanger (64) is an example of a second utilization heat exchanger (64).

(4) Showcase

FIGS. 2A and 2B show an example of a showcase (50). The showcase (50) includes a casing (55), an internal heat exchanger (54), an internal fan (52), an internal expansion valve (53), and a cover (59).
The casing (55) is substantially formed in the shape of a box. The casing (55) has a front surface with an opening (56). The opening (56) is formed in substantially the entire front surface of the casing (55). A partitioning member (57) is provided in the casing (55). The partitioning member (57) partitions an internal space (S) in the casing (55) into a first air passage (A1) and a second air passage (A2). The partitioning member (57) extends, from above, downward near a central portion of the internal space (S) in the forward/backward direction, and then extends forward in a lower portion of the internal space (S).
The first air passage (A1) is formed near the front of the internal space (S). Multiple display shelves (58) are provided in the first air passage (A1). The display shelves (58) are plates on each of which products are placed. The display shelves (58) extend forward from the partitioning member (57). The display shelves (58) may be arranged on the partitioning member (57) in the upward/downward direction and in the rightward/leftward direction.
The second air passage (A2) is formed near the back of the internal space (S). The second air passage (A2) and the first air passage (A1) communicate with each other in an upper portion of the internal space (S). The second air passage (A2) and the first air passage (A1) communicate with each other in the lower portion of the internal space (S). Air flows through the internal space (S) in the directions indicated by the arrows shown in FIG. 2A.
The internal heat exchanger (54), the internal expansion valve (53), and the internal fan (52) are arranged in the second air passage (A2). The internal heat exchanger (54) is an example of a first utilization heat exchanger (54). The internal expansion valve (53) is an example of a second decompression mechanism (53).
The internal heat exchanger (54) is connected to the refrigerant circuit (11). The internal heat exchanger (54) is a fin-and-tube air heat exchanger. The internal fan (52) transports inside air, which is air in the showcase (50), to the internal heat exchanger (54). The internal heat exchanger (54) exchanges heat between the inside air and the refrigerant flowing through the internal heat exchanger (54).
The internal expansion valve (53) is connected to the refrigerant circuit (11). The internal expansion valve (53) is an electronic expansion valve having a variable opening degree.
The cover (59) is a member that opens and closes the opening (56). The cover (59) is an example of a first member (59). The cover (59) is a sheet member having a size large enough to cover the opening (56). The cover (59) may be made of a heat insulating material.
While the cover (59) covers the opening (56), the temperature of the inside air is less likely to increase sharply even with the refrigeration apparatus (1) deactivated. In other words, the cover (59) restricts a change in air temperature in the showcase (50). This reduces an increase in temperature in the showcase (50) even if the capacity of the refrigeration apparatus (1) is lowered. Thus, power consumption of the refrigeration apparatus (1) can be reduced.
The cover (59) is detached from the opening (56) just before or at the opening time of the store or after the start of business hours (FIG. 2A). Specifically, the cover (59) is located at the upper end of the opening (56) while being wound around a support (61) pivotably supported.
The cover (59) is attached to the showcase (50) to cover the opening (56) just before or at the end of the business hours of the store or after the end of the business hours (FIG. 2B). Specifically, the support (61) is rotated so that the cover (59) is stretched downward to cover the opening (56).
As can be seen from above, the cover (59) is attached to the opening (56) of the showcase (50) at the end of the business hours. The cover (59) is detached from the opening (56) of the showcase (50) at the start of the business hours.

(5) Sensor

The refrigeration apparatus (1) includes multiple sensors. The multiple sensors include refrigerant temperature sensors (86), internal temperature sensors (88), and a first sensor (90). The refrigerant temperature sensors (86) and the internal temperature sensors (88) are provided in the associated showcases (50). Each of the refrigerant temperature sensors (86) detects the evaporation temperature of the refrigerant in the associated internal heat exchanger (54). Each of the internal temperature sensors (88) detects the air temperature in the associated showcase (50). The first sensor (90) detects that the covers (59) have been attached to the associated showcases (50). Specifically, the first sensor (90) detects whether the openings (56) have been opened or closed by the associated covers (59). More specifically, the first sensor (90) detects whether the covers (59) have completely covered the associated openings (56). As can be seen from above, the first sensor (90) detects the business status of the store (T). The first sensor (90) is an example of a detector (90).

