JP7066053B2 - Heat source side unit and refrigeration cycle device equipped with it - Google Patents

Description

The present disclosure relates to a heat source side unit and a refrigeration cycle device including the unit.

Japanese Patent No. 6289727 (Patent Document 1) discloses a refrigerating apparatus provided with means for filling a refrigerant circuit with an appropriate amount of refrigerant in a short time. Specifically, the control device provided in this refrigerating device notifies the notification unit to change the filling speed of the refrigerant based on the temperature efficiency of the supercooling heat exchanger. Here, the temperature efficiency is a value obtained by dividing the degree of supercooling of the refrigerant at the outlet of the supercooling heat exchanger by the maximum temperature difference of the supercooling heat exchanger.

Japanese Patent No. 6289727

In the refrigerating apparatus disclosed in the above patent document, there is a problem that the calculation error of the temperature efficiency increases under the operating conditions where the maximum temperature difference of the supercooled heat exchanger is about the same as the detection accuracy of the temperature sensor. was there. Therefore, depending on the operating conditions, it may not be possible to determine whether or not the filling amount of the refrigerant is appropriate.

The present disclosure relates to solving the above problems. One of the objects of the present disclosure is to provide a heat source side unit capable of shortening the time of the refrigerant filling work by accurately determining whether or not the filling amount of the refrigerant is appropriate, and a refrigerating cycle device including the unit. ..

The heat source side unit of one embodiment is connected to the load side unit to form a refrigeration cycle device. The load-side unit includes a refrigerant expansion mechanism and an evaporator. The heat source side unit includes a compressor, a condenser, a bypass circuit, a refrigerant amount detector, and a control device. At least the expansion mechanism, the evaporator, the compressor, and the condenser constitute a refrigerant circuit that circulates the refrigerant in order. The bypass circuit is configured to return some of the refrigerant on the outlet side of the condenser to the compressor without passing through the evaporator. The refrigerant amount detector includes a heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and a refrigerant before being heated by the heater. Includes preheating temperature sensor to detect temperature. The control device calculates the difference between the temperature detected by the temperature sensor after heating and the temperature detected by the temperature sensor before heating as the amount of temperature rise. When filling the refrigerant circuit with refrigerant, the control device instructs to fill additional refrigerant when the amount of temperature rise is equal to or greater than the first threshold value. The controller is instructed to reduce the filling rate of the additional refrigerant when the temperature rise is less than the second threshold, which is greater than the first threshold, as compared to when the temperature rise is greater than or equal to the second threshold. do.

According to the above-mentioned heat source side unit, it is determined whether or not to fill the refrigerant circuit with the refrigerant based on the amount of temperature rise, and the filling speed of the additional refrigerant is changed. As a result, it is possible to accurately determine whether or not the filling amount of the refrigerant is appropriate, and the time for the refrigerant filling work can be shortened.

It is an overall block diagram of the refrigerating apparatus which uses the heat source side unit according to Embodiment 1 of this disclosure. It is a block diagram which shows an example of the structure of a control device. It is a figure explaining the change of the refrigerant temperature by a heater in the state which the filling of the refrigerant has just started. It is a figure explaining the change of the refrigerant temperature by a heater in the state of being filled to an appropriate amount of a refrigerant. It is a figure explaining the difference of the temperature rise amount according to the charge amount of a refrigerant. It is a flowchart which shows the procedure of filling the refrigerant circuit with the refrigerant in the refrigerating apparatus of FIG. It is a timing diagram for demonstrating an example of averaging of temperature data. It is a flowchart which shows the procedure of step S210 of FIG. 6 in more detail. It is a figure which shows schematic structure of the heat source side unit 2 of a refrigerating apparatus 1. It is a figure for demonstrating the method for determining the suitability of other refrigerant filling amount. FIG. 3 is an overall configuration diagram of a refrigerating apparatus in which a heat source side unit according to the second embodiment is used. It is a figure which shows the operation pattern of a solenoid valve 79 and a heater 72. It is a flowchart which shows the procedure of filling the refrigerant circuit RC with the refrigerant in the refrigerating apparatus of FIG. It is a flowchart which shows the procedure which determines the failure of the heater in the refrigerant amount detection part. It is a flowchart which shows the procedure which performs the failure determination of a solenoid valve. FIG. 3 is an overall configuration diagram of a refrigerating apparatus in which a heat source side unit according to the third embodiment is used. It is a flowchart which shows the procedure of filling the refrigerant circuit RC with the refrigerant in the refrigerating apparatus of FIG. It is a flowchart which shows the detailed procedure of the step S194 which sets the threshold value of FIG. It is a figure for demonstrating the calculation method of enthalpy. It is a flowchart which shows the switching procedure of the filling rate in the additional filling in Embodiment 4.

