US20250369665A1

US20250369665A1 - Refrigeration cycle apparatus

Info

Publication number: US20250369665A1
Application number: US18/963,005
Authority: US
Inventors: Naoto Ishii
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2024-05-28
Filing date: 2024-11-27
Publication date: 2025-12-04
Also published as: JP2025179508A

Abstract

A refrigeration cycle apparatus having a housing in which at least a portion of a refrigerant circuit through which refrigerant circulates is located, the housing forming an outer shell and having a front side portion, the front side portion being removable, wherein the at least portion of the refrigerant circuit includes a condenser, a pressure container in which the refrigerant is reserved, a first pipe through which the refrigerant flows, the first pipe connecting the condenser and the pressure container, and a pressure relief device having a fusible plug, provided on the first pipe, and configured to release the refrigerant when a pressure in the first pipe reaches a predetermined pressure, and a portion of the first pipe, on which the pressure relief device is provided, is located beside the front side portion in the housing.

Description

TECHNICAL FIELD

The present disclosure relates to a refrigeration cycle apparatus having a refrigerant circuit, such as a heat pump chiller, and particularly relates to an attachment structure of a fusible plug in the refrigerant circuit.

BACKGROUND ART

In a refrigeration cycle apparatus such as a heat pump chiller, as means for protecting a refrigerant circuit from an excessive pressure increase, conventional techniques have been established, such as protection with a pressure switch, software protection using values detected by a pressure sensor, and protection by a controller instead of using the pressure switch and the pressure sensor.
However, for example, in the United States, devices having a pressure container in a refrigerant circuit, such as an air-conditioning device, a chiller device, and a water heating device, are required to be provided with a physical device designed to release refrigerant safely, such as a fusible plug or a safety valve, based on the safety standards, UL60335-2-40. The conventionally-used pressure switch, pressure sensor, and pressure control are not adequate enough to comply with UL60335-2-40. It is thus necessary to provide a pressure relief device such as a fusible plug (that is, a safety device). Patent Literature 1 discloses a safety device for a refrigerating machine. The safety device includes a fusible plug. The fusible plug is a device to detect a temperature and release refrigerant.

CITATION LIST

Patent Literature

- Patent Literature 1: Japanese Utility Model Laid-Open No. S57-198472

SUMMARY OF INVENTION

Technical Problem

In a refrigeration cycle apparatus, there is a case where the refrigerant circuit uses the fusible plug. In that case, since the fusible plug is a device to detect a temperature and release refrigerant, a worker needs to work with great care to prevent the fusible plug from improperly operating during the servicing such as maintenance and regular inspection, or during the device assembly. The refrigeration cycle apparatus (refrigerating machine) in Patent Literature 1 has a problem that the fusible plug located on the rearward side in a main-body casing makes it difficult for a worker to work on or check the fusible plug during the servicing and other process, resulting in a decrease in work efficiency.
The present disclosure has been made in view of the above problems, and it is an object of the present disclosure to provide a refrigeration cycle apparatus including a fusible plug to result in an improvement in work efficiency during its servicing and other process.

Solution to Problem

A refrigeration cycle apparatus according to an embodiment of the present disclosure is a refrigeration cycle apparatus having a housing in which at least a portion of a refrigerant circuit through which refrigerant circulates is located, the housing forming an outer shell and having a front side portion, the front side portion being removable, wherein the at least portion of the refrigerant circuit includes a condenser, a pressure container in which the refrigerant is reserved, a first pipe through which the refrigerant flows, the first pipe connecting the condenser and the pressure container, and a pressure relief device having a fusible plug, provided on the first pipe, and configured to release the refrigerant when a pressure in the first pipe reaches a predetermined pressure, and a portion of the first pipe, on which the pressure relief device is provided, is located beside the front side portion in the housing.

Advantageous Effects of Invention

According to the embodiment of the present disclosure, it is possible in the refrigeration cycle apparatus including the fusible plug to result in an improvement in work efficiency during its servicing and other process.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a circuit configuration diagram of a heat pump chiller system including a refrigeration cycle apparatus according to Embodiment 1.

FIG. 2 is an external perspective view of the refrigeration cycle apparatus according to Embodiment 1.

FIG. 3 is a schematic diagram illustrating a positional relationship between a fusible plug and a pressure container inside a housing of the refrigeration cycle apparatus according to Embodiment 1.

FIG. 4 is a plan view illustrating an internal configuration of the refrigeration cycle apparatus according to Embodiment 1.