(6) Remote Controller

As illustrated in FIG. 1, the refrigeration apparatus (1) has a remote controller (100). A user can operate the remote controller (100) to select an operation, such as a cooling operation, a heating operation, or a refrigerant release operation.

(7) Control Unit

As shown in FIG. 3, the refrigeration apparatus (1) includes an outdoor control unit (C1), an indoor control unit (C2), and internal control units (C3). The outdoor control unit (C1), the indoor control unit (C2), and the internal control units (C3) are communicable with one another in a wireless or wired manner. The outdoor control unit (C1) and the internal control units (C3) are examples of the control units (C1, C3).
The outdoor control unit (C1), the indoor control unit (C2), and the internal control units (C3) include a micro controller unit (MCU), an electric circuit, and an electronic circuit. The MCU includes a central processing unit (CPU), a memory, and a communications interface. The memory stores various programs to be executed by the CPU.
The outdoor control unit (C1) is provided in the outdoor unit (10). The outdoor control unit (C1) controls switching between start and stop of the compressor (21), the number of revolutions of the compressor (21), switching between start and stop of the outdoor fan (12), the number of revolutions of the outdoor fan (12), the opening degree of the outdoor expansion valve (14), and other elements in the outdoor unit (10).
The indoor control unit (C2) is provided in the indoor unit (60). The indoor control unit (C2) controls switching between start and stop of the indoor fan (62), the number of revolutions of the indoor fan (62), and other elements.
The internal control units (C3) are provided in the associated showcases (50). Each of the internal control units (C3) controls switching between start and stop of the associated internal fan (52), the number of revolutions of the associated internal fan (52), and other elements.

(8) Operation

An example of operation of the refrigeration apparatus (1) will be described below. In the following description, the showcases (50) execute the refrigerating operation. The indoor unit (60) switches between the cooling operation and the heating operation.

(8-1) Refrigerating Operation

In the cooling operation illustrated in FIG. 4, the first three-way valve (TV1) is in the second state, and the second three-way valve (TV2) is in the first state. The outdoor expansion valve (14) is open at a predetermined opening degree, the opening degree of the internal expansion valves (53) is controlled by superheat control, the indoor expansion valve (63) is fully closed, and the opening degree of the decompression valve (40) is controlled appropriately. The outdoor fan (12) and the internal fans (52) are operated, and the indoor fan (62) is paused. The first compressor (21) and the third compressor (23) are operated, and the second compressor (22) is paused.
The refrigerant compressed in the first compressor (21) is cooled in the intercooler (17), and is then sucked into the third compressor (23). The refrigerant that has been compressed in the third compressor (23) dissipates heat in the outdoor heat exchanger (13), flows through the gas-liquid separator (15), and is then cooled in the first flow path (16a) of the cooling heat exchanger (16). The refrigerant in the second flow path (16b) that has cooled the refrigerant in the first flow path (16a) flows through the injection flow path (38), and is sucked into the third compressor (23). The refrigerant that has been cooled in the first flow path (16a) of the cooling heat exchanger (16) is decompressed in the internal expansion valves (53), and then evaporates in the internal heat exchangers (54). Thus, the inside air in the showcases (50) is cooled. The refrigerant that has evaporated in the cooling heat exchanger (16) is sucked into the first compressor (21), and is then compressed again.

