GB2557837A

GB2557837A - Refrigerant quantity management device and refrigerant quantity management system

Info

Publication number: GB2557837A
Application number: GB1806219.0A
Authority: GB
Inventors: Maeda Migifumi; Obana Hiroaki; Sata Hiroshi; Morikawa Satoshi; Teshima Takahito
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-11-30
Filing date: 2015-11-30
Publication date: 2018-06-27
Anticipated expiration: 2035-11-30
Also published as: GB201806219D0; GB2557837C; JP6490237B2; GB2557837B; WO2017094059A1; JPWO2017094059A1

Abstract

Disclosed is a refrigerant quantity management device that manages the quantity of a refrigerant applied to a refrigerant circuit formed by connecting to each other using piping: a heat source-side unit having a compressor, a heat source-side heat exchanger, and a supercooler; and at least one load-side unit having a load-side expansion valve and a load-side heat exchanger. The refrigerant quantity management device has: a temperature efficiency calculation unit, which regularly obtains temperature efficiency, and stores the temperature efficiency in a storage unit; and an output control unit having a function of displaying, on a display unit, information indicating the temperature efficiency during a set period stored in the storage unit.

Description

(71) Applicant(s):

Mitsubishi Electric Corporation (Incorporated in Japan)

7-3 Marunouchi 2-chome, Chiyodaku,

Tokyo 100-8310, Japan (72) Inventor(s):

Migifumi Maeda Hiroaki Obana Hiroshi Sata Satoshi Morikawa Takahito Teshima (74) Agent and/or Address for Service:

Mewburn Ellis LLP

City Tower, 40 Basinghall Street, LONDON, Greater London, EC2V 5DE, United Kingdom (51) INT CL:

F25B 49/02 (2006.01) F25B 45/00 (2006.01) (56) Documents Cited:

WO 2015/004747 A1 WO 2013/183414 A1

WO 2008/035418 A1

JP 2008-196829 A

JP 4975052 B2

JP 2012132639 A

JP 55163573 A

Microfilm of the specification and drawings annexed to the request of Japanese Utility Model Application No. 025498/1984 (Laid open No. 137322/1985) (Yokogawa Hokushin Electric Corp.) 11 September 1985

JP 07104836 A JP 10307622 A JP 2004021949 A JP 2006275303 A

Microfilm of the specification and drawings annexed to the request of Japanese Utility Model Application No. 114324/1990 (Laid open No. 070975/1992) (Mitsubishi Industries, Ltd.) 23 June 1992 (58) Field of Search:

INT CL F25B

Other: Jitsuyo Shinan Koho 1922-1996; Jitsuyo Shinan Toroku Koho 1996-2016; Kokai Jitsuyo Shinan Koho 1971-2016; Toroku Jitsuyo Shinan Koho 1994-2016.

(54) Title of the Invention: Refrigerant quantity management device and refrigerant quantity management system Abstract Title: Refrigerant quantity management device and refrigerant quantity management system (57) Disclosed is a refrigerant quantity management device that manages the quantity of a refrigerant applied to a refrigerant circuit formed by connecting to each other using piping: a heat source-side unit having a compressor, a heat source-side heat exchanger, and a supercooler; and at least one load-side unit having a load-side expansion valve and a load-side heat exchanger. The refrigerant quantity management device has: a temperature efficiency calculation unit, which regularly obtains temperature efficiency, and stores the temperature efficiency in a storage unit; and an output control unit having a function of displaying, on a display unit, information indicating the temperature efficiency during a set period stored in the storage unit.

SO

Data collecting unit

Storage unit

Operation state determining unit

Temperature efficiency calculation unit

Refrigerant quantity determining unit

Output control unit

Display unit

Communication unit

100 Refrigerant quantity management device ο

LL

230A 230B 230C 230D '’Φ

FIG. 2

3/14

FIG. 3

100

4/14

FIG. 4

LOW-SIDE PRESSURE

FIG. 5

THERMAL EFFICIENCY T

FIG. 6

τΐCD

FIG. 7

o

LL

PRE-ALARM (REFRIGERANT INSUFFICIENCY DETERMINATION) GRAPH DISPLAY (EXAMPLE)

8/14

FIG. 9

sr σ5

FIG. 10 <

10/14

FIG. 11

1OOA

73A

74B

70A

11/14

FIG. 12

100C

COLLECTION/CALCULATION DEVICE

DATA

COLLECTION UNIT

72C

73D74

OPERATION STATE DETERMINATION UNIT

THERMAL EFFICIENCY CALCULATION UNIT

REFRIGERANT AMOUNT DETERMINATION UNIT

OUTPUT CONTROL UNIT

100D

REFRIGERANT AMOUNT MANAGEMENT DEVICE

STORAGE UNIT

DISPLAY UNIT

COMMUNICATION UNIT

12/14

FIG. 13

73E

100E

72E

13/14

FIG. 14

73F

100F

14/14

FIG. 15

Ε

AMOUNT OF REFRIGERANT

DESCRIPTION

Title of Invention

REFRIGERANT AMOUNT MANAGEMENT DEVICE AND REFRIGERANT AMOUNT

MANAGEMENT SYSTEM

Technical Field [0001]

The present invention relates to a refrigerant amount management device and a refrigerant amount management system for managing the amount of refrigerant in a refrigeration device.

Background Art [0002]

With a refrigeration device, a too much or too little amount of refrigerant leads to failures such as reduced performance of the refrigeration device and occurrence of damages to structural appliances. To prevent such failures, a conventional refrigeration device has a function of determining an excess or deficiency in the amount of refrigerant that is charged, and of displaying a result of the determination (for example, see Patent Literature 1).

[0003]

A refrigeration device of Patent Literature 1 calculates a temperature difference between an inlet refrigerant temperature and an outlet refrigerant temperature of a subcooler as the degree of subcooling, and determines that there is a leakage of refrigerant when the calculated degree of subcooling is reduced to below a set value. Citation List

Patent Literature [0004]

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 9-105567

Summary of Invention

Technical Problem [0005]

However, the refrigeration device of Patent Literature 1 determines whether there is an insufficiency of refrigerant by associating, with the amount of refrigerant, the degree of subcooling that is greatly changed depending on an operation condition, and erroneous determination is likely to occur. Furthermore, the refrigeration device of Patent Literature 1 displays only the result of determination of the amount of refrigerant, and a person such as a service person cannot check a shift in the amount of refrigerant. Accordingly, an excess or deficiency in the amount of refrigerant may be caused due to necessary refrigerant not being charged when the amount of refrigerant is erroneously determined to be appropriate, or unnecessary refrigerant being charged when an insufficiency of refrigerant is erroneously determined.

[0006]

The present invention has been made to solve the problems as described above, and has its object to provide a refrigerant amount management device and a refrigerant amount management system for displaying information indicating a shift in the amount of refrigerant.

Solution to Problem [0007]

A refrigerant amount management device of one embodiment of the present invention is a refrigerant amount management device for managing an amount of refrigerant that is charged in a refrigerant circuit that is formed by connecting, by pipes, a heat source side unit including a compressor, a heat source side heat exchanger provided on a downstream of the compressor, and a subcooler provided on a downstream of the heat source side heat exchanger, and at least one load side unit including a load side expansion valve provided on a downstream of the subcooler, and a load side heat exchanger provided on a downstream of the load side expansion valve, the refrigerant amount management device including a storage unit for storing information about the amount of the refrigerant, a thermal efficiency calculation unit for periodically determining thermal efficiency by dividing a degree of subcooling of the refrigerant at an outlet of the subcooler by a maximum temperature difference that is a difference between a condensing temperature of the refrigerant and an outside temperature, and for causing the determined thermal efficiency to be stored in the storage unit, a display unit for displaying the information about the amount of the refrigerant, and an output control unit having a function of causing the display unit to display information, stored in the storage unit, indicating the thermal efficiency in a set period of time.

Advantageous Effects of Invention [0008]

According to one embodiment of the present invention, the output control unit causes the display unit to display information indicating the thermal efficiency, in a set period of time, periodically determined by the thermal efficiency calculation unit, and thus, information indicating a shift in the amount of refrigerant may be displayed.

Brief Description of Drawings [0009] [Fig. 1] Fig. 1 is a block diagram illustrating an overall configuration of a refrigerant amount management system according to Embodiment 1 of the present invention.

[Fig. 2] Fig. 2 is a schematic diagram illustrating an example of a configuration of a refrigeration device provided in the refrigerant amount management system in Fig. 1.

[Fig. 3] Fig. 3 is a block diagram illustrating an example of a configuration of a refrigerant amount management device provided in the refrigerant amount management system in Fig. 1.

[Fig. 4] Fig. 4 is a graph showing a relationship between fluctuations in a lowside pressure at a refrigerant circuit of the refrigeration device in Fig. 2 and a target low-side pressure.

[Fig. 5] Fig. 5 is an explanatory diagram showing a relationship between the amount of refrigerant in the refrigeration device shown in Fig. 2 and thermal efficiency.

[Fig. 6] Fig. 6 is a graph illustrating an example of a relationship between thermal efficiency and a refrigerant amount determination threshold in a set period of time, in a case where the amount of refrigerant is determined by a refrigerant amount determination unit in Fig. 3 to be appropriate.

[Fig. 7] Fig. 7 is a schematic diagram illustrating an example of information indicating an insufficiency in the amount of refrigerant, which is displayed in a case where an insufficiency of refrigerant is determined by the refrigerant amount determination unit in Fig. 3.