Hereinafter, each embodiment will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but it is planned from the beginning of the application to appropriately combine the configurations described in the respective embodiments. In some cases, the same or corresponding parts are designated by the same or similar reference numerals, and the description thereof may not be repeated.

Embodiment 1.
[Overall configuration of refrigeration equipment]
FIG. 1 is an overall configuration diagram of a refrigerating apparatus using a heat source side unit according to the first embodiment of the present disclosure. It should be noted that the overall configuration diagram of FIG. 1 functionally shows the connection relationship and the arrangement configuration of each device in the refrigerating apparatus, and does not necessarily show the arrangement in the physical space.

With reference to FIG. 1, the refrigerating apparatus 1 includes a heat source side unit 2 and a load side unit 3. The heat source side unit 2 includes a compressor 10, a condenser 20, a fan 22, a liquid receiver 30, a supercooling heat exchanger 40, a fan 42, a sight glass 45, and pipes 80 to 83, 85. including. The heat source side unit 2 further includes pipes 86 and 87, a refrigerant amount detection unit 70, pressure sensors 90 and 92, and a control device 100.

The heat source side unit 2 further includes a temperature sensor for detecting the outlet temperature OT of the supercooled heat exchanger 40, a temperature sensor for detecting the condensation temperature CT, and a temperature sensor for detecting the outside air temperature AT. .. In the case of FIG. 1, the temperature sensor for detecting the outside air temperature AT is provided at the outside air suction port to the condenser 20. A temperature sensor for detecting the condensation temperature CT is provided on the outlet side of the condenser 20. The heat source side unit 2 further includes a temperature sensor for detecting the evaporation temperature ET. In the case of FIG. 1, the temperature sensor for detecting the evaporation temperature ET is provided inside the evaporator 60.

The evaporation temperature ET may be calculated by converting the suction pressure LP of the compressor 10 detected by the pressure sensor 90 into the refrigerant saturated gas temperature. Similarly, the condensation temperature CT may be calculated by converting the discharge pressure HP of the compressor 10 detected by the pressure sensor 92 into the refrigerant saturated liquid temperature.

The load-side unit 3 includes an expansion valve 50, an evaporator 60, a fan 62, and a pipe 84. The load side unit 3 is connected to the heat source side unit 2 through the liquid extension pipe 910 and the gas extension pipe 900. The liquid extension pipe 910 and the gas extension pipe 900 are also referred to as a first pipe and a second pipe, respectively. Further, the liquid extension pipe 910 and the gas extension pipe 900 include the heat source side unit 2 and the load side unit 3 when the refrigerating device 1 is installed in the field or when the heat source side unit 2 is newly attached to the existing load side unit 3. Since it is a pipe connected between the two, it is also called a local connection pipe. In FIG. 1, the liquid extension pipe 910 is a part of the pipe 83 from the outlet side of the supercooling heat exchanger 40 to the expansion valve 50. The gas extension pipe 900 is a part of the pipe 85 from the outlet side of the evaporator 60 to the suction port of the compressor 10.