(8-2) Cooling/Refrigerating Operation

In the cooling/refrigerating operation illustrated in FIG. 5, the first three-way valve (TV1) is in the second state, and the second three-way valve (TV2) is in the first state. The outdoor expansion valve (14) is open at a predetermined opening degree, the opening degrees of the internal expansion valves (53) and the indoor expansion valve (63) are controlled by superheat control, and the opening degree of the decompression valve (40) is controlled appropriately. The outdoor fan (12), the internal fans (52), and the indoor fan (62) are operated. The first compressor (21), the second compressor (22), and the third compressor (23) are operated.
The refrigerant that has been compressed in the first compressor (21) and the refrigerant that has been compressed in the second compressor (22) are sucked into the third compressor (23). The refrigerant that has been compressed in the third compressor (23) dissipates heat in the outdoor heat exchanger (13), flows through the gas-liquid separator (15), and is then cooled in the first flow path (16a) of the cooling heat exchanger (16). The refrigerant in the second flow path (16b) that has cooled the refrigerant in the first flow path (16a) flows through the injection flow path (38), and is sucked into the third compressor (23).
The refrigerant that has been cooled in the first flow path (16a) of the cooling heat exchanger (16) diverges into the showcases (50) and the indoor unit (60). The refrigerant that has been decompressed in the internal expansion valves (53) evaporates in the associated internal heat exchangers (54). The refrigerant that has evaporated in the internal heat exchangers (54) is sucked into the first compressor (21), and is then compressed again. The refrigerant that has been decompressed in the indoor expansion valve (63) evaporates in the indoor heat exchanger (64). The refrigerant that has evaporated in the indoor heat exchanger (64) is sucked into the second compressor (22), and is then compressed again.

(8-3) Heating/Refrigerating Operation

In the heating/refrigerating operation illustrated in FIG. 6, the first three-way valve (TV1) is in the first state, and the second three-way valve (TV2) is in the second state. The indoor expansion valve (63) is open at a predetermined opening degree, the opening degrees of the internal expansion valves (53) and the outdoor expansion valve (14) are controlled by superheat control, and the opening degree of the decompression valve (40) is controlled appropriately.
The outdoor fan (12), the internal fans (52), and the indoor fan (62) are operated. The first compressor (21), the second compressor (22), and the third compressor (23) are operated.
The refrigerant that has been compressed in the first compressor (21) and the refrigerant that has been compressed in the second compressor (22) are sucked into the third compressor (23). The refrigerant that has been compressed in the third compressor (23) dissipates heat in the indoor heat exchanger (64). Thus, the indoor air is heated. The refrigerant that has dissipated heat in the indoor heat exchanger (64) flows through the gas-liquid separator (15), and is then cooled in the first flow path (16a) of the cooling heat exchanger (16). The refrigerant in the second flow path (16b) that has cooled the refrigerant in the first flow path (16a) flows through the injection flow path (38), and is sucked into the third compressor (23). Part of the refrigerant that has been cooled in the first flow path (16a) of the cooling heat exchanger (16) is decompressed in the outdoor expansion valve (14), and then evaporates in the outdoor heat exchanger (13). The refrigerant that has evaporated in the outdoor heat exchanger (13) is sucked into the second compressor (22), and is then compressed again.
The rest of the refrigerant that has been cooled in the first flow path (16a) of the cooling heat exchanger (16) is decompressed in the internal expansion valves (53), and then evaporates in the internal heat exchangers (54). Thus, the inside air is cooled. The refrigerant that has evaporated in the internal heat exchangers (54) is sucked into the first compressor (21), and is then compressed again.

(9) First Operation

If it is detected that the store (T) is outside business hours of the store (T), the outdoor control unit (C1) executes a first operation that limits operation of the refrigeration apparatus (1). The first operation includes an outdoor first operation to be executed in the outdoor unit (10) and an internal first operation to be executed in the showcases (50).

(9-1) Outdoor First Operation

The outdoor first operation is an operation in which the duration of a thermostat off mode of the refrigeration apparatus (1) is longer than the duration of the thermostat off mode during business hours of the store (T).
Specifically, the refrigeration apparatus (1) alternately repeats the thermostat off mode and the thermostat on mode at about a set temperature in the showcases (50). When the internal temperature of the showcases (50) falls below a predetermined temperature lower than the set temperature, the thermostat off mode is executed. In the thermostat off mode, operations of the first compressor (21) and the third compressor (23) are restricted, or are temporarily paused. The thermostat off mode is continued for a fixed period. For example, the duration of the thermostat off mode to be executed outside business hours is three minutes, and the duration of the thermostat off mode to be executed during business hours is set to be one minute. In this manner, lengthening the duration of the thermostat off mode reduces power consumption of the compression elements (21 to 23).