FIG. 5 illustrates a configuration example of the fusible plug in the refrigeration cycle apparatus according to Embodiment 1.

FIG. 6 is a front view of a pressure relief device and a pipe on which the pressure relief device is provided, illustrating a first modification of the pressure relief device in FIG. 3 .

FIG. 7 is a cross-sectional view of the pressure relief device and the pipe taken along the A-A line in FIG. 6 .

FIG. 8 is a front view illustrating a second modification of the pressure relief device in FIG. 3 .

FIG. 9 is a circuit configuration diagram illustrating another configuration example of the heat pump chiller system in FIG. 1 .

DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of a refrigeration cycle apparatus according to the present disclosure when it is applied to a heat pump chiller (hereinafter, referred to as a “chiller unit 1”) will be described with reference to the drawings. The present disclosure is not limited to the embodiment described below, and can be variously modified without departing from the gist of the present disclosure. In addition, the present disclosure includes all combinations of configurations that can be combined among the configurations shown in the embodiment described below. In particular, the combination of constituent elements is not limited to only the combination in each embodiment, and the constituent elements described in one embodiment can be applied to another embodiment. The refrigeration cycle apparatus is illustrated in the drawings merely as an example of a device to which the refrigeration cycle apparatus of the present disclosure is applied. The refrigeration cycle apparatus illustrated in the drawings does not intend to limit the devices to which the present disclosure is applied. The refrigeration cycle apparatus may be an air-conditioning apparatus, a water heating device, a refrigerator, or a freezer. In the descriptions below, terms that represent directions (for example, “up,” “down,” “right,” “left,” “front,” and “rear”) are appropriately used for the sake of easy understanding. However, these terms are used merely for description purposes, and are not intended to limit the present disclosure. In the drawings below, the same reference signs denote the same or equivalent components, which are common throughout the entire specification. Note that the relative relationship of sizes of the constituent components, the shapes of the constituent components, and the like in the drawings may differ from those of actual ones.