The heat source side unit 2 may be divided into a plurality of subunits. For example, the condenser 20 and the supercooling heat exchanger 40 constitute the first subunit, and the compressor 10, the liquid receiver 30, the refrigerant amount detector 70, and the control device 100 constitute the second subunit. You may. The liquid receiving device 30 may be provided in the first subunit instead of the second subunit. Alternatively, the heat source side unit 2 and the load side unit 3 may be configured as one unit. Therefore, the term "unit" above is a term for convenience and does not necessarily mean that it is contained in one housing.

The pipe 80 connects the discharge port of the compressor 10 and the condenser 20. The pipe 81 connects the condenser 20 and the liquid receiver 30. The pipe 82 connects the liquid receiver 30 and the supercooling heat exchanger 40. The pipe 83 connects the supercooling heat exchanger 40 and the expansion valve 50. The pipe 84 connects the expansion valve 50 and the evaporator 60. The pipe 85 connects the evaporator 60 and the suction port of the compressor 10. The pipe 86 connects the pipe 82 and the refrigerant amount detection unit 70. The pipe 87 connects the refrigerant amount detection unit 70 and the pipe 85.

Through the above piping, a refrigerant circuit RC in which the refrigerant circulates in the order of the compressor 10, the condenser 20, the liquid receiver 30, the supercooling heat exchanger 40, the expansion valve 50, and the evaporator 60 is configured.

The compressor 10 compresses the refrigerant sucked from the pipe 85 and discharges the compressed refrigerant to the pipe 80. The compressor 10 is configured to adjust the rotation speed according to a control signal from the control device 100. By adjusting the rotation speed of the compressor 10, the circulation amount of the refrigerant is adjusted, and the capacity of the refrigerating device 1 can be adjusted. Various types of compressors can be adopted as the compressor 10, and for example, a compressor such as a scroll type, a rotary type, or a screw type can be adopted.

The condenser 20 condenses the refrigerant that has flowed in from the compressor 10 through the pipe 80. The refrigerant condensed in the condenser 20 flows into the pipe 81. The condenser 20 is configured such that a high-temperature and high-pressure gas refrigerant discharged from the compressor 10 exchanges heat (heat is dissipated) with outside air or the like. By this heat exchange, the refrigerant is condensed and changed into a liquid phase. The fan 22 supplies the outside air to the condenser 20 through which the refrigerant exchanges heat in the condenser 20. By adjusting the rotation speed of the fan 22, the refrigerant pressure (high pressure side pressure) on the output side of the compressor 10 can be adjusted.

The liquid receiver 30 stores the high-pressure liquid refrigerant condensed by the condenser 20. The supercooling heat exchanger 40 is configured such that the liquid refrigerant flowing from the liquid receiver 30 through the pipe 82 further exchanges heat (heat dissipation) with the outside air or the like. The refrigerant becomes a supercooled liquid refrigerant by passing through the supercooled heat exchanger 40. The fan 42 supplies the outside air through which the refrigerant exchanges heat in the supercooling heat exchanger 40 to the supercooling heat exchanger 40. The fans 22, 42, the condenser 20, and the supercooling heat exchanger 40 are often configured integrally. The sight glass 45 is a window for visually confirming air bubbles (flash gas) in the refrigerant flowing through the pipe 83.

The expansion valve 50 decompresses the refrigerant flowing from the supercooling heat exchanger 40 through the pipe 83. The refrigerant decompressed by the expansion valve 50 flows into the pipe 84. When the opening degree of the expansion valve 50 is changed in the closing direction, the refrigerant pressure on the outlet side of the expansion valve 50 decreases, and the dryness of the refrigerant increases. When the opening degree of the expansion valve 50 is changed in the opening direction, the refrigerant pressure on the outlet side of the expansion valve 50 increases, and the dryness of the refrigerant decreases. A capillary tube may be used instead of the expansion valve 50. In this disclosure, the expansion valve and the capillary tube are collectively referred to as an expansion mechanism.