(9-2) Internal First Operation

The internal first operation is an operation in which the internal expansion valves (53) are controlled to allow the degree of superheat of a suction refrigerant sucked from the internal heat exchangers (54) into the first compressor (21) to be higher than the degree of superheat during business hours. In other words, in the internal first operation, the opening degree of the internal expansion valves (53) outside business hours is lower than the opening degree of the internal expansion valves (53) during business hours. Thus, reducing the amount of circulation of the refrigerant triggers a reduction in the amount of the suction refrigerant to be sucked into the first compressor (21).

(10) Action of Control Unit

An example of an action of the control unit (C1) in the first operation will be described with reference to FIG. 7. In the following example, air in the store (T) is not conditioned outside business hours of the store (T). That is to say, the indoor unit (60) is deactivated outside business hours. In other words, the refrigerating operation is executed outside business hours.
In step S01, the outdoor control unit (C1) determines whether or not business hours of the store (T) have ended (whether or not the store (T) is outside business hours). Specifically, the outdoor control unit (C1) determines whether or not a first signal indicating that the covers (59) have covered the associated openings (56) has been received from the first sensor (90).
In step S02, the outdoor control unit (C1) determines whether or not all of the showcases (50) are targets for the first operation. For example, the showcases (50) displaying products, such as frozon products or perishables, need to be maintained at a constant temperature all day to maintain quality. Such showcases (50) are not suitable for execution of the first operation. Thus, the outdoor control unit (C1) determines the presence or absence of a showcase (50) that is not suitable for execution of the first operation, and if the showcase (50) that is not suitable for execution of the first operation is present, this showcase (50) is identified. For example, a unique identifier (ID) is assigned to each showcase (50), and the outdoor control unit (C1) identifies the ID of the showcase (50) linked with prohibition of the first operation out of all of the IDs.
If it is determined that all of the showcases (50) are targets for the first operation ("YES" in step S02), step S03 is executed. If it is determined that all of the showcases (50) are not targets for the first operation ("NO" in step S02), step S06 is executed.
In step S03, the outdoor control unit (C1) executes the outdoor first operation. Thus, the duration of the thermostat off mode is longer than the duration of the thermostat off mode during business hours.
In step S04, the outdoor control unit (C1) transmits an instruction to execute the internal first operation to the internal control unit (C3).
In step S05, the internal control unit (C3) executes the internal first operation. Thus, the opening degree of the internal expansion valves (53) is lower than the opening degree of the internal expansion valves (53) during business hours. Specifically, the internal control unit (C3) controls the internal expansion valves (53) so that the opening degree of the internal expansion valves (53) is lowest.
In step S06, the outdoor control unit (C1) determines the presence or absence of the showcase (50) serving as a target for the first operation. If it is determined that the showcase (50) serving as the target for the first operation is present ("YES" in step S06), step S07 is executed. If it is a determined that the showcase (50) serving as the target for the first operation is absent ("NO" in step S06), the first operation is not executed, and this flow ends.
In step S07, the outdoor control unit (C1) transmits an instruction to execute the internal first operation to the internal control unit (C3) for the showcase (50) serving as the target for the first operation.
In step S08, the outdoor control unit (C1) determines whether or not the store (T) has entered business hours (whether or not the store (T) is within business hours). Specifically, the outdoor control unit (C1) determines whether or not reception of the first signal indicating that the covers (59) have covered the associated openings (56) has been ceased. If it is determined that the store (T) has entered business hours ("YES" in step S08), step S09 is executed. If it is determined that the business hours of the store (T) have not been started ("NO" in step S08), step S08 is again executed.
In step S09, the outdoor control unit (C1) stops the first operation. As can be seen from above, the outdoor control unit (C1) is prevented from executing the first operation when it is detected that the store (T) has entered business hours. In other words, the outdoor control unit (C1) does not execute the first operation during business hours of the store (T).