Embodiment 1

FIG. 1 is a circuit configuration diagram of a heat pump chiller system 100 including a refrigeration cycle apparatus (the chiller unit 1) according to Embodiment 1. In FIG. 1 , the heat pump chiller system 100 guides cooled water or heated water from the chiller unit 1 to a load side to perform cooling or heating. The heat pump chiller system 100 includes a refrigerant circuit 20 using flammable refrigerant such as hydrocarbon. Note that it is allowable that the refrigerant circuit 20 uses other type of refrigerant than the flammable refrigerant. The heat pump chiller system 100 includes a water circuit 9 through which a heat medium such as water circulates.
In FIG. 1 , the refrigerant circuit 20 has a compressor 21 configured to compress and discharge refrigerant, a condenser 22 configured to allow the refrigerant discharged from the compressor 21 to exchange heat with water in the water circuit 9, an expansion valve 23 configured to reduce the pressure of refrigerant on the downstream side of the condenser 22, and an evaporator 24 configured to allow the refrigerant whose pressure has been reduced to evaporate. These elements are connected annularly by a pipe. The condenser 22 is, for example, a water heat exchanger such as a plate heat exchanger. The evaporator 24 is an air heat exchanger configured to allow refrigerant to exchange heat with air (outside air), and is for example a fin-and-tube heat exchanger. In the refrigerant circuit 20, a pressure container 25 and a pressure relief device 6 having a fusible plug 61 are provided.
The pressure container 25 is provided on a pipe connecting a refrigerant outlet on the condenser 22 and a refrigerant inlet on the evaporator 24 in the refrigerant circuit 20. In FIG. 1 , the pressure container 25 is provided on the pipe extending between the condenser 22 and the expansion valve 23. Note that the pressure container 25 may be provided on the pipe extending between the expansion valve 23 and the evaporator 24. The pressure container 25 is configured to temporarily reserve refrigerant in the refrigerant circuit 20.
There is the pressure relief device 6 on a liquid-refrigerant pipe portion in the refrigerant circuit 20, where liquid refrigerant flows. In FIG. 1 , the pressure relief device 6 is provided on a pipe 7 extending between the condenser 22 and the pressure container 25 in the refrigerant circuit 20. Hereinafter, the pipe 7 connecting the condenser 22 and the pressure container 25 may sometimes be referred to as a “first pipe.”
The pressure relief device 6 is set to operate when the pressure in the refrigerant circuit 20 reaches a predetermined pressure. The pressure relief device 6 is configured to allow the refrigerant to leak when an anomaly has occurred and then the refrigerant pressure in the refrigerant circuit 20 increases to the predetermined pressure. When the pressure in the refrigerant circuit 20 reaches the predetermined pressure, the refrigerant is released from the pressure relief device 6 where the refrigerant is most likely to leak in the refrigerant circuit 20. The pressure relief device 6 releases the refrigerant to release the pressure in the refrigerant circuit 20, thereby serving as a protection device (safety device) for a part of the circuit other than the pressure relief device 6.
The pressure relief device 6 has the fusible plug 61 and a branch pipe 62 that branches off from a main pipe (the pipe 7) of the refrigerant circuit 20. In general, a fusible plug includes a fuse element (fusible alloy) that seals a container filled with gas and melts at a certain temperature. When the temperature in the container increases excessively, the fuse element melts, through which the gas is released, thereby to prevent the container from being broken.
In this example, in order that the fusible plug 61 operates when the refrigerant pressure in the pipe 7 provided with the pressure relief device 6 reaches a specified pressure in the refrigerant circuit 20, a fuse element appropriate to the specified pressure is used. With this configuration, when the refrigerant pressure in the refrigerant circuit 20 increases to a predetermined pressure, that is, the refrigerant pressure in the pipe 7 reaches the specified pressure, then the refrigerant is released from the fusible plug 61. Since the refrigerant is released from the fusible plug 61 where the refrigerant is most likely to be released in the refrigerant circuit 20, it is possible to cause the refrigerant to leak at a fixed position in the refrigerant circuit 20.
The specified pressure described above is determined depending on the pressure resistance, for example, depending on the configuration of the refrigerant circuit 20, the type of refrigerant to be used, and the maximum pressure in the refrigerant circuit 20 during operation. The fusible plug 61 is provided in such a manner as to satisfy, for example, the US safety standards, UL60335-2-40 Edition 3 22.112DV.9.
FIG. 2 is an external perspective view of the refrigeration cycle apparatus according to Embodiment 1. FIG. 3 is a schematic diagram illustrating a positional relationship between the fusible plug 61 and the pressure container 25 inside a housing 10 (see FIG. 2 ) of the refrigeration cycle apparatus according to Embodiment 1. The solid arrow illustrated in FIG. 3 shows a refrigerant flow direction. FIG. 4 is a plan view illustrating an internal configuration of the refrigeration cycle apparatus according to Embodiment 1.
As illustrated in FIGS. 2 and 4 , the refrigeration cycle apparatus (the chiller unit 1) has the housing 10 forming the outer shell. On one of the sides of the housing 10, a maintenance side is provided. The maintenance side is a removable panel that can be removed to open a portion of the housing 10 for a worker to repair or check the parts inside the housing 10 during the servicing such as maintenance and regular inspection or during the device assembly. Hereinafter, a front side portion 13 of the housing 10 is defined as the maintenance side, and directional terms (for example, “up,” “down,” “right,” “left,” “front,” and “rear”) are supposed to represent directions when the chiller unit 1 is viewed from the front side on which the maintenance side is provided.
The housing 10 is formed in a hollow cuboid shape, and has a top side portion 11, a bottom side portion 12, a right side portion 15, a left side portion 16, a back side portion 14, and the front side portion 13 that is removable as the maintenance side.
The chiller unit 1 has a configuration in which the above refrigerant circuit 20 is accommodated in the housing 10. An air outlet is formed on the top side portion 11. A fan 30 is located at the air outlet. Air inlets are formed on the right side portion 15, the back side portion 14, and the left side portion 16 of the housing 10. As illustrated in FIG. 4 , the evaporator 24 is located on the inner side of the right side portion 15, the back side portion 14, and the left side portion 16.
Note that the refrigeration cycle apparatus of the present disclosure does not necessarily have all the elements of the refrigerant circuit 20. It suffices that the refrigeration cycle apparatus has at least some of the elements of the refrigerant circuit 20 (including the condenser 22, the pressure container 25, the pipe 7 connecting the condenser 22 and the pressure container 25, and the pressure relief device 6 provided on the pipe 7). The refrigeration cycle apparatus may be, for example, an outdoor unit of an air-conditioning device.
The US safety standards, UL60335-2-40, impose several restrictions on the location of the pressure relief device 6. In the UL60335-2-40, for example, Edition 3 22.112DV.11 stipulates that “All the pressure relief means shall be connected adjacent to, or connected directly to, a pressure container or a portion of the system to be protected. The pressure relief device shall be connected at a position higher than the liquid refrigerant level, and be installed in an easily accessible manner for inspection and repair, and in such a manner as to protect from conditions that may possibly cause improper operation.”
As illustrated in FIG. 3 , the fusible plug 61 is located higher than the pressure container 25 in the housing 10. As also illustrated in FIG. 4 , the pressure relief device 6 is provided on the pipe 7 extending between the condenser 22 and the pressure container 25 in the refrigerant circuit 20. In FIGS. 3 and 4 , in the manner as described above, the pressure relief device 6 satisfies the stipulations described above, and thus complies with the UL60335-2-40.
In FIGS. 3 and 4 , the condenser 22 and the pressure container 25 are installed on the bottom side portion 12 of the housing 10. The fusible plug 61 is located on the pipe 7 extending between the condenser 22 and the pressure container 25 near the condenser 22 whose height is greater of the condenser 22 and the pressure container 25. In FIGS. 3 and 4 , the pipe 7 extending between the condenser 22 and the pressure container 25 includes a first pipe portion 71 extending in a horizontal direction from the refrigerant outlet on the condenser 22, a second pipe portion 72 extending in the horizontal direction from the refrigerant inlet on the pressure container 25 and located at a position lower than the first pipe portion 71 (that is, near the bottom side portion 12), and a connection pipe portion 73 connecting the first pipe portion 71 and the second pipe portion 72. The pipe 7 is formed in substantially a Z-shape.
As illustrated in FIG. 4 , a portion of the pipe 7 extending between the condenser 22 and the pressure container 25 is located beside the front side portion 13 of the housing 10, and the fusible plug 61 is located in close proximity to the front side portion 13. In FIG. 4 , the condenser 22 and the compressor 21 are located on the forward side in the housing 10, while the pressure container 25 is located in the rear of the compressor 21. Due to this arrangement, in FIGS. 3 and 4 , in the pipe 7 extending between the condenser 22 and the pressure container 25, the first pipe portion 71 near the condenser 22 is located on the forward side relative to the second pipe portion 72 near the pressure container 25, such that the first pipe portion 71 runs along the front side portion 13 of the housing 10. The fusible plug 61 is attached to the first pipe portion 71 through the branch pipe 62.
Specifically, in the pressure relief device 6 in FIGS. 3 and 4 , the branch pipe 62 straightly extending upward is provided on the upper side of the first pipe portion 71 in the pipe 7, and the fusible plug 61 is provided at an upper end of the branch pipe 62. The branch pipe 62 provided in this manner allows the fusible plug 61 to be located at a relatively high position in the housing 10.
Note that the pressure relief device 6 may have a configuration in which the fusible plug 61 is directly attached to the pipe 7 extending between the condenser 22 and the pressure container 25, however, it is structurally desirable to have a configuration in which the fusible plug 61 is attached to the pipe 7 through the branch pipe 62, such that a direction in which or the position to which refrigerant is released is easily adjusted.
FIG. 5 illustrates a configuration example of the fusible plug 61 in the refrigeration cycle apparatus according to Embodiment 1. As illustrated in FIG. 5 , the fusible plug 61 includes a plug attachment portion 612 to be attached to the branch pipe 62 (or to the pipe 7 when the fusible plug 61 is directly installed on the pipe 7), and an outlet portion 611 from which refrigerant is released. In the fusible plug 61, a hole 610 is formed connecting the refrigerant inlet on the plug attachment portion 612 and the refrigerant outlet on the outlet portion 611. The hole 610 is normally closed by the fuse element (not illustrated).
With reference to FIGS. 1, 2, and 5 , operation of the heat pump chiller system 100 is now described. In the refrigerant circuit 20 of the heat pump chiller system 100, gas refrigerant heated to a high temperature and compressed to a high pressure by the compressor 21 enters a refrigerant pipe (not illustrated) in the condenser 22, and exchanges heat with water flowing in the water circuit 9 and passing through a water pipe (not illustrated) in the condenser 22. The water is heated in the condenser 22, while the refrigerant having transferred heat to the water flows out from the condenser 22, reaches the expansion valve 23, is reduced in pressure by the expansion valve 23, and then enters the evaporator 24. The refrigerant having entered the evaporator 24 receives heat from outside air delivered by the fan 30 (see FIG. 2 ), is then evaporated and gasified in the evaporator 24, and thereafter returns to the compressor 21. A controller (not illustrated) controls an actuator of the refrigerant circuit 20 in response to the water temperature in the water circuit 9.
When the heat pump chiller system 100 is affected by some external factors, for example, when the ambient temperature excessively increases, the refrigerant pressure in the refrigerant circuit 20 increases, which may possibly cause cracks on the pipe and other constituent elements of the refrigerant circuit 20. If the cracks appear, flammable refrigerant in the refrigerant circuit 20 leaks to the outside through the cracks. In the present embodiment, when the refrigerant pressure in the refrigerant circuit 20 increases, and thus there is a possibility that cracks may appear on the pipe and other constituent elements of the refrigerant circuit 20, that is, when the pressure in the refrigerant circuit 20 increases and the refrigerant pressure in the pipe 7 reaches a specified pressure, then the pressure relief device 6 operates, so that the refrigerant is released from the pressure relief device 6 where the refrigerant is most likely to be released in the refrigerant circuit 20. More specifically, as the pressure in the refrigerant circuit 20 increases anomalously, the temperature accordingly increases. Consequently, the fuse element (not illustrated) of the fusible plug 61 illustrated in FIG. 5 melts and thus the hole 610 is opened, from which refrigerant is released to the outside, so that the internal pressure of the refrigerant circuit 20 is released to the outside.
In the configuration example in FIG. 5 , the fusible plug 61 has an outer circumferential portion 613 provided with a male thread. Specifically, thread cutting has been done on the outer circumferential portion of the outlet portion 611. In this manner, the fusible plug 61 is threaded (male-threaded) on the outer circumferential portion 613, which allows, for example, a refrigerant recovery device (not illustrated) configured to recover refrigerant to be directly connected to the fusible plug 61.
Therefore, it is possible to connect the refrigerant recovery device (not illustrated) to the fusible plug 61 during, for example, assembly of the device to be filled with refrigerant, or inspection during which the refrigeration cycle apparatus may operate in different mode from the normal mode. Accordingly, even if the fusible plug 61 operates improperly, causing the refrigerant to be discharged, it is still possible to avoid the refrigerant from scattering to the peripheral devices around the fusible plug 61. This allows the peripheral devices to be protected from the refrigerant, and results in an improvement in the work efficiency. As illustrated in FIG. 4 , in the housing 10, the fusible plug 61 is located beside the maintenance side (the front side portion 13), so that even when the refrigerant recovery device or other device is temporarily connected to the fusible plug 61 during the device assembly or inspection, a work space can still be easily ensured.
There is a case where in the housing 10, flammable elements (for example, a structure made of resin) are provided in proximity to the pipe 7 on which the pressure relief device 6 is provided. In that case, it is desirable that the position to which or the direction in which refrigerant is released from the fusible plug 61 can be adjusted in such a manner as to prevent these flammable elements from contacting the refrigerant. Examples of the flammable elements include a covered wire and a control device. In FIG. 3 , the pipe 7 and the fusible plug 61 are connected through the branch pipe 62 extending upward, so that it is possible to adjust the position of the fusible plug 61 (particularly, the refrigerant outlet) in its height direction.
Note that the shape, the orientation, and the length of the branch pipe 62 are not limited to the shape, the orientation, and the length described above. It is also allowable to determine the shape, the orientation, and the length of the branch pipe 62 depending on the positional relationship with the structures in the chiller unit 1 in which the pressure relief device 6 is installed. Two modifications of the pressure relief device 6 are described below.

(First Modification)

FIG. 6 is a front view of a pressure relief device 106 and the pipe 7 on which the pressure relief device 106 is provided, illustrating a first modification of the pressure relief device 6 in FIG. 3 . FIG. 7 is a cross-sectional view of the pressure relief device 106 and the pipe 7 taken along the A-A line in FIG. 6 . As illustrated in FIG. 6 , in the first modification, a branch pipe 162 is provided to be bent in such a manner that a tip of the fusible plug 61, from which refrigerant is discharged, is directed not toward the flammable elements.
As illustrated in FIGS. 6 and 7 , the branch pipe 162 is formed in an L-shape. The branch pipe 162 includes a first straight pipe portion 162 a extending parallel to the pipe 7, a second straight pipe portion 162 b connected to the pipe 7 perpendicularly to the pipe 7, and a curved portion 162 c connecting the first straight pipe portion 162 a and the second straight pipe portion 162 b. At a tip end portion of the branch pipe 162 (that is, a tip end portion of the first straight pipe portion 162 a), an attachment portion 162 d is provided to which the fusible plug 61 is attached. The plug attachment portion 612 (see FIG. 5 ) of the fusible plug 61 is positioned on the inner circumferential side of the attachment portion 162 d.
In FIGS. 6 and 7 , the first straight pipe portion 162 a extends parallel to the pipe 7 as described above. That is, the branch pipe 162 is bent toward the same direction as the refrigerant flow direction in the pipe 7 which is the main pipe of the refrigerant circuit 20. With this configuration, it is possible for the fusible plug 61 to detect the temperature of refrigerant accurately. That is, even when the length of the branch pipe 162 needs to be increased by the amount of bending the branch pipe 162, it is still possible to locate the fusible plug 61 close to the pipe 7. As a result, the fuse element is affected sufficiently by the temperature increase due to the pressure increase, and then melts properly, so that the pressure relief device 106 functions normally.
In a case where the branch pipe 162 of the pressure relief device 106 includes the curved portion 162 c, it is possible to adjust the orientation of the fusible plug 61 in such a manner that its tip from which refrigerant is discharged is directed not toward the flammable elements as described above. While these effects are still achieved even in a case where refrigerant is non-flammable, particularly in a case where refrigerant is flammable, these effects result in an improvement in safety, which is effective.

(Second Modification)

FIG. 8 is a front view of a pressure relief device 206, illustrating a second modification of the pressure relief device 6 in FIG. 3 . As illustrated in FIG. 8 , in the second modification, a capillary tube (with a length of, for example, approximately several tens of centimeters) is used as a connection pipe (that is, a branch pipe 262) connecting the fusible plug 61 and the pipe 7 on which the pressure relief device 206 is provided. The fusible plug 61 is connected to the pipe 7 through the capillary tube.
In FIG. 8 , the branch pipe 262 includes an annular portion 262 c formed into an annular shape, a branch pipe base portion 262 b extending straightly from one end of the annular portion 262 c, and a branch pipe tip end portion 262 a extending straightly from the other end of the annular portion 262 c. The branch pipe base portion 262 b is connected to the pipe 7. The fusible plug 61 is attached to the branch pipe tip end portion 262 a.
In FIG. 8 , at locations of the annular portion 262 c that are opposite to each other (on the upper side and the lower side of the annular portion 262 c illustrated in FIG. 8 ), one end and the other end thereof are provided, and opened toward the same direction (on the right side in FIG. 8 ). The branch pipe base portion 262 b and the branch pipe tip end portion 262 a both extend in the same direction along their respective tangents to the annular portion 262 c.
Note that the positional relationship between one end and the other end of the annular portion 262 c, and the shape and the extending direction of the branch pipe base portion 262 b and the branch pipe tip end portion 262 a are not limited to those described above, and may be appropriately set such that refrigerant is released in a desired direction or to a desired position. As illustrated in FIG. 8 , using the capillary tube to serve as the branch pipe 262 of the pressure relief device 206 makes it possible to easily set the direction in which or the position to which refrigerant is released.
While FIG. 3 illustrates the case where the pressure relief device 6 (particularly, the branch pipe 62) is connected to the upper side of the pipe 7, it is allowable that the pressure relief device 6, 106, or 206 (the branch pipe 62, 162, or 262) is connected to any location on the pipe 7.
FIG. 9 is a circuit configuration diagram illustrating another configuration example of the heat pump chiller system 100 in FIG. 1 . The chiller unit 1 illustrated in FIG. 9 includes a high-pressure switch 40 as an additional safety device separate from the pressure relief device 206. The high-pressure switch 40 is configured to operate when the high-pressure side pressure in the refrigerant circuit 20 reaches an upper limit. The high-pressure switch 40 may be either an electrical switch or a mechanical switch using a diaphragm. The high-pressure switch 40 is provided on a pipe 8 extending between the compressor 21 and the condenser 22 in the refrigerant circuit 20. Hereinafter, the pipe 8 connecting the compressor 21 and the condenser 22 may sometimes be referred to as a “second pipe.”
In the heat pump chiller system 100 illustrated in FIG. 9 , the high-pressure switch 40 and the pressure relief device 206 are provided in the refrigerant circuit 20. As illustrated in FIGS. 8 and 9 , the capillary tube is used to serve as the branch pipe 262 of the pressure relief device 206, which allows a pipe length from the pipe 7 to the fusible plug 61 to be increased relative to a distance between the pipe 7 and the fusible plug 61. Accordingly, it is possible to decrease the temperature of refrigerant by the time the refrigerant reaches the fusible plug 61.
Therefore, when the refrigerant circuit 20 is, for example, under the condition of adequate pressure despite high temperature, and thus the pressure relief device 206 (the fusible plug 61) does not need to be operated, then the high-pressure switch 40 that needs to be operated prior to the fusible plug 61 can be operated with a priority over the fusible plug 61. This can prevent the fusible plug 61 from being improperly operated.
As described above, the refrigeration cycle apparatus according to Embodiment 1 (for example, the chiller unit 1) is a refrigeration cycle apparatus having the housing 10 in which at least a portion of the refrigerant circuit 20 through which refrigerant circulates is located. The housing 10 forms the outer shell and has the front side portion 13. The front side portion 13 is removable. The at least portion of the refrigerant circuit 20 includes the condenser 22, the pressure container 25 in which refrigerant is reserved, the first pipe (the pipe 7) through which refrigerant flows, and connecting the condenser 22 and the pressure container 25, and the pressure relief device 6. The pressure relief device 6 has the fusible plug 61, is provided on the first pipe (the pipe 7), and is configured to release refrigerant when the pressure in the first pipe reaches a predetermined pressure. A portion of the first pipe (the pipe 7), on which the pressure relief device 6 is provided (the first pipe portion 71 in FIGS. 3 and 4 ), is located beside the front side portion 13 in the housing 10. More specifically, when the front side portion 13 is removed, the fusible plug 61 is located at a position where the fusible plug 61 is exposed to the outside, that is, at a position where the fusible plug 61 can be viewed from the front.
This allows the fusible plug 61 to be located beside the front side portion 13 used as the maintenance side in the housing 10, and thus helps a worker to check and work on the fusible plug 61 easily during the servicing or the device assembly. This can improve the work efficiency.
The fusible plug 61 has the outer circumferential portion 613 provided with a male thread. The male thread is provided on the outer circumferential portion 613 of the fusible plug 61 as described above, so that it is possible to directly connect the refrigerant recovery device configured to recover refrigerant (for example, a container) or other device to the fusible plug 61, and reduce the influence of improperly discharged refrigerant on the peripheral devices during the work.
The pressure relief device 6 has the branch pipe 62 connecting the fusible plug 61 and a portion of the first pipe (the first pipe portion 71). With this configuration, it is possible to adjust the position to which or the direction in which refrigerant is released from the fusible plug 61.
The branch pipe 162 includes the curved portion 162 c. The curved portion 162 c of the branch pipe 162 is formed such that the tip end portion (the first straight pipe portion 162 a) extends in the direction in which the portion of the first pipe (the first pipe portion 71) extends.
With this configuration, even when the fusible plug 61 is connected to the portion of the first pipe (the first pipe portion 71) through the branch pipe 162 including the curved portion 162 c, it is still possible to locate the fusible plug 61 near the first pipe (the pipe 7). It is thus possible for the fusible plug 61 to detect the temperature of refrigerant accurately and operate.
The branch pipe 262 is a capillary tube. With this configuration, it is possible to easily adjust the position to which or the direction in which refrigerant is released from the fusible plug 61. At least a portion of the refrigerant circuit 20 includes the compressor 21 configured to compress refrigerant, the second pipe (the pipe 8) connecting the compressor 21 and the condenser 22, and the high-pressure switch 40 provided on the second pipe.
As describe above, in the configuration in which the refrigerant circuit 20 is provided with both the pressure relief device 6 and the high-pressure switch 40, a capillary tube, which can easily ensure a sufficient pipe length, is used to serve as the branch pipe 262. This can make the fusible plug 61 slightly less sensitive compared to the high-pressure switch 40. Therefore, when the refrigerant circuit 20 is, for example, under the condition of adequate pressure despite high temperature, and thus the pressure relief device 6 does not need to be operated, then the high-pressure switch 40 that needs to be operated with a priority over the pressure relief device 6 can be operated prior to the pressure relief device 6. That is, it is possible to reduce improper operation of the fusible plug 61.
Various aspects of the present disclosure are appended below.

APPENDIX 1

A refrigeration cycle apparatus having a housing in which at least a portion of a refrigerant circuit through which refrigerant circulates is located, the housing forming an outer shell and having a front side portion, the front side portion being removable, wherein

- the at least portion of the refrigerant circuit includes
- a condenser,
- a pressure container in which the refrigerant is reserved,
- a first pipe through which the refrigerant flows, the first pipe connecting the condenser and the pressure container, and
- a pressure relief device having a fusible plug, provided on the first pipe, and configured to release the refrigerant when a pressure in the first pipe reaches a predetermined pressure, and
- a portion of the first pipe, on which the pressure relief device is provided, is located beside the front side portion in the housing.

APPENDIX 2

The refrigeration cycle apparatus of appendix 1, wherein the fusible plug has an outer circumferential portion provided with a male thread.

APPENDIX 3

The refrigeration cycle apparatus of appendix 1 or 2, wherein the pressure relief device has a branch pipe connecting the fusible plug and the portion of the first pipe.

APPENDIX 4

The refrigeration cycle apparatus of appendix 3, wherein the branch pipe includes a curved portion.

APPENDIX 5

The refrigeration cycle apparatus of appendix 4, wherein the curved portion of the branch pipe is formed such that a tip end portion of the branch pipe extends in a direction in which the portion of the first pipe extends.

APPENDIX 6

The refrigeration cycle apparatus of any one of appendixes 3 to 5, wherein the branch pipe is a capillary tube.

APPENDIX 7

The refrigeration cycle apparatus of any one of appendixes 1 to 6, wherein the at least portion of the refrigerant circuit includes

- a compressor configured to compress the refrigerant,
- a second pipe connecting the compressor and the condenser, and
- a high-pressure switch provided on the second pipe.

REFERENCE SIGNS LIST

1: chiller unit, 6: pressure relief device, 7: pipe, 8: pipe, 9: water circuit, 10: housing, 11: top side portion, 12: bottom side portion, 13: front side portion, 14: back side portion, 15: right side portion, 16: left side portion, 20: refrigerant circuit, 21: compressor, 22: condenser, 23: expansion valve, 24: evaporator, 25: pressure container, 30: fan, 40: high-pressure switch, 61: fusible plug, 62: branch pipe, 71: first pipe portion, 72: second pipe portion, 73: connection pipe portion, 100: heat pump chiller system, 106: pressure relief device, 162: branch pipe, 162 a: first straight pipe portion, 162 b: second straight pipe portion, 162 c: curved portion, 162 d: attachment portion, 206: pressure relief device, 262: branch pipe, 262 a: branch pipe tip end portion, 262 b: branch pipe base portion, 262 c: annular portion, 610: hole, 611: outlet portion, 612: plug attachment portion, 613: outer circumferential portion

Claims

1. A refrigeration cycle apparatus having a housing in which at least a portion of a refrigerant circuit through which refrigerant circulates is located, the housing forming an outer shell and having a front side portion, the front side portion being removable, wherein

the at least portion of the refrigerant circuit includes

a condenser,

a pressure container in which the refrigerant is reserved,

a first pipe through which the refrigerant flows, the first pipe connecting the condenser and the pressure container, and

a pressure relief device having a fusible plug, provided on the first pipe, and configured to release the refrigerant when a pressure in the first pipe reaches a predetermined pressure, and

a portion of the first pipe, on which the pressure relief device is provided, is located beside the front side portion in the housing.

2. The refrigeration cycle apparatus of claim 1, wherein the fusible plug has an outer circumferential portion provided with a male thread.

3. The refrigeration cycle apparatus of claim 1, wherein the pressure relief device has a branch pipe connecting the fusible plug and the portion of the first pipe.

4. The refrigeration cycle apparatus of claim 3, wherein the branch pipe includes a curved portion.

5. The refrigeration cycle apparatus of claim 4, wherein the curved portion of the branch pipe is formed such that a tip end portion of the branch pipe extends in a direction in which the portion of the first pipe extends.

6. The refrigeration cycle apparatus of claim 3, wherein the branch pipe is a capillary tube.

7. The refrigeration cycle apparatus of claim 6, wherein the at least portion of the refrigerant circuit includes

a compressor configured to compress the refrigerant,

a second pipe connecting the compressor and the condenser, and

a high-pressure switch provided on the second pipe.

8. The refrigeration cycle apparatus of claim 2, wherein the pressure relief device has a branch pipe connecting the fusible plug and the portion of the first pipe.

9. The refrigeration cycle apparatus of claim 8, wherein the branch pipe includes a curved portion.

10. The refrigeration cycle apparatus of claim 9, wherein the curved portion of the branch pipe is formed such that a tip end portion of the branch pipe extends in a direction in which the portion of the first pipe extends.

11. The refrigeration cycle apparatus of claim 8, wherein the branch pipe is a capillary tube.

12. The refrigeration cycle apparatus of claim 11, wherein the at least portion of the refrigerant circuit includes

a compressor configured to compress the refrigerant,

a second pipe connecting the compressor and the condenser, and

a high-pressure switch provided on the second pipe.