The evaporator 60 evaporates the refrigerant that has flowed in from the expansion valve 50 through the pipe 84. The refrigerant vaporized in the evaporator 60 flows into the pipe 85. The evaporator 60 is configured such that the refrigerant decompressed by the expansion valve 50 exchanges heat (endothermic) with the air in the load side unit 3. The refrigerant evaporates as it passes through the evaporator 60 and becomes superheated steam. The fan 62 supplies the outside air through which the refrigerant exchanges heat in the evaporator 60 to the evaporator 60.

The refrigerant amount detecting unit 70 is provided between the pipe 86 branching from the pipe 82 and the pipe 87 connected to the pipe 85. The pipe 86, the refrigerant amount detection unit 70, and the pipe 87 constitute a “bypass circuit BC” that returns a part of the refrigerant on the outlet side of the condenser 20 to the compressor 10 without passing through the load side unit 3. Therefore, one end of the bypass circuit BC is connected between the liquid receiver 30 and the supercooled heat exchanger 40.

The refrigerant amount detection unit 70 includes a capillary tube 71, a heater 72, and temperature sensors 73 and 74. In this disclosure, a mechanism for heating a refrigerant passing through a pipe 87, such as a heater 72, is also collectively referred to as a heater. The temperature sensor 73 is also referred to as a pre-heating temperature sensor, and the temperature sensor 74 is also referred to as a post-heating temperature sensor.

The capillary tube 71 is connected between the pipe 86 and the pipe 87, and reduces the pressure of the refrigerant flowing in the bypass circuit BC. When the liquid refrigerant is supplied from the pipe 86, the capillary tube 71 is a gas-liquid two-phase so that the refrigerant that has passed through the capillary tube 71 is heated by the heater 72 without becoming a gas single phase. It is appropriately designed in consideration of the amount of heating. An expansion valve may be used instead of the capillary tube 71.

The heater 72 and the temperature sensors 73 and 74 are provided in the pipe 87. The heater 72 heats the refrigerant that has passed through the capillary tube 71. The enthalpy of the refrigerant is increased by being heated by the heater 72. As described above, the heater 72 has a two-phase gas-liquid phase without becoming a gas single phase even when the refrigerant that has passed through the capillary tube 71 is heated by the heater 72. Set. The heater 72 may heat the refrigerant from the outside of the pipe 87, or may be installed inside the pipe 87 in order to more reliably transfer heat from the heater 72 to the refrigerant.

The temperature sensor 73 detects the refrigerant temperature before the heater 72 heats the refrigerant, that is, the temperature T1 of the refrigerant between the capillary tube 71 and the heater 72, and outputs the detected value to the control device 100. On the other hand, the temperature sensor 74 detects the refrigerant temperature after the refrigerant is heated by the heater 72, that is, the temperature T2 of the refrigerant downstream of the heater 72 and before joining the pipe 85, and outputs the detected value to the control device 100. do. The temperature sensors 73 and 74 may be installed outside the pipe 87, or may be installed inside the pipe 87 in order to more reliably detect the temperature of the refrigerant.

The refrigerant amount detecting unit 70 having the above configuration can determine the suitability of the amount of the refrigerant charged in the refrigerant circuit RC. The principle and specific method will be described in detail later.

The pressure sensor 90 detects the pressure LP of the refrigerant in the pipe 85 and outputs the detected value to the control device 100. That is, the pressure sensor 90 detects the refrigerant pressure on the suction side of the compressor 10 (that is, the low pressure side pressure LP). The pressure sensor 92 detects the pressure HP of the refrigerant in the pipe 80 and outputs the detected value to the control device 100. That is, the pressure sensor 92 detects the refrigerant pressure on the discharge side of the compressor 10 (that is, the high pressure side pressure HP).

The control device 100 executes control of each device in the heat source side unit 2. As an example, the control device 100 is configured based on a computer including a CPU (Central Processing Unit) 102 and a memory 104.