(11) Features

(11-1) Feature 1

The outdoor unit (10) of this embodiment includes the first sensor (90) configured to detect the business status of the store (T). If it is detected that the store (T) has entered outside business hours, the outdoor control unit (C1) executes the first operation that limits operation of the refrigeration apparatus (1).
The first operation restricts operation of the refrigeration apparatus (1) outside business hours, thus achieving energy conservation. In particular, foods or beverages that can be stored at room temperature do not need to be refrigerated outside business hours. Thus, the first operation can contribute to energy conservation of the refrigeration apparatus (1).

(11-2) Feature 2

The first operation of this embodiment is an operation in which the duration of the thermostat off mode of the refrigeration apparatus (1) is longer than the duration of the thermostat off mode during business hours of the store (T).
Such a longer standby time in the thermostat off mode outside business hours lengthens the time during which operations of the first compressor (21) and the third compressor (23) are limited. Thus, energy conservation of the refrigeration apparatus (1) can be achieved. The first operation is executed, in particular, for the products that do not need to be refrigerated or frozen. While increasing the duration of the thermostat off mode is more likely to trigger an increase in the internal temperature of each showcase (50), the quality of the products that do not need to be refrigerated or frozen is less likely to be affected.

(11-3) Feature 3

The outdoor control unit (C1) of this embodiment is prevented from executing the first operation when it is detected that the store (T) is outside business hours. As can be seen from above, the first operation is not executed during business hours of the store (T). This can reduce an increase in the temperature of the products that have been refrigerated or frozen in the showcases (50).

(11-4) Feature 4

The outdoor control unit (C1) of this embodiment controls the internal expansion valves (53) to allow the degree of superheat of the suction refrigerant sucked from the internal heat exchangers (54) into the first compressor (21) in the first operation to be higher than the degree of superheat before the start of the first operation. In other words, the outdoor control unit (C1) sets the opening degree of the internal expansion valves (53) in the first operation to be lower than that before the start of the first operation. Thus, reducing the amount of circulation of the refrigerant triggers a reduction in the amount of the suction refrigerant to be sucked into the first compressor (21). As a result, the number of revolutions of the first compressor (21) and in turn the number of revolutions of the third compressor (23) can be reduced.

(11-5) Feature 5

The first sensor (90) of this embodiment detects that the covers (59) that restrict a change in the air temperature in the associated showcases (50) have been attached to the showcases (50). If it is detected that the covers (59) have been attached to the associated showcases (50), the outdoor control unit (C1) determines that the store (T) has entered outside business hours.
The covers (59) are attached to the openings (56) of the associated showcases (50) at the end of the business hours. Thus, if the first sensor (90) detects that the covers (59) have been attached to the associated showcases (50), it can be determined that the store (T) has entered outside business hours. This enables automatic execution of the first operation.

(12) Variations

Variations of the refrigeration apparatus (1) of the present disclosure will be described. Configurations different from those of the refrigeration apparatus (1) of the foregoing embodiments will be described below.

(12-1) First Variation

An outdoor first operation of a first variation is distinct from the outdoor first operation of the foregoing embodiments. In the outdoor first operation of the first variation, the outdoor control unit (C1) sets the target evaporation temperature of the refrigerant in the internal heat exchanger (54) to be higher than the target evaporation temperature of the refrigerant in the internal heat exchanger (54) before the detection of the store (T) entering outside business hours.
In other words, the outdoor control unit (C1) sets the target evaporation temperature of the refrigerant in each internal heat exchanger (54) after the start of the first operation to be higher than that before the start of the first operation (before the end of the business hours). For example, if the target evaporation temperature in the internal heat exchanger (54) during the business hours is -10°C, the target evaporation temperature in the internal heat exchanger (54) during the first operation is set to be 0°C.
Thus, the difference between the evaporation temperature and the target evaporation temperature in the internal heat exchanger (54) of the showcase (50) is smaller outside business hours than during business hours. This reduces an increase in the number of revolutions of the first compressor (21) during the first operation. Thus, energy conservation of the refrigeration apparatus (1) can be achieved.