[Fig. 8] Fig. 8 is a graph illustrating an example of a relationship between thermal efficiency and a refrigerant amount determination threshold in a set period of time, in a case where an insufficiency of refrigerant is determined by the refrigerant amount determination unit in Fig. 3.

[Fig. 9] Fig. 9 is a flowchart describing an operation of a refrigerant amount management device 100 in Fig. 1.

[Fig. 10] Fig. 10 is a schematic diagram illustrating an example of a configuration of a refrigeration device according to Modification 1 of Embodiment 1 of the present invention.

[Fig. 11] Fig. 11 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Modification 2 of Embodiment 1 of the present invention.

[Fig. 12] Fig. 12 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Modification 3 of Embodiment 1 of the present invention.

[Fig. 13] Fig. 13 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Embodiment 2 of the present invention.

[Fig. 14] Fig. 14 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Embodiment 3 of the present invention.

[Fig. 15] Fig. 15 is an explanatory diagram showing a relationship between a change in a most recent period and a change over time, with respect to a refrigerant amount determination process by the refrigerant amount management device in Fig. 14.

Description of Embodiments [0010]

Embodiment 1.

Fig. 1 is a block diagram illustrating an overall configuration of a refrigerant amount management system according to Embodiment 1. As shown in Fig. 1, a refrigerant amount management system 300 includes a refrigerant amount management device 100, a plurality of refrigeration devices 200Aand 200B, and a plurality of remote controls 230A-230D.

[0011]

The refrigeration device 200A includes a heat source side unit 210A, a load side unit 220A, and a load side unit 220B. The refrigeration device 200B includes a heat source side unit 210B, a load side unit 220C, and a load side unit 220D.

[0012]

The refrigeration device 200A and the refrigeration device 200B have the same configuration, and in the following, the refrigeration devices 200A and 200B may be referred to collectively or singularly as refrigeration device 200. In the same manner, the heat source side units 210Aand 210B may be referred to collectively or singularly as heat source side unit 210. Furthermore, the load side units 220A220D may be referred to collectively or singularly as load side unit 220. Moreover, the remote controls 230A-230D may be referred to collectively or singularly as remote control 230.

[0013]

As shown in Fig. 1, a refrigerant circuit is formed by the refrigeration device 200A by connecting the heat source side unit 210A configured by a condensing unit, for example, the load side unit 220A, and the load side unit 220B by a refrigerant pipe. In the same manner, a refrigerant circuit is formed by the refrigeration device 200B by connecting the heat source side unit 210B configured by a condensing unit, for example, the load side unit 220C, and the load side unit 220D by a refrigerant pipe. The refrigeration device 200 performs cooling inside a room, such as a room, a warehouse, a showcase, or a refrigerator, by performing a vapor compression refrigeration cycle operation. That is, the refrigeration device 200 refrigerates or freezes a target object in a room, for example.

[0014]

The remote control 230 receives an input operation regarding air-conditioning control. Furthermore, the remote control 230 controls operation of the load side unit 220 by transmitting a signal related to an instruction regarding a set temperature to the load side unit 220 according to an input operation of a user, for example. The remote control 230A controls operation of the load side unit 220A, for example. The remote control 230B controls operation of the load side unit 220B, for example. The remote control 230C controls operation of the load side unit 220C, for example. The remote control 230D controls operation of the load side unit 220D, for example.

[0015]

Furthermore, the remote control 230 includes a display device (not shown) configured by a liquid crystal panel, and has a function of causing the display device to display information indicating the state of the refrigeration device 200, or the temperature inside a room which is a cooling target, for example.

[0016]

Fig. 1 illustrates an example of a case where the refrigerant amount management device 100 manages two refrigeration devices 200, but such a case is not restrictive, and the number of refrigeration devices 200 to be managed by the refrigerant amount management device 100 may be one, or three or more. Furthermore, Fig. 1 illustrates an example of a case where the refrigeration device 200 includes one heat source side unit 210, and two load side units 220, but such a case is not restrictive, and the refrigeration device 200 may include a plurality of heat source side units 210, and one or three or more load side units 220. In the case where there is a plurality of heat source side units 210, the capacity may be the same or different among the plurality of heat source side units 210. Furthermore, in the case where there is a plurality of load side units 220, the capacity may be the same or different among the plurality of load side units 220. Additionally, in the following, a description is given on the refrigeration device 200 according to which refrigerant exchanges heat with air, but the refrigeration device 200 may alternatively be configured such that refrigerant that is sealed inside exchanges heat with water, refrigerant, or fluid such as brine.

[0017]

Fig. 2 is a schematic diagram illustrating an example of a configuration of the refrigeration device provided in the refrigerant amount management system 300.

The refrigeration device 200Aand the refrigeration device 200B have the same configuration, and thus, an example configuration ofthe refrigeration device 200Awill be described here with reference to Fig. 2.

[0018]

As shown in Fig. 2, the refrigeration device 200A includes one heat source side unit 210A, and two load side units 220Aand 220B, which are connected in parallel with the heat source side unit 210A. The heat source side unit 210A, and the load side units 220A and 220B are connected by a liquid refrigerant extension pipe 6 and a gas refrigerant extension pipe 7 to form a refrigerant circuit 10 for circulating refrigerant. Refrigerant that is charged in the refrigerant circuit 10 of Embodiment 1 is R410A, which is HFC mixed refrigerant, for example.

[0019] [Heat Source Side Unit]

For example, the heat source side unit 210A includes a heat source side refrigerant circuit 10b, a first injection circuit 51, and a second injection circuit 53, which form a part of the refrigerant circuit 10, and a heat source side control unit 31. Additionally, in the following, an example where the first injection circuit 51 and the second injection circuit 53 are included will be described, but the refrigeration device 200 may alternatively include one of the first injection circuit 51 and the second injection circuit 53.

[0020]

The heat source side refrigerant circuit 10b includes a compressor 21, a heat source side heat exchanger 23, a receiver 25, a subcooler 22, a liquid side stop valve 28, a gas side stop valve 29, and an accumulator 24. That is, the heat source side unit 210A at least includes the compressor 21, the heat source side heat exchanger 23 provided on the downstream of the compressor 21, and the subcooler 22 provided on the downstream of the heat source side heat exchanger 23.

[0021]

The first injection circuit 51 is for branching a part of refrigerant that is sent from the heat source side heat exchanger 23 to the load side heat exchanger 42, to return the part of refrigerant from the heat source side refrigerant circuit 10b to an intermediate pressure portion of the compressor 21, and includes an injection amount regulating valve 52. The second injection circuit 53 is for branching a part of refrigerant that is sent from the heat source side heat exchanger 23 to the load side heat exchanger 42, to cause the part of refrigerant to flow from the heat source side refrigerant circuit 10b into a suction portion of the compressor 21, and includes a capillary tube 54 and a suction injection solenoid valve 55.

[0022]

For example, the compressor 21 is an inverter compressor, which is controlled by an inverter, and the operation frequency may be arbitrarily changed and the capacity may be changed by control by the heat source side control unit 31. The capacity here is the amount of refrigerant that is sent per unit time. Additionally, the compressor 21 may be a constant speed compressor that operates at 50 Hz or 60 Hz. Furthermore, Fig. 2 shows an example where one compressor 21 is provided, but two or more compressors 21 may be connected in parallel depending on the magnitude of load of the load side unit 220, for example.

[0023]

For example, the heat source side heat exchanger 23 is a fin-and-tube heat exchanger configured by including a heat transfer tube and a large number of fins, and functions as a condenser for condensing refrigerant. A heat source side fan 27 for sending air to the heat source side heat exchanger 23 is disposed near the heat source side heat exchanger 23. The heat source side fan 27 sends outside air sucked in from outside the heat source side unit 210Ato the heat source side heat exchanger 23. For example, the heat source side fan 27 is a centrifugal fan or a multi-blade fan, and is driven by a motor (not shown). The heat source side fan 27 is capable of regulating the amount of air to be sent to the heat source side heat exchanger 23, by being controlled by the heat source side control unit 31.

[0024]

The receiver 25 is disposed between the heat source side heat exchanger 23 and the subcooler 22, and retains surplus liquid refrigerant. Additionally, surplus liquid refrigerant occurs inside the refrigerant circuit 10 depending on the magnitude of load of the load side unit 220, a condensing temperature of refrigerant, an outside temperature, or the capacity of the compressor 21, for example.

[0025]

The subcooler 22 is for causing heat to be exchanged between refrigerant and air, and is integrally formed with the heat source side heat exchanger 23. That is, in the example of Embodiment 1, a part of the heat exchanger is configured as the heat source side heat exchanger 23, and another part as the subcooler 22. Alternatively, the subcooler 22 and the heat source side heat exchanger 23 may be separately configured. In such a case, a fan (not shown) for sending air to the subcooler 22 may be disposed near the subcooler 22.

[0026]

The liquid side stop valve 28 and a gas side stop valve 29 are each a valve which is capable of opening/closing operation, such as a ball valve, an on-off valve, or an operation valve. The capillary tube 54 may be a valve which is capable of regulating the flow rate.

[0027]

Additionally, in Fig. 2, inlets of the first injection circuit 51 and the second injection circuit 53 are connected between the subcooler 22 and the liquid side stop valve 28, but this is not restrictive. That is, the inlets of the first injection circuit 51 and the second injection circuit 53 may be connected between the receiver 25 and the subcooler 22, or to the receiver 25, or between the heat source side heat exchanger 23 and the receiver 25.