FIG. 2 is a block diagram showing an example of the configuration of the control device. With reference to FIG. 2, the control device 100 includes a CPU 102, a memory 104, a storage 106, and interfaces (I / F) 108 to 114. The output device 120 and the input device 122 are connected to the control device 100 via the interfaces 108 and 110. Further, the control device 100 outputs a control signal to the compressor 10 via the interface 112. Further, the control device 100 receives the detected values from various sensors such as the temperature sensors 73 and 74 and the pressure sensors 90 and 92 via the interface 114.

The memory 104 is a non-volatile memory used as the main memory of the CPU 102. The memory 104 is also referred to as a RAM (Random Access Memory). The storage 106 is a non-volatile memory and includes a ROM (Read Only Memory) and an external storage device such as a hard disk.

The CPU 102 expands the program stored in the storage 106 into the memory 104 and executes it. The processing procedure of the control device 100 is described in the program stored in the storage 106. The CPU 102 executes control of each device in the heat source side unit 2 according to this program.

The output device 120 is a peripheral device for receiving data or a control signal from the CPU 102, outputting the data or a control signal to the outside, or notifying the user. Examples of the output device 120 include a display, a printer, a speaker, and the like. Further, the output device 120 may be an LED (Light Emitting Diode) provided on the substrate. Further, the output device 120 may be an output circuit that outputs a relay signal.

The input device 122 is a peripheral device for inputting data or a control signal to the CPU 102 inside the control device 100. Examples of the input device 122 include a keyboard, a mouse, a touch panel, and the like. Further, the output device 120 may be a push switch, a slide switch, or a rotary switch provided on the substrate.

The processing by the control device 100 is not limited to software processing by a computer, but may be realized by hardware processing by an electronic circuit. Further, it may be realized by a combination of software processing and hardware processing. The electronic circuit can be configured by FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or the like.

[Principle for determining the suitability of the refrigerant charge]
Hereinafter, the principle of determining the appropriateness of the refrigerant filling amount by using the refrigerant amount detecting unit 70 when the refrigerant circuit RC is newly filled with the refrigerant from an empty state will be described. For example, a case where a refrigerating device 1 is newly installed in the field, or a case where a new heat source side unit 2 is connected to an existing load side unit 3 such as a refrigerator or a showcase is assumed.

FIG. 3 is a diagram illustrating a change in the refrigerant temperature due to the heater in a state where the refrigerant has just started to be filled and the refrigerant is insufficient. FIG. 3A is a diagram conceptually showing the state of the refrigerant around the heater 72. FIG. 3B is a diagram showing an example of a change in the refrigerant temperature due to the heater 72.

With reference to FIG. 1 and FIG. 3A, when the filling of the refrigerant is started, the refrigerant is in a gas-liquid two-phase state at the outlet of the condenser 20 due to a shortage of the refrigerant, and the receiver 30 is in a gas-liquid two-phase state. , Liquid refrigerant is not accumulated. As a result, the gas-liquid two-phase refrigerant flows through the pipe 86, the refrigerant that has passed through the capillary tube 71 has a large gas component, and the mass flow rate of the refrigerant decreases.

With reference to FIG. 3B, the horizontal axis indicates the position of the pipe 87 in the extension direction, and P1 and P2 indicate the positions where the temperature sensors 73 and 74 are installed, respectively. The vertical axis shows the refrigerant temperature at each position of the pipe 87.

As shown in FIG. 3B, the refrigerant that has passed through the capillary tube 71 has a large amount of gas components and the mass flow rate of the refrigerant decreases. Therefore, when the refrigerant is heated by the heater 72, the temperature of the refrigerant rises. That is, the temperature T2 of the refrigerant after heating the refrigerant by the heater 72 is higher than the temperature T1 of the refrigerant before heating the refrigerant by the heater 72. In the following description, T2-T1 is referred to as a temperature rise amount. The amount of temperature rise in the case of FIG. 3B is ΔTo.

FIG. 