(12-2) Second Variation

An outdoor first operation of a second variation is distinct from the outdoor first operation of the foregoing embodiments. The outdoor first operation of the second variation is an operation in which the rate of increase in the operation frequency of the compression elements (21, 22, 23) is lower than the rate of increase in the operation frequency of the compression elements (21, 22, 23) during the business hours of the store (T). In other words, the outdoor control unit (C1) allows the rate of increase in the operation frequency of the compression elements (21, 22, 23) in the first operation to be lower than the rate of increase in the operation frequency of the compression elements (21, 22, 23) before the start of the first operation. Thus, the operation frequency of the compression elements (21, 22, 23) increases more gently outside business hours than during business hours, thus achieving energy conservation of the refrigeration apparatus (1). The compression elements (21, 22, 23) as used herein are the first compressor (21) and the third compressor (23) associated with the internal heat exchangers (54).

(12-3) Third Variation

An outdoor first operation of a third variation is distinct from the outdoor first operation of the foregoing embodiments. The outdoor control unit (C1) of the third variation sets a first temperature at which the thermostat off mode of the refrigeration apparatus (1) ends in the first operation to be higher than the first temperature before detection of the closing of the store (T). In other words, the outdoor control unit (C1) sets the first temperature at which switching is made from the thermostat off mode to the thermostat on mode during the first operation to be higher than the first temperature before the start of the first operation.
If the temperature at which switching is made from the thermostat off mode to the thermostat on mode outside business hours is set to be higher than that during business hours, the time during which operations of the first compressor (21) and the third compressor (23) associated with the internal heat exchangers (54) are limited can be increased.

(12-4) Fourth Variation

An internal first operation of a fourth variation corresponds to control that lowers heat generated by a heater (75) configured to reduce fogging of a door (70) of each showcase (50).
Specifically, as illustrated in FIG. 8, each of showcases (50) has the door (70) with transparent glass. The door (70) is an example of a transparent panel (70). The door (70) is provided at the front surface of the casing (55). The door (70) is provided to be able to open and close the opening (56) of the casing (55). A glass portion of the door (70) forms substantially the entire region of the door (70). Thus, even while the door (70) is closed, products located in the showcase (50) are visible from outside.
The showcase (50) is provided with the heater (75) configured to reduce fogging of the door (70). The heater (75) heats the door (70). This reduces fogging of the door (70) caused by the temperature difference between the inside and outside of the showcase (50).
The outdoor control unit (C1) of the outdoor unit (10) controls operation of the heater (75). The outdoor control unit (C1) operates the heater (75) during the business hours of the store (T). If it is detected that the store (T) is outside business hours, the outdoor control unit (C1) limits operation of the heater (75). In other words, the outdoor control unit (C1) limits the operation of the heater (75) in the first operation. Specifically, the outdoor control unit (C1) may stop operation of the heater (75), or may reduce the amount of heat generated by the heater (75) during the first operation as compared to before the first operation.