[0028] [Load Side Unit]

The load side unit 220A and the load side unit 220B have the same configuration, and thus, the same reference sign is assigned to corresponding structural members, and a description will be given on the configuration of the load side unit 220A. For example, the load side unit 220A is an indoor unit, which is installed inside a room, and includes a load side refrigerant circuit 10a forming a part of the refrigerant circuit 10, and a load side control unit 32.

[0029]

The load side refrigerant circuit 10a includes a load side expansion valve 41, and a load side heat exchanger 42. That is, the load side unit 220 includes the load side expansion valve 41 provided on the downstream of the subcooler 22, and the load side heat exchanger 42 provided on the downstream of the load side expansion valve 41. For example, the load side expansion valve 41 is an electronic expansion valve or a thermal expansion valve, and regulates the flow rate of refrigerant flowing through the load side refrigerant circuit 10a. Additionally, the load side expansion valve 41 may be disposed in the heat source side unit 210A. In the case of such a configuration, for example, the load side expansion valve 41 is disposed between the subcooler 22 and the liquid side stop valve 28 of the heat source side unit 210A. For example, the load side heat exchanger 42 is a fin-and-tube heat exchanger configured by including a heat transfer tube and a large number of fins, and functions as an evaporator for evaporating refrigerant.

[0030]

A load side fan 43 for sending air to the load side heat exchanger 42 is disposed near the load side heat exchanger 42. For example, the load side fan 43 is a centrifugal fan or a multi-blade fan, and is driven by a motor (not shown). The load side fan 43 is capable of regulating the amount of air to be sent to the load side heat exchanger 42, by being controlled by the load side control unit 32.

[0031] [Injection Circuit]

Next, a description will be given on each injection circuit. The first injection circuit 51 reduces a refrigerant temperature at a discharge portion of the compressor

21. The inlet of the first injection circuit 51 is connected between an outlet of the subcooler 22 and the liquid side stop valve 28, and a part of high-pressure liquid refrigerant subcooled by the subcooler 22 is caused to be two-phase refrigerant at an intermediate pressure by having the pressure reduced by the injection amount regulating valve 52, and is caused to flow into the injection portion of the compressor 21.

[0032]

The second injection circuit 53 reduces temperatures of a motor, refrigerating machine oil inside the compressor 21, and a refrigerant temperature at the discharge portion. The inlet of the second injection circuit 53 is connected between the outlet of the subcooler 22 and the liquid side stop valve 28, and a part of high-pressure liquid refrigerant subcooled by the subcooler 22 is caused to be two-phase refrigerant at a low pressure by having the pressure reduced by the capillary tube 54, and is caused to flow into the suction portion of the compressor 21.

[0033] [Control Unit and Sensors]

Next, a description will be given on the control unit and sensors provided in the refrigeration device 200A. The heat source side control unit 31 includes a microcomputer and a memory, for example, and controls the entire refrigeration device 200A. The load side control unit 32 includes a microcomputer and a memory, for example, and controls the load side unit 220A. The load side control unit 32 and the heat source side control unit 31 may exchange control signals through communication, and for example, the load side control unit 32 controls the load side unit 220A by receiving, from the heat source side control unit 31, a control signal indicating an instruction regarding an operation.

[0034]

The remote control 230A is connected to the load side control unit 32 of the load side unit 220A, and the remote control 230B is connected to the load side control unit 32 of the load side unit 220B. The remote control 230 transmits an operation signal according to a received input operation to the load side control unit 32. The load side control unit 32 controls the refrigeration device 200A according to the operation signal transmitted from the remote control 230 while coordinating with the heat source side control unit 31 as necessary.

[0035]

The refrigeration device 200A includes, at the heat source side unit 210A, a suction temperature sensor 33a, a discharge temperature sensor 33b, an outside air suction temperature sensor 33c, and a subcooler high-pressure side outlet temperature sensor 33d. Furthermore, the refrigeration device 200A includes, at each of the load side units 220A and 220B, a load side heat exchanger inlet temperature sensor 33e, a load side heat exchanger outlet temperature sensor 33f, and an air suction temperature sensor 33g. Moreover, the refrigeration device 200A includes, at the heat source side unit 210A, a suction pressure sensor 34a, and a discharge pressure sensor 34b.

[0036]

The suction temperature sensor 33a, the discharge temperature sensor 33b, the outside air suction temperature sensor 33c, the subcooler high-pressure side outlet temperature sensor 33d, the suction pressure sensor 34a, and the discharge pressure sensor 34b are connected to the heat source side control unit 31. The load side heat exchanger inlet temperature sensor 33e, the load side heat exchanger outlet temperature sensor 33f, and the air suction temperature sensor 33g are connected to the load side control unit 32.

[0037]

The suction temperature sensor 33a detects a temperature of refrigerant to be sucked in by the compressor 21. The discharge temperature sensor 33b detects a temperature of refrigerant that is discharged from the compressor 21. The subcooler high-pressure side outlet temperature sensor 33d detects a subcooled refrigerant temperature, which is a temperature of refrigerant that has passed through the subcooler 22. The load side heat exchanger inlet temperature sensor 33e detects an evaporating temperature of two-phase gas-liquid refrigerant flowing into the load side heat exchanger 42. The load side heat exchanger outlet temperature sensor 33f detects a temperature of refrigerant flowing out of the load side heat exchanger 42. Each of the sensors for detecting a temperature of refrigerant is installed in contact with a refrigerant pipe or is disposed inserted in a refrigerant pipe, for example.

[0038]

The outside air suction temperature sensor 33c detects an ambient temperature outside the room by detecting an outside temperature, which is the temperature of air before passing through the heat source side heat exchanger 23. The air suction temperature sensor 33g detects the ambient temperature inside the room where the load side heat exchanger 42 is installed, by detecting the temperature of air before passing through the load side heat exchanger 42.

[0039]

The suction pressure sensor 34a is disposed on the suction side of the compressor 21, and detects a suction pressure, which is the pressure of refrigerant that is sucked into the compressor 21. Additionally, the suction pressure sensor 34a only has to be disposed between the gas side stop valve 29 and the compressor 21. The discharge pressure sensor 34b is disposed on the discharge side of the compressor 21, and detects a discharge pressure, which is the pressure of refrigerant that is discharged from the compressor 21.

[0040]

Fig. 3 is a block diagram illustrating an example of a configuration of the refrigerant amount management device 100 provided in the refrigerant amount management system 300. Fig. 4 is a graph showing a relationship between fluctuations in a low-side pressure at the refrigerant circuit 10 of the refrigeration device 200 and a target low-side pressure. Fig. 5 is an explanatory diagram showing a relationship between the amount of refrigerant in the refrigeration device

200 and thermal efficiency T. Fig. 6 is a graph illustrating an example of a relationship between the thermal efficiency T and a refrigerant amount determination threshold Tm in a set period of time, in a case where the amount of refrigerant is determined by a refrigerant amount determination unit 73 to be appropriate. Fig. 7 is a schematic diagram illustrating an example of information indicating an insufficiency of refrigerant, which is displayed by a display unit 80 in a case where an insufficiency of refrigerant is determined by the refrigerant amount determination unit 73. Fig. 8 is a graph illustrating an example of a relationship between the thermal efficiency T and the refrigerant amount determination threshold Tm in a set period of time, in a case where an insufficiency of refrigerant is determined by the refrigerant amount determination unit 73.

Afunctional configuration of the refrigerant amount management device 100 will be specifically described with reference to Figs. 3 to 8.

[0041]

The refrigerant amount management device 100 manages the amount of refrigerant that is charged in the refrigerant circuit 10 formed by connecting the heat source side unit 210 and at least one load side unit 220 with a pipe. That is, the refrigerant amount management device 100 manages the amount of refrigerant that is charged in the refrigeration device 200, and in a case where a plurality of refrigeration devices 200 are connected, the refrigerant amount management device 100 manages the amount of refrigerant in each refrigeration device 200. The refrigerant amount management device 100 includes a data collection unit 60, a storage unit 70, an operation state determination unit 71, a thermal efficiency calculation unit 72, a refrigerant amount determination unit 73, an output control unit 74, a display unit 80, and a communication unit 90.

[0042]

The data collection unit 60 periodically collects, as a low-side pressure, which is the pressure on the low-pressure side of the refrigerant circuit 10, a pressure that is detected by the suction pressure sensor 34a. Moreover, the data collection unit 60 transmits the collected information about the low-side pressure to the operation state determination unit 71.

[0043]

Furthermore, the data collection unit 60 periodically collects, as refrigerant amount determination data, the subcooled refrigerant temperature detected by the subcooler high-pressure side outlet temperature sensor 33d, the outside temperature detected by the outside air suction temperature sensor 33c, and the discharge pressure detected by the discharge pressure sensor 34b. Then, the data collection unit 60 transmits the collected refrigerant amount determination data to the thermal efficiency calculation unit 72.

[0044]

The storage unit 70 stores information about the amount of refrigerant, and a control program of the refrigerant amount management device 100, for example.

The storage unit 70 stores a target low-side pressure P1 and a margin a to be used by the operation state determination unit 71 at the time of determination of whether an operation state is stable. The storage unit 70 stores a refrigerant amount determination threshold Tm to be used by the refrigerant amount determination unit 73 at the time of determination of whether there is an insufficiency of refrigerant. [0045]

The operation state determination unit 71 uses the information about the lowside pressure transmitted from the data collection unit 60 to determine whether the operation state of each refrigeration device 200 is stable. More specifically, the operation state determination unit 71 determines whether the operation state of each refrigeration device 200 is stable, by determining whether the low-side pressure is at or below a determination reference pressure P2. That is, in the case where the lowside pressure is at or below the determination reference pressure P2, the operation state determination unit 71 determines that the operation state is stable, and in the case where the low-side pressure is higher than the determination reference pressure P2, the operation state determination unit 71 determines that the operation state is unstable. When the operation state is determined to be stable, the operation state determination unit 71 transmits a calculation command to the thermal efficiency calculation unit 72.

[0046]

The configuration of the operation state determination unit 71 will be described in greater detail with reference to Fig. 4.

As shown in Fig. 4, the heat source side control unit 31 increases or reduces an operation frequency of the compressor 21 so that the actual low-side pressure approaches the target low-side pressure P1 set in advance. The low-side pressure of the compressor 21 during operation thus shifts in a state close to the target lowside pressure P1. However, for example, in the case where the temperature inside the room is high at the time of cooling down after extended stop of the refrigeration device 200, operation is possibly performed in a state where the pressure on the lowpressure side of the refrigerant circuit 10 is higher than a normal pressure.

[0047]

When operation is performed in a state where the pressure on the low-pressure side of the refrigerant circuit 10 is higher than a normal pressure, the pressure is increased between the load side expansion valve 41 and the suction portion of the compressor 21, and concentration of refrigerant is increased. A required amount of refrigerant is expressed by a product of concentration and volume, and thus, the required amount of refrigerant on the low-pressure side is temporarily increased, and a refrigerant deficiency state is reached on the high-pressure side, such as the receiver 25, the subcooler 22, and the heat source side heat exchanger 23. That is, in a state where the low-side pressure is higher to a certain extent than a normal temperature, the accuracy of refrigerant amount determination by the refrigerant amount determination unit 73 is reduced.

[0048]

Accordingly, the refrigerant amount management device 100 is configured such that refrigerant amount determination is not performed by the refrigerant amount determination unit 73 in a case where, as shown in Fig. 4, the current low-side pressure is higher than the determination reference pressure P2 obtained by adding the margin a to the target low-side pressure P1. Additionally, the target low-side pressure P1 and the margin a are set in advance and are stored in the storage unit 70, and the refrigerant amount management device 100 changes the target low-side pressure P1 and the margin a as appropriate according detection results of various sensors, for example.

[0049]

Additionally, for example, a pressure sensor may be provided at an outlet of the load side heat exchanger 42, and the data collection unit 60 may periodically collect a pressure detected by the pressure sensor as the low-side pressure, and the operation state determination unit 71 may use the low-side pressure and determine whether the operation state of each refrigeration device 200 is stable.

[0050]

The thermal efficiency calculation unit 72 periodically determines the thermal efficiency T by dividing the degree of subcooling of refrigerant at the outlet of the subcooler 22 by a maximum temperature difference, which is a difference between the condensing temperature of refrigerant and the outside temperature, and causes the determined thermal efficiency T to be stored in the storage unit 70. More specifically, the thermal efficiency calculation unit 72 converts the discharge pressure detected by the discharge pressure sensor 34b to a saturation pressure, determines the condensing temperature of refrigerant, and determines the degree of subcooling of refrigerant at the outlet of the subcooler 22 by subtracting the subcooled refrigerant temperature from the determined condensing temperature. Additionally, a temperature sensor may be disposed at the heat source side heat exchanger 23, and the thermal efficiency calculation unit 72 may use a detection temperature of the temperature sensor as the condensing temperature.

[0051]

The refrigerant amount determination unit 73 determines whether there is an insufficiency of refrigerant, based on the thermal efficiency T determined by the thermal efficiency calculation unit 72. Furthermore, the refrigerant amount determination unit 73 determines whether there is an insufficiency of refrigerant, in a case where the low-side pressure is determined by the operation state determination unit 71 to be at or below the determination reference pressure.

[0052]

The configuration of the refrigerant amount determination unit 73 will be described in greater detail with reference to Fig. 5.

In Fig. 5, a horizontal axis indicates the amount of refrigerant in the refrigeration device 200, and a vertical axis indicates the thermal efficiency T of the subcooler 22. Furthermore, a reference sign E is a critical amount of refrigerant, which is the amount of refrigerant when there is no more surplus refrigerant. As shown in Fig. 5, with the refrigeration device 200, the thermal efficiency T is reduced when the amount of refrigerant is reduced to the critical amount of refrigerant E and there is no more surplus liquid refrigerant in the receiver 25.

[0053]

Accordingly, the refrigerant amount determination unit 73 determines that there is an insufficiency of refrigerant, when the thermal efficiency T reaches or falls below the refrigerant amount determination threshold Tm. The thermal efficiency T here indicates the performance of the subcooler 22, and fluctuation thereof based on the operation condition of the refrigeration device 200 is small compared with the degree of subcooling, and the accuracy of a refrigerant amount determination process may be increased without setting the refrigerant amount determination threshold Tm for each operation condition of the refrigeration device 200. That is, the refrigerant amount determination threshold Tm is set in advance based on various operation conditions of the refrigeration device 200.

[0054]

Additionally, the refrigerant amount determination unit 73 may change the refrigerant amount determination threshold Tm according to the air volume of the heat source side fan 27; for example, the refrigerant amount determination threshold Tm may be increased when the air volume of the heat source side fan 27 is great, and the refrigerant amount determination threshold Tm may be reduced when the air volume of the heat source side fan 27 is small.

[0055]

Furthermore, information about the refrigerant amount determination threshold Tm may be held in the heat source side unit 210 or the load side unit 220, and the refrigerant amount determination unit 73 may acquire the information about the refrigerant amount determination threshold Tm from the heat source side unit 210 or the load side unit 220 at the time of determining whether there is an insufficiency of refrigerant.

[0056]

The output control unit 74 has a function of causing the display unit 80 to display information indicating the thermal efficiency T in a set period of time, which is stored in the storage unit 70. In Embodiment 1, when determination of whether there is an insufficiency of refrigerant is performed by the refrigerant amount determination unit 73, the output control unit 74 causes the display unit 80 to display, as set period-of-time data, the information indicating the thermal efficiency T and the information indicating the refrigerant amount determination threshold Tm in the set period of time.

[0057]

Information which the display unit 80 is caused to display by the output control unit 74 will be more specifically described with reference to Figs. 6 to 8. Figs. 6 to 8 are examples of the set period-of-time data that the display unit 80 is caused to display by the output control unit 74, and are time series graphs showing a relationship between indicating the thermal efficiency T and · indicating the refrigerant amount determination threshold Tm. Furthermore, in Figs. 6 and 8, cases are illustrated where the set period of time is one month. Fig. 7 shows an example of refrigerant deficiency information which the display unit 80 is caused to display by the output control unit 74 in a case where an insufficiency of refrigerant is determined by the refrigerant amount determination unit 73.

[0058]

In the case where it is determined by the refrigerant amount determination unit 73 that there is no insufficiency of refrigerant, the output control unit 74 causes the display unit 80 to display the set period-of-time data as shown in Fig. 6. In the example in Fig. 6, a case is illustrated where the output control unit 74 causes information indicating the thermal efficiency T and information indicating the refrigerant amount determination threshold Tm in the set period of time to be displayed, but such a case is not restrictive, and the output control unit 74 may alternatively cause the display unit 80 to display only the information indicating the thermal efficiency T in the set period of time as the set period-of-time data. Also in such a case, a person such as a service person is able to visually check a change in the thermal efficiency T, and excess or deficiency in the amount of refrigerant may be prevented.

[0059]

Furthermore, in the case where it is determined by the refrigerant amount determination unit 73 that there is an insufficiency of refrigerant, the output control unit 74 causes the display unit 80 to display the refrigerant deficiency information indicating that there is an insufficiency of refrigerant, as shown in Fig. 7.

[0060]

The display unit 80 here is a touch panel, for example, and displays information about the amount of refrigerant, and receives a touch operation of a person such as a service person. In the example in Fig. 7, a command button 81 for receiving an information output command is displayed at a part of the refrigerant deficiency information. When a person such as a service person touches the command button 81, an information output command is output from the display unit 80 to the output control unit 74.

[0061]

When an information output command in accordance with display of the refrigerant deficiency information is input, the output control unit 74 causes the display unit 80 to display the set period-of-time data as shown in Fig. 8. In the set period-of-time data in Fig. 8, a person such as a service person may check at first glance that indicating the thermal efficiency T shows a great reduction on October 31st.

[0062]

Furthermore, the display unit 80 includes a switch button (not shown) for receiving a display switch operation of a person such as a service person, and the output control unit 74 performs switching and display of the set period-of-time data according to a touch operation on the switch button. That is, the refrigerant amount management device 100 is capable of displaying as appropriate set period-of-time data according to a set period of time, such as set period-of-time data of an arbitrary month.

[0063]

The output control unit 74 may alternatively cause the display unit 80 to display, in the form of numerical values, the set period-of-time data including the information indicating the thermal efficiency T in the set period of time. That is, a table sorting the information about the thermal efficiency T and the refrigerant amount determination threshold Tm on the basis of one day or a unit time obtained by dividing one day may be displayed by the display unit 80 in units of one month, for example. Furthermore, display may be performed by switching the information about the thermal efficiency T and the refrigerant amount determination threshold Tm on the basis of one day or a unit time according to a touch operation on the switch button on the display unit 80, for example.

[0064]

Moreover, the output control unit 74 may cause the display unit 80 to display only the information indicating the thermal efficiency T in the set period of time. Also in such a case, a person such as a service person is able to visually check a change in the thermal efficiency T, and excess or deficiency in the amount of refrigerant may be prevented.

[0065]

Additionally, the output control unit 74 may constantly or periodically cause the display unit 80 to display the information indicating the thermal efficiency T and the information indicating the refrigerant amount determination threshold Tm in the set period of time. Furthermore, the display unit 80 may include a display command button (not shown) for receiving a display command for the set period-of-time data from a person such as a service person, and the output control unit 74 may cause the display unit 80 to display the set period-of-time data according to a touch operation on the switch button.

[0066]

The display unit 80 may be a liquid crystal panel not having the function of receiving a touch operation, for example, and in such a case, the refrigerant amount management device 100 may include an operation unit (not shown) including a physical button having the same function as at least one of the command button 81, the switch button, and the display command button. Also in such a case, when a person such as a service person presses the physical button, a command such as an information output command is output to the output control unit 74, and the output control unit 74 may perform a display process of the set period-of-time data.

[0067]

Moreover, the refrigerant amount management device 100 may further include an external contact output terminal (not shown) for information output. The output control unit 74 may transmit each piece of information to be displayed by the display unit 80 to an external appliance connected to the external contact output terminal. Furthermore, the refrigerant amount management device 100 may be mounted in the remote control 230.

[0068]

Furthermore, the output control unit 74 has a function of outputting each piece of information to be displayed by the display unit 80 to an external appliance through the communication unit 90 and a public network such as an open network and by means of an email, for example. The communication unit 90 performs information communication with the external appliance through a telephone line or a LAN line, for example.

[0069]

Additionally, the data collection unit 60, the operation state determination unit 71, the thermal efficiency calculation unit 72, the refrigerant amount determination unit

73, the output control unit 74, and the communication unit 90 may be realized by hardware such as a circuit device that realizes each function described above, or may be realized by software that is executed by a microcomputer such as a DSP or an arithmetic device such as a CPU. The storage unit 70 may be configured by a HDD (Hard Disk Drive) or a flash memory, for example.

[0070] [Explanation of Operation]

Fig. 9 is a flowchart describing an operation of the refrigerant amount management device 100 in Fig. 1. A determination process and an output process of the refrigerant amount management device 100 regarding the amount of refrigerant will be described with reference to Fig. 9.

[0071]

First, the data collection unit 60 collects information about the low-side pressure, which is the pressure on the low-pressure side of the refrigerant circuit 10, and transmits the collected information about the low-side pressure to the operation state determination unit 71 (Fig. 9: step S101). Furthermore, the data collection unit 60 collects the refrigerant amount determination data, which are pieces of information about the subcooled refrigerant temperature, the outside temperature, and the discharge pressure, and transmits the collected refrigerant amount determination data to the thermal efficiency calculation unit 72 (Fig. 9: step S102).

[0072]

Next, the operation state determination unit 71 compares the low-side pressure transmitted from the data collection unit 60 and the determination reference pressure, and thereby determines whether the operation state of the refrigeration device 200 is stable (Fig. 9: step S103). In the case where the low-side pressure is at or below the determination reference pressure, the operation state determination unit 71 determines that the operation state of the refrigeration device 200 is stable (Fig. 9: step S103, Yes), and transmits a calculation command to the thermal efficiency calculation unit 72 (Fig. 9: step S104).

[0073]

When the calculation command is received from the operation state determination unit 71, the thermal efficiency calculation unit 72 determines the thermal efficiency T by using the refrigeration amount determination data, and transmits information about the determined thermal efficiency T to the refrigerant amount determination unit 73 (Fig. 9: step S105).

At this time, the thermal efficiency T of the subcooler 22 preferably takes a moving average of a plurality of thermal efficiencies T which are temporally different from each other, instead of using an instantaneous value. By taking a moving average of a plurality of thermal efficiencies T which are temporally different from each other, stability of a refrigeration cycle may also be taken into account.

[0074]

When the information about the thermal efficiency T is transmitted from the thermal efficiency calculation unit 72, the refrigerant amount determination unit 73 compares the thermal efficiency T and the refrigerant amount determination threshold Tm, and determines whether there is an insufficiency of refrigerant (Fig. 9: step S106).

[0075]

On the other hand, in the case where the low-side pressure is higher than the determination reference pressure, the operation state determination unit 71 determines that the operation state of the refrigeration device 200 is unstable (Fig. 9: step S103, No). In this case, the refrigerant amount determination unit 73 returns to step S101 without determining whether there is an insufficiency of refrigerant.

[0076]

In the case where, due to the thermal efficiency T being at or below the refrigerant amount determination threshold Tm, the refrigerant amount determination unit 73 determines that there is an insufficiency of refrigerant (Fig. 9: step S106, Yes), the output control unit 74 causes the display unit 80 to display the refrigerant deficiency information (Fig. 9: step S107).

[0077]

The output control unit 74 maintains a state where the refrigerant deficiency information is displayed by the display unit 80, until there is an input of an information output command in accordance with display of the refrigerant deficiency information (Fig. 9: step S108, No). When an information output command in accordance with display of the refrigerant deficiency information is input (Fig. 9: step S108, Yes), the output control unit 74 causes the display unit 80 to display information indicating the thermal efficiency T in the set period of time (Fig. 9: step S109).

[0078]

On the other hand, in the case where, due to the thermal efficiency T exceeding the refrigerant amount determination threshold Tm, the refrigerant amount determination unit 73 determines that there is no insufficiency of refrigerant (Fig. 9: step S106, No), the output control unit 74 causes the display unit 80 to display the set period-of-time data (Fig. 9: step S109).

[0079]

In the case where a plurality of refrigeration devices 200 are connected to the refrigerant amount management device 100, the refrigerant amount management device 100 performs the processes described above for each refrigeration device 200. Additionally, in the explanation of the operation given above, a case is described where operation is performed in the order of the numbers assigned in Fig.

9, but such a case is not restrictive. For example, steps S101 and S102 may be simultaneously performed, or step S102 may be performed first. Furthermore, the operation in step S102 may be performed in the case where the operation state of the refrigeration device 200 is determined by the operation state determination unit 71 to be stable (Fig. 9: step S103, Yes).

[0080]

Moreover, the refrigerant amount management device 100 may perform the determination process and the output process regarding the amount of refrigerant upon reception of an instruction from a remote device (not shown). The determination process and the output process regarding the amount of refrigerant described above may be applied to a refrigerant charging operation at the time of installation of the refrigeration device 200, or to a refrigerant charging operation at the time of maintenance of the refrigeration device 200.

[0081]

As described above, the refrigerant amount management device 100 of Embodiment 1 is capable of displaying, on the display unit 80 or an external appliance, information about the thermal efficiency that accurately follows a change in the amount of refrigerant as information indicating a shift in the amount of refrigerant. Accordingly, a person such as a service person may grasp a shift in the amount of refrigerant and perform appropriate maintenance of the refrigeration device 200 by checking the display unit 80 or the external appliance, for example. As a result, with the refrigerant amount management device 100, excess or deficiency in the amount of refrigerant may be prevented, and reduction in the performance of the refrigeration device 200 and occurrence of damages to structural appliances may be suppressed. [0082]

Moreover, the refrigerant amount management device 100 performs the refrigerant amount determination process by using the thermal efficiency T whose fluctuation which is caused depending on the operation state of the refrigeration device 200 is relatively small, and thus, even if there is a leakage of refrigerant, such leakage of refrigerant may be detected at an early stage. That is, the refrigerant amount determination threshold Tm may be set higher than in the case of a conventional refrigerant amount determination process using the degree of subcooling, and the refrigerant amount management device 100 may thus rapidly perform the refrigerant amount determination process. Furthermore, since the refrigerant amount management device 100 does not perform the refrigerant amount determination process when the operation state is unstable, erroneous determination may be prevented.

[0083]

A conventional refrigeration device displays only the result indicating whether there is an insufficiency of refrigerant, and thus, a person such as a service person cannot grasp a change over time in the amount of refrigerant. Accordingly, even in the case of erroneous determination, a person such as a service person takes a measure according to the result of such erroneous determination. When a person such as a service person charges refrigerant according to erroneous determination that there is an insufficiency of refrigerant, the cost is increased due to replenishment of unnecessary refrigerant. Furthermore, in the case of occurrence of liquid back, the amount of liquid back may be increased, thereby causing a failure of the compressor. Moreover, when the amount of refrigerant is unnecessarily increased, it may take time to find out about a leakage of refrigerant. On the other hand, in the case where a person such as a service person does not charge refrigerant due to erroneous determination that the amount of refrigerant is appropriate, the performance of the refrigeration device may be reduced or damages may be caused to structural appliances due to an insufficiency of refrigerant.

[0084]

Since the refrigerant amount management device 100 causes the display unit 80 to display the set period-of-time data, the amount of refrigerant may be made clear at an early point. Particularly, in Embodiment 1, the refrigerant amount management device 100 displays information about the thermal efficiency T and information about the refrigerant amount determination threshold Tm in a set period of time in the form of a time series graph, and thus, a person such as a service person may check a shift in the amount of refrigerant at first glance.

[0085]

Modification 1>

Fig. 10 is a schematic diagram illustrating an example of a configuration of a refrigeration device according to Modification 1 of Embodiment 1. As shown in Fig. 10, a refrigeration device 200M according to Modification 1 is characteristic in that it includes a first subcooler 22A and a second subcooler 22B, instead of the subcooler 22 of the refrigeration device 200A in Fig. 2. Same structural members as those of the refrigeration device 200A will be denoted by the same reference signs, and description thereof will be omitted.

[0086]

As shown in Fig. 10, the second subcooler 22B is provided on the downstream of the first subcooler 22A configured in the same manner as the subcooler 22 described above. The second subcooler 22B includes a double pipe or plate heat exchanger, for example, and causes heat to be exchanged between high-pressure refrigerant flowing through the heat source side refrigerant circuit 10b and intermediate pressure refrigerant flowing through a first injection circuit 51 A.

[0087]

A part of refrigerant which has passed through the second subcooler 22B is expanded at the injection amount regulating valve 52 into intermediate pressure refrigerant, and exchanges heat with refrigerant that passes through the second subcooler 22B. That is, in Modification 1, the high pressure refrigerant which has flowed from the receiver 25 and exchanged heat at the second subcooler 22B is further subcooled. Furthermore, the intermediate pressure refrigerant which has flowed from the injection amount regulating valve 52 and exchanged heat at the second subcooler 22B is made into refrigerant with a high quality, and is injected into the suction side of the compressor 21 to reduce the discharge temperature of the compressor 21.

[0088]

In Modification 1, the thermal efficiency calculation unit 72 may determine, as the thermal efficiency T, thermal efficiency of the first subcooler 22A, thermal efficiency of second subcooler 22B, or thermal efficiency of the first subcooler 22A and the second subcooler 22B. Additionally, the refrigeration device 200M may be configured such that refrigerant flowing from the receiver 25 flows into the second subcooler 22B, without including the first subcooler 22A.

[0089]

Modification 2>

Fig. 11 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Modification 2 of Embodiment 1. As shown in Fig. 11, the configuration in Modification 2 is characteristic in that structural members having the same functions as the structural members provided in the refrigerant amount management device 100 described above are distributed in two different devices. That is, in Modification 2, a collection/calculation device 100A and a refrigerant amount management device 100B realize the same functions as the refrigerant amount management device 100. Same structural members as those of the refrigerant amount management device 100 will be denoted by the same reference signs, and description thereof will be omitted.

[0090]

The collection/calculation device 100A includes the data collection unit 60, a threshold storage unit 70A, the operation state determination unit 71, the thermal efficiency calculation unit 72, and a refrigerant amount determination unit 73A. The collection/calculation device 100A is connected to the refrigeration device 200. The refrigerant amount management device 100B includes the storage unit 70, an output control unit 74B, the display unit 80, and the communication unit 90.

[0091]

The refrigerant amount determination unit 73A outputs, to the output control unit 74B, information indicating the result of determination of the amount of refrigerant, information of the thermal efficiency T periodically acquired form the thermal efficiency calculation unit 72, and information about the refrigerant amount determination threshold Tm in the threshold storage unit 70A. Other configurations and operations of the refrigerant amount determination unit 73A are the same as those of the refrigerant amount determination unit 73 described above.

[0092]

The output control unit 74B causes information about the thermal efficiency T and the refrigerant amount determination threshold Tm periodically output from the refrigerant amount determination unit 73Ato be stored in the storage unit 70. Furthermore, the output control unit 74B causes the display unit 80 to display, according to a result of determination of the amount of refrigerant by the refrigerant amount determination unit 73Aor according to an information output command, information indicating the thermal efficiency T and information indicating the refrigerant amount determination threshold Tm in a set period of time. Other configurations and operations of the output control unit 74B are the same as those of the output control unit 74 described above.

[0093]

In Modification 2, an example is described where the collection/calculation device 100Aand the refrigerant amount management device 100B are provided outside the refrigeration device 200, but such a case is not restrictive, and at least one of the collection/calculation device 100Aand the refrigerant amount management device 100B may be provided in the refrigeration device 200. That is, for example, the collection/calculation device 100Amay be incorporated as an internal functional configuration of the heat source side control unit 31 or the load side control unit 32 of the refrigeration device 200. Furthermore, the refrigerant amount management device 100B may be mounted in the remote control 230, for example.

[0094]

Modification 3>

Fig. 12 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Modification 3 of Embodiment 1. As shown in Fig. 12, the configuration in Modification 3 is characteristic in that structural members having the same functions as the structural members provided in the refrigerant amount management device 100 described above are distributed in two different devices. That is, in Modification 3, a collection/calculation device 100C and a refrigerant amount management device 100D realize the same functions as the refrigerant amount management device 100. Same structural members as those of the refrigerant amount management device 100 will be denoted by the same reference signs, and description thereof will be omitted.

[0095]

The collection/calculation device 100C includes the data collection unit 60, the operation state determination unit 71, and a thermal efficiency calculation unit 72C. The refrigerant amount management device 100D includes the storage unit 70, a refrigerant amount determination unit 73D, the output control unit 74, the display unit 80, and the communication unit 90.

[0096]

The thermal efficiency calculation unit 72C periodically outputs information about determined thermal efficiency T to the refrigerant amount determination unit 73D. Furthermore, the thermal efficiency calculation unit 72C outputs a calculation command transmitted from the thermal efficiency calculation unit 72 to the refrigerant amount determination unit 73D. Other configurations and operations of the thermal efficiency calculation unit 72C are the same as those of the thermal efficiency calculation unit 72 described above.

[0097]

The refrigerant amount determination unit 73D causes information about the thermal efficiency T periodically acquired from the thermal efficiency calculation unit 72C to be stored in the storage unit 70. Furthermore, the refrigerant amount determination unit 73D determines the amount of refrigerant, when a calculation command is output from the thermal efficiency calculation unit 72C. Other configurations and operations of the refrigerant amount determination unit 73D are the same as those of the refrigerant amount determination unit 73 described above. [0098]

In Modification 3, an example is described where the collection/calculation device 100C and the refrigerant amount management device 100D are provided outside the refrigeration device 200, but such a case is not restrictive, and at least one of the collection/calculation device 100Aand the refrigerant amount management device 100B may be provided in the refrigeration device 200. That is, for example, the collection/calculation device 100Amay be incorporated as an internal functional configuration of the heat source side control unit 31 or the load side control unit 32 of the refrigeration device 200. Furthermore, the refrigerant amount management device 100B may be mounted in the remote control 230, for example.

[0099]

Additionally, in Modifications 2 and 3, structural members having the same functions as the structural members provided in the refrigerant amount management device 100 described above are distributed in two different devices, but such a case is not restrictive, and the structural members may be distributed in three or more different devices, for example.

[0100]

Embodiment 2.

Fig. 13 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Embodiment 2 of the present invention. The configuration of a refrigerant amount management device 100E according to Embodiment 2 will be described with reference to Fig. 13. Structural members the same as those of the refrigerant amount management device 100 in Embodiment 1 described above will be denoted by the same reference signs, and description thereof will be omitted. Additionally, like the refrigerant amount management device 100, the refrigerant amount management device 100E is connected to the refrigeration device 200 to form a refrigerant amount management system.

[0101]

A data collection unit 60E periodically collects a com pressor frequency, which is an operation frequency of the compressor 21. Moreover, the data collection unit 60E transmits the collected compressor frequency to a thermal efficiency calculation unit 72E as necessary. Other configurations and operations of the data collection unit 60E are the same as those of the data collection unit 60 in Embodiment 1 described above.

[0102]

In the case where the low-side pressure is determined by the operation state determination unit 71 to be at or below the determination reference pressure, the thermal efficiency calculation unit 72E acquires as instability determination data, from the heat source side unit 210 and via the data collection unit 60, at least two of pieces of information among the low-side pressure, a passing refrigerant temperature, the outside temperature, and the com pressor frequency, and causes the acquired instability determination data to be stored in the storage unit 70.

[0103]

That is, the thermal efficiency calculation unit 72E may acquire, as the instability determination data, two or three pieces of information among the low-side pressure, the passing refrigerant temperature, the outside temperature, and the compressor frequency, and may cause the instability determination data to be stored in the storage unit 70. Furthermore, the thermal efficiency calculation unit 72E may alternatively acquire all the pieces of information about the low-side pressure, the passing refrigerant temperature, the outside temperature, and the compressor frequency as the instability determination data, and may cause the instability determination data to be stored in the storage unit 70.

[0104]

The thermal efficiency calculation unit 72E acquires the instability determination data every time the low-side pressure is determined by the operation state determination unit 71 to be at or below the determination reference pressure, and causes the acquired instability determination data to be sequentially stored in the storage unit 70. Other configurations and operations of the thermal efficiency calculation unit 72E are the same as those of the thermal efficiency calculation unit 72 in Embodiment 1 described above.

[0105]

A refrigerant amount determination unit 73E determines that the operation state is stable and determines whether there is an insufficiency of refrigerant, when at least two pieces of information among current discharge pressure, passing refrigerant temperature, outside temperature, and com pressor frequency coincide with at least two pieces of information in the instability determination data, instead of when the low-side pressure is determined by the operation state determination unit 71 to be at or below the determination reference pressure. By accumulating the instability determination data in the above manner, determination of the operation state may be accurately performed even when the low-side pressure cannot be acquired due to a failure of the suction pressure sensor 34a, for example.

[0106]

Alternatively, the refrigerant amount determination unit 73E may determine whether there is an insufficiency of refrigerant, when the low-side pressure is determined by the operation state determination unit 71 to be at or below the determination reference pressure, and at least two pieces of information among current discharge pressure, passing refrigerant temperature, outside temperature, and compressor frequency coincide with at least two pieces of information in the instability determination data. By performing determination of whether the operation state is stable in two stages in the above manner and increasing the determination accuracy, occurrence of erroneous determination due to a detection error may be suppressed, for example.

[0107]

Additionally, if the thermal efficiency calculation unit 72E acquires all the pieces of information about the low-side pressure, the passing refrigerant temperature, the outside temperature, and the com pressor frequency as the instability determination data, the refrigerant amount determination unit 73E may determine whether to perform determination of whether there is an insufficiency of refrigerant, based on the number of pieces of coinciding information between the current discharge pressure, passing refrigerant temperature, outside temperature, and com pressor frequency and pieces of information in the instability determination data.

[0108]

The refrigerant amount determination unit 73E may acquire at least two pieces of information among the current discharge pressure, passing refrigerant temperature, outside temperature, and com pressor frequency from the data collection unit 60E or via the thermal efficiency calculation unit 72E. Other configurations and operations of the refrigerant amount determination unit 73E are the same as those of the refrigerant amount determination unit 73 in Embodiment 1 described above.

[0109]

Furthermore, in the case where a plurality of pieces of instability determination data are stored in the storage unit 70, the refrigerant amount determination unit 73 may sequentially check at least two pieces of information among the current discharge pressure, passing refrigerant temperature, outside temperature, and compressor frequency against at least two pieces of information in each of the plurality of pieces of instability determination data.

[0110]

The refrigerant amount management device 100E in Embodiment 2 is capable of displaying, on the display unit 80 or an external appliance, information about the thermal efficiency that accurately follows a change in the amount of refrigerant. As a result, with the refrigerant amount management device 100E, excess or deficiency in the amount of refrigerant may be prevented, and reduction in the performance of the refrigeration device 200 and occurrence of damages to structural appliances may be suppressed. Other effects are also the same as those of Embodiment 1 described above.

[0111]

Additionally, Embodiment 2 illustrates a case where the thermal efficiency calculation unit 72E uses at least two pieces of information among the low-side pressure, the passing refrigerant temperature, the outside temperature, and the compressor frequency as the instability determination data, but such a case is not restrictive, and the thermal efficiency calculation unit 72E may select as appropriate detection results of various sensors provided in the refrigeration device 200 as the instability determination data and data to be used for comparison.

[0112]

Embodiment 3.

Fig. 14 is a block diagram illustrating an example of a configuration of a refrigerant amount management device according to Embodiment 3 of the present invention. Fig. 15 is an explanatory diagram showing a relationship between a change in a most recent period and a change over time, with respect to a refrigerant amount determination process by the refrigerant amount management device in Fig. 14. The configuration of a refrigerant amount management device 100F according to Embodiment 3 will be described with reference to Figs. 14 and 15. Same structural members as those of the refrigerant amount management device 100 in

Embodiment 1 described above will be denoted by the same reference signs, and description thereof will be omitted. Additionally, like the refrigerant amount management device 100, the refrigerant amount management device 100F is connected to the refrigeration device 200 to form a refrigerant amount management system.

[0113]

A refrigerant amount determination unit 73F has a function of correcting the refrigerant amount determination threshold Tm according to a change Ci in a most recent period, which is a change in the thermal efficiency T between a reference time preceding a current time by a specific period of time and the current time. More specifically, the refrigerant amount determination unit 73F multiplies the change Ci in the most recent period by a set conversion rate to determine an amount of correction of the refrigerant amount determination threshold Tm, and corrects the refrigerant amount determination threshold Tm according to the determined amount of correction. The conversion rate is set in advance based on a change over time which is determined based on a change in the thermal efficiency in each specific period of time preceding the reference time, for example, and is stored in the storage unit 70.

[0114]

Furthermore, a correction amount table associating the change in the most recent period and the amount of correction in the refrigerant amount determination threshold Tm may be stored in the storage unit 70, and the refrigerant amount determination unit 73F may determine the amount of correction in the refrigerant amount determination threshold Tm by checking the change in the most recent period in the correction amount table, and may correct the refrigerant amount determination threshold Tm according to the determined amount of correction.

[0115]

The amount of refrigerant in the refrigeration device 200 is sometimes reduced over a specific period of half a year or one year, for example. Accordingly, the refrigerant amount determination unit 73F determines that there is an insufficiency of refrigerant, when the change in the most recent period is greater than a refrigerant amount determination reference amount obtained by adding a set amount β to the change over time determined based on the change in the thermal efficiency in each specific period of time preceding the reference time.

[0116]

In Embodiment 3, the refrigerant amount determination unit 73F causes information about the thermal efficiency T in each specific period of time to be stored in the storage unit 70. Furthermore, the refrigerant amount determination unit 73F determines the change over time by taking the average of the change in the thermal efficiency in each specific period of time preceding the reference time.

[0117]

A calculation process of the change over time by the refrigerant amount determination unit 73F will be described with reference to Fig. 15. Fig. 15 assumes that the specific period of time is set to one year, and that information about the thermal efficiency T for the past four years is stored in the storage unit 70, and shows current thermal efficiency To, thermal efficiency Ti one year before, thermal efficiency T2 one year before, thermal efficiency T3 one year before, and thermal efficiency T4 one year before. In this case, the reference time preceding a current time by a specific period of time is one year before. Moreover, Fig. 15 shows, as the change in the thermal efficiency in each specific period of time preceding the reference time, together with the change Ci in the most recent period, which is the change in the thermal efficiency T from one year before to the current time, a change C2 in the thermal efficiency T from two years before to one year before, a change C3 in the thermal efficiency T from three years before to two years before, and a change C4 in the thermal efficiency T from four years before to three years before.

[0118]

In the case of the example shown in Fig. 15, the refrigerant amount determination unit 73F calculates the average of the change C2, the change C3, and the change C4 as the change over time. Furthermore, the refrigerant amount determination unit 73F adds the set amount β to the determined amount of change over time, and determines the refrigerant amount determination reference amount. Then, the refrigerant amount determination unit 73F compares the change Ci in the most recent period and the refrigerant amount determination reference amount against each other. In the case where the change Ci in the most recent period is greater than the refrigerant amount determination reference amount, the refrigerant amount determination unit 73F determines that there is an insufficiency of refrigerant, and transmits the result of determination to the output control unit 74.

[0119]

Also in the case of receiving, from the refrigerant amount determination unit 73F, the result of refrigerant amount determination based on the change over time in the amount of refrigerant, the output control unit 74 causes the display unit 80 to display information indicating the thermal efficiency T and information indicating the refrigerant amount determination threshold Tm in the set period of time, as in Embodiment 1. Furthermore, when an insufficiency of refrigerant is determined by the refrigerant amount determination unit 73, the output control unit 74 may cause the display unit 80 to display information indicating at least the change in the most recent period and the change over time.

[0120]

Other configurations and operations of the refrigerant amount determination unit 73F are the same as those of the refrigerant amount determination unit 73 in Embodiment 1 described above. Furthermore, the data collection unit 60 and the thermal efficiency calculation unit 72 may function in the same manner as the data collection unit 60E and the thermal efficiency calculation unit 72E in Embodiment 2 described above, and the refrigerant amount determination unit 73F may have the same function as the refrigerant amount determination unit 73E in Embodiment 2. [0121]

Additionally, the refrigerant amount determination unit 73F may weight the change in the thermal efficiency in each specific period of time preceding the reference time, for example, by taking into account the number of years that have passed, and may average the amounts of change after weighting to determine the change over time. Furthermore, for example, the refrigerant amount determination unit 73F may use, as the change over time, the change in the thermal efficiency T from a set period of time prior to the reference time to the reference time, such as the change C2.

[0122]

The refrigerant amount management device 100F in Embodiment 3 is capable of displaying, on the display unit 80 or an external appliance, information about the thermal efficiency that accurately follows a change in the amount of refrigerant. As a result, with the refrigerant amount management device 100F, excess or deficiency in the amount of refrigerant may be prevented, and reduction in the performance of the refrigeration device 200 and occurrence of damages to structural appliances may be suppressed. Other effects are also the same as those of Embodiments 1 and 2 described above.

[0123]

Each embodiment described above is a preferred specific example of the refrigerant amount management device and the refrigerant amount management system, and the technical scope of the present invention is not limited to such embodiments. For example, combinations of structural elements are not limited to the combinations in each embodiment described above, and the refrigerant amount management device and the refrigerant amount management system may be configured by application or replacement of a structural element described in one embodiment to or by a structural element in another embodiment. Furthermore, a structural element the position of which is not particularly specified may be disposed at any position where the function of the structural element may be realized, without being restricted to the position disclosed in each embodiment. Moreover, the shape, size, position and the like of each structure in each drawing may be changed as appropriate within the scope of the present invention. Furthermore, the relationship between the sizes of structural members or between various pieces of data in each drawing may be different from the actual relationship. Moreover, the level of temperature, pressure or the like is not set relative to an absolute value, and is relatively set according to the installation environment or the operation state of the refrigerant amount management device and the refrigerant amount management system, for example.

Reference Signs List [0124] liquid refrigerant extension pipe 7 gas refrigerant extension pipe 10 refrigerant circuit 10a load side refrigerant circuit 10b heat source side refrigerant circuit 21 compressor 22 subcooler 22A first subcooler

22B second subcooler 23 heat source side heat exchanger 24 accumulator 25 receiver 27 heat source side fan 28 liquid side stop valve gas side stop valve 31 heat source side control unit 32 load side control unit 33a suction temperature sensor 33b discharge temperature sensor 33c outside air suction temperature sensor 33d subcooler highpressure side outlet temperature sensor 33e load side heat exchanger inlet temperature sensor 33f load side heat exchanger outlet temperature sensor

33g air suction temperature sensor 34a suction pressure sensor 34b discharge pressure sensor 41 load side expansion valve 42 load side heat exchanger 43 load side fan 51 first injection circuit 51A first injection circuit 52 injection amount regulating valve 53 second injection circuit 54 capillary tube 55 suction injection solenoid valve 60, 60E data collection unit 70 storage unit 70A threshold storage unit 71 operation state determination unit

72, 72C thermal efficiency calculation unit 72E thermal efficiency calculation unit 73, 73A, 73D, 73E, 73F refrigerant amount determination unit

74, 74B output control unit 80 display unit 81 command button 90 communication unit 100 refrigerant amount management device 100A collection/calculation device 100B refrigerant amount management device

100C collection/calculation device 100D refrigerant amount management device 100E refrigerant amount management device 100F refrigerant amount management device 200 refrigeration device 200A refrigeration device

200B refrigeration device 200M refrigeration device 210, 210A,

OB heat source side unit 220, 220A, 220B, 220C, 220D load side unit

230, 230A, 230B, 230C, 230D remote control 300 refrigerant amount

management system	Ci amount of change in most recent period E critical
amount of refrigerant	P1 target low-side pressure P2 determination
5 reference pressureT	thermal efficiency Tm refrigerant amount determination
threshold

Claims

CLAIMS [Claim 1]

A refrigerant amount management device for managing an amount of refrigerant that is charged in a refrigerant circuit that is formed by connecting, by pipes, a heat source side unit including a compressor, a heat source side heat exchanger provided on a downstream of the compressor, and a subcooler provided on a downstream of the heat source side heat exchanger, and at least one load side unit including a load side expansion valve provided on a downstream of the subcooler, and a load side heat exchanger provided on a downstream of the load side expansion valve, the refrigerant amount management device comprising:

a storage unit configured to store information about the amount of the refrigerant;

a thermal efficiency calculation unit configured to periodically determine thermal efficiency by dividing a degree of subcooling of the refrigerant at an outlet of the subcooler by a maximum temperature difference that is a difference between a condensing temperature of the refrigerant and an outside temperature, and store the determined thermal efficiency in the storage unit;

a display unit configured to display the information about the amount of the refrigerant; and an output control unit having a function of displaying information on the display unit, stored in the storage unit, indicating the thermal efficiency in a set period of time. [Claim 2]

The refrigerant amount management device of claim 1, further comprising a refrigerant amount determination unit configured to determine whether the amount of the refrigerant is insufficient, based on the thermal efficiency determined by the thermal efficiency calculation unit, wherein when determination of whether the amount of the refrigerant is insufficient is performed by the refrigerant amount determination unit, the output control unit displays the information indicating the thermal efficiency in the set period of time on the display unit.

[Claim 3]

The refrigerant amount management device of claim 2, wherein, in a case where an insufficiency of the refrigerant is determined by the refrigerant amount determination unit, the output control unit displays information indicating the insufficiency of the refrigerant on the display unit, and when there is an input of a display command in accordance with display of the information, the output control unit displays the information indicating the thermal efficiency in the set period of time on the display unit.

[Claim 4]

The refrigerant amount management device of claim 2 or 3, wherein, in a case where no insufficiency of the refrigerant is determined by the refrigerant amount determination unit, the output control unit displays the information indicating the thermal efficiency in the set period of time on the display unit.

[Claim 5]

The refrigerant amount management device of any one of claims 2 to 4, wherein, in a case where the thermal efficiency determined by the thermal efficiency calculation unit is at or below a refrigerant amount determination threshold, the refrigerant amount determination unit determines that the amount of the refrigerant is insufficient.

[Claim 6]

The refrigerant amount management device of claim 5, wherein the refrigerant amount determination unit corrects the refrigerant amount determination threshold according to a change in a most recent period, the change being a change in the thermal efficiency in a period from a reference time preceding a current time by a specific period of time to the current time.

[Claim 7]

The refrigerant amount management device of claim 6, wherein a conversion rate for converting the change in the most recent period to an amount of correction in the refrigerant amount determination threshold is stored in the storage unit, and the refrigerant amount determination unit determines the amount of correction by multiplying the change in the most recent period by the conversion rate, and corrects the refrigerant amount determination threshold according to the amount of correction.

[Claim 8]

The refrigerant amount management device of claim 6, wherein a correction amount table associating the change in the most recent period and the amount of correction in the refrigerant amount determination threshold is stored in the storage unit, and the refrigerant amount determination unit determines the amount of correction by checking the change in the most recent period in the correction amount table, and corrects the refrigerant amount determination threshold according to the amount of correction.

[Claim 9]

The refrigerant amount management device of any one of claims 5 to 8, wherein information about the refrigerant amount determination threshold is held in the heat source side unit or the load side unit, and the refrigerant amount determination unit acquires the information about the refrigerant amount determination threshold from the heat source side unit or the load side unit at a time of determining whether the amount of the refrigerant is insufficient. [Claim 10]

The refrigerant amount management device of any one of claims 5 to 9, wherein, when determination of whether the amount of the refrigerant is insufficient is performed by the refrigerant amount determination unit, the output control unit displays information indicating the refrigerant amount determination threshold, together with the information indicating the thermal efficiency in the set period of time, on the display unit.

[Claim 11]

The refrigerant amount management device of any one of claims 5 to 10, wherein the refrigerant amount determination unit has a function of determining an insufficiency of the refrigerant in a case where a change in a most recent period that is a change in the thermal efficiency from a reference time preceding a current time by a specific period of time to the current time is greater than a refrigerant amount determination reference amount obtained by adding a set amount to a change over time determined based on the change in the thermal efficiency in each specific period of time preceding the reference time.

[Claim 12]

The refrigerant amount management device of claim 11, wherein the output control unit displays, on the display unit, at least information indicating the change in the most recent period and the change over time, when an insufficiency of the refrigerant is determined by the refrigerant amount determination unit.

[Claim 13]

The refrigerant amount management device of any one of claims 2 to 12, further comprising an operation state determination unit configured to determine whether a low-side pressure of the refrigerant circuit is at or below a determination reference pressure, wherein in a case where the low-side pressure is determined by the operation state determination unit to be at or below the determination reference pressure, the refrigerant amount determination unit determines whether the amount of the refrigerant is insufficient.

[Claim 14]

The refrigerant amount management device of claim 13, wherein the thermal efficiency calculation unit has a function of acquiring from the heat source side unit, in a case where the low-side pressure is determined by the operation state determination unit to be at or below the determination reference pressure, at least two pieces of information, as instability determination data, among a discharge pressure that is a pressure of the refrigerant discharged from the compressor, a passing refrigerant temperature that is a temperature of the refrigerant after passing through the subcooler, the outside temperature that is a temperature of air before passing through the heat source side heat exchanger, and a compressor frequency that is an operation frequency of the compressor, and of causing the acquired instability determination data to be stored in the storage unit, and the refrigerant amount determination unit determines whether the amount of the refrigerant is insufficient, when the low-side pressure is determined by the operation state determination unit to be at or below the determination reference pressure, and at least two pieces of information among the discharge pressure, the passing refrigerant temperature, the outside temperature, and the compressor frequency at a current time coincide with at least two pieces of information in the instability determination data.

[Claim 15]

The refrigerant amount management device of any one of claims 2 to 12, further comprising an operation state determination unit configured to determine whether a low-side pressure that is a pressure of the refrigerant sucked into the compressor is at or below a determination reference pressure, wherein the thermal efficiency calculation unit has a function of acquiring from the heat source side unit, in a case where the low-side pressure is determined by the operation state determination unit to be at or below the determination reference pressure, at least two pieces of information, as instability determination data, among a discharge pressure that is a pressure of the refrigerant discharged from the compressor, a passing refrigerant temperature that is a temperature of the refrigerant after passing through the subcooler, the outside temperature that is a temperature of air before passing through the heat source side heat exchanger, and a compressor frequency that is an operation frequency of the compressor, and of causing the acquired instability determination data to be stored in the storage unit, and the refrigerant amount determination unit determines whether the amount of the refrigerant is insufficient, when at least two pieces of information among the discharge pressure, the passing refrigerant temperature, the outside temperature, and the compressor frequency at a current time coincide with at least two pieces of information in the instability determination data.

[Claim 16]

The refrigerant amount management device of any one of claims 1 to 15, wherein the output control unit displays, on the display unit, the information indicating the thermal efficiency in the set period of time in a form of a time series graph.

[Claim 17]

The refrigerant amount management device of any one of claims 1 to 16, wherein the refrigerant amount management device is mounted in a remote control, connected to the load side unit, for receiving an input operation regarding airconditioning control.

[Claim 18]

The refrigerant amount management device of any one of claims 1 to 17, wherein the output control unit has a function of outputting each piece of information to be displayed by the display unit to an external appliance through a public network. [Claim 19]

The refrigerant amount management device of any one of claims 1 to 18, further comprising an external contact output terminal for information output, wherein the output control unit has a function of transmitting each piece of information to be displayed by the display unit to an external appliance connected to the external contact output terminal.

[Claim 20]

A refrigerant amount management system comprising:

at least one refrigeration device including a refrigerant circuit that is formed by connecting, by pipes, a heat source side unit including a compressor, a heat source side heat exchanger provided on a downstream of the compressor, and a subcooler provided on a downstream of the heat source side heat exchanger, and at least one load side unit including a load side expansion valve provided on a downstream of the subcooler, and a load side heat exchanger provided on a downstream of the load side expansion valve; and the refrigerant amount management device, of any one of claims 1 to 19, for managing an amount of the refrigerant that is charged in the refrigerant circuit of the refrigeration device.