(13) Other Embodiments

The foregoing embodiments and variations may also be configured as follows.
The detector (90) of the present disclosure is sufficient to detect that the store (T) has been closed or has entered business hours. For example, the detector (90) may detect that the lights of the store (T) have been turned off or that a door for an entrance of the store (T) has been locked. The first sensor (90) may detect the presence or absence of a person in the store (T). In this case, the detection may be performed on a video of the inside of the store (T) captured by a camera located in the store (T). The detector (90) may detect the opening time and the closing time of the store (T). The detector (90) may detect a signal indicating the start of policing in the store (T) during the night and during holidays.
In step S02 of the first operation of the foregoing embodiments, the outdoor control unit (C1) may determine whether or not a showcase (50) displaying products on display is a target for the first operation, based on the type of the products. The type of the products may be determined on an image captured by a camera or by a bar code assigned to the products.
The refrigeration apparatus (1) may include a communication controller (not shown) located outside the refrigeration apparatus (1). The communication controller is communicably connected to the outdoor control unit (C1) and the internal control unit (C3) of the refrigeration apparatus (1). The communication controller may execute step S02 and step S06 in the first operation, for example.
In the outdoor first operation, at least one of the outdoor first operations described in the foregoing embodiments or the outdoor first operations described in the variations merely needs to be executed. Several of the outdoor first operations described in the foregoing embodiments and the outdoor first operations described in the variations may be combined together.
If all of the showcases (50) are targets for the first operation, only the outdoor first operation or only the internal first operation in the first operation may be executed.
The outdoor control unit (C1) may execute an internal first operation. That is to say, in the flow of the first operation, step S05 and step S07 may be executed by the outdoor control unit (C1).
In the first operation, an action may be performed to fully close the internal expansion valves (53) of the showcases (50) serving as targets for the first operation. Thus, the refrigerant flows through the showcases (50) which are not the targets for the first operation, and the refrigerant does not flow through the showcases (50) serving as the targets for the first operation.
If, in the first operation, adjustment of the internal temperature of the showcases (50) has priority over air conditioning in the store (T), the outdoor control unit (C1) may increase the operation frequency of the second compressor (22) in the first operation. The air-conditioning load in the store (T) is relatively low outside the business hours. Thus, if it is detected that the store (T) has entered outside business hours, the operation frequency of the first compressor (21) may be increased. In particular, if it is detected that the store (T) has entered outside business hours, the air conditioning capacity of the indoor unit (60) is made lower than that during the business hours, thereby reducing the power consumption of the refrigeration apparatus (1) outside business hours.
In the flow of the first operation of the foregoing embodiments, the indoor unit (60) may be operated. That is to say, during the first operation, the cooling operation or the heating operation may be performed. In this case, the second compressor (22) may serve as a target for the first operation.
The refrigeration apparatus of the foregoing embodiments does not need to include the indoor unit (60). In this case, the refrigeration apparatus (1) may be of a single-stage compression type or of a two-stage compression type. In the case of the single-stage compression type, the compression elements (21, 22, 23) include a first compressor (21).
In the outdoor first operation of the foregoing embodiment, the number of revolutions of either the first compressor (21) or the third compressor (23) may be controlled so as to be reduced.
The refrigerant circuit (11) of the foregoing embodiments may have a bypass flow path (not shown) bypassing the third compressor (23). In this case, the bypass flow path connects the suction pipe and the discharge pipe of the third compressor (23) together. In such a refrigerant circuit (11), pausing the third compressor (23) enables switching to the single-stage compression. In the single-stage compression, the number of revolutions of the first compressor (21) may be controlled in the outdoor first operation.
While the embodiments and variations thereof have been described above, it will be understood that various changes in form and details may be made without departing from the spirit and scope of the claims. The foregoing embodiments and variations thereof may be combined and replaced with each other without deteriorating the intended functions of the present disclosure. The expressions of "first," "second," . . . described above are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.

INDUSTRIAL APPLICABILITY

As can be seen from the foregoing description, the present disclosure is useful for a heat source unit and a refrigeration apparatus.

DESCRIPTION OF REFERENCE CHARACTERS

1: Refrigeration Apparatus
10: Outdoor Unit (Heat Source Unit)
11: Refrigerant Circuit
13: Outdoor Heat Exchanger (Heat Source Heat Exchanger)
14: Outdoor Expansion Valve (First Decompression Mechanism)
21: First Compressor
21, 22, 23: Compression Element
22: Second Compressor
50: Showcase
53: Internal Expansion Valve (Second Decompression Mechanism)
54: Internal Heat Exchanger (First Utilization Heat Exchanger)
59: Cover (First Member)
60: Indoor Unit
64: Indoor Heat Exchanger (Second Utilization Heat Exchanger)
75: Heater
90: First Sensor (Detector)
C1: Outdoor Control Unit (Control Unit)
T: Store

Claims

A heat source unit constituting a refrigeration apparatus (1), the refrigeration apparatus (1) including at least one showcase (50), the at least one showcase (50) including a first utilization heat exchanger (54) connected to a refrigerant circuit (11), the heat source unit comprising:
a compression element (21, 22, 23), a first decompression mechanism (14), and a heat source heat exchanger (13) connected to the refrigerant circuit (11);

a detector (90) configured to detect a business status of a store including the at least one showcase (50); and

a control unit (C 1) configured to control operation of the refrigeration apparatus (1),

the control unit (C1, C3) executing a first operation that limits the operation of the refrigeration apparatus (1) if the store is detected to be outside business hours.
The heat source unit of claim 1, wherein
the first operation is an operation in which a duration of a thermostat off mode of the refrigeration apparatus (1) is longer than a duration of the thermostat off mode during business hours of the store.
The heat source unit of claim 1 or 2, wherein
the control unit (C1, C3) sets a first temperature at which a thermostat off mode of the refrigeration apparatus (1) ends in the first operation to be higher than the first temperature during business hours of the store.
The heat source unit of any one of claims 1 to 3, wherein
in the first operation, the control unit (C1, C3) sets a target evaporation temperature of a refrigerant in the first utilization heat exchanger (54) to be higher than the target evaporation temperature of the refrigerant in the first utilization heat exchanger (54) during business hours of the store.
The heat source unit of any one of claims 1 to 4, wherein
the first operation is an operation in which a rate of increase in an operation frequency of the compression element (21, 22, 23) is lower than a rate of increase in the operation frequency of the compression element (21, 22, 23) during business hours of the store (T).
The heat source unit of any one of claims 1 to 5, wherein
When it is detected that the store (T) has entered business hours, the control unit (C1, C3) is prevented from executing the first operation.
The heat source unit of any one of claims 1 to 6, wherein
the detector (90) detects that a first member (59) that restricts a change in air temperature in the at least one showcase (50) has been attached to the at least one showcase (50), and

if it is detected that the first member (59) has been attached to the at least one showcase (50), the control unit (C1, C3) determines that the store is detected to be outside business hours.
The heat source unit of any one of claims 1 to 7, wherein
the refrigeration apparatus (1) includes the multiple showcases (50), and

the control unit (C1, C3) executes the first operation for a target one of the multiple showcases (50).
A refrigeration apparatus comprising:
the heat source unit (10) of any one of claims 1 to 8; and

the at least one showcase (50).
The refrigeration apparatus of claim 9, wherein
the at least one showcase (50) includes a transparent panel (70) and a heater (75) configured to reduce fogging of the transparent panel (70), and

the control unit (C1, C3) limits operation of the heater (75) in the first operation.
The refrigeration apparatus of claim 9 or 10, wherein
the at least one showcase (50) includes a second decompression mechanism (53) connected to the refrigerant circuit (11), and

the control unit (C1, C3) controls the second decompression mechanism (53) to allow a degree of superheat of a suction refrigerant sucked from the first utilization heat exchanger (54) into the compression element (21, 22, 23) in the first operation to be higher than the degree of superheat before start of the first operation.
The refrigeration apparatus of any one of claims 9 to 11, further comprising:
an indoor unit (60) configured to condition air in an indoor space in the store (T), wherein

the indoor unit (60) includes a second utilization heat exchanger (64) connected to the refrigerant circuit (11),

the compression element (21, 22, 23) includes a first compressor (21) configured to compress a refrigerant flowing out of the first utilization heat exchanger (54), and a second compressor (22) configured to compress the refrigerant flowing out of the second utilization heat exchanger (64), and

if, in the first operation, adjustment of a temperature in the at least one showcase (50) has priority over air conditioning in the indoor space, the control unit (C1, C3) increases an operation frequency of the first compressor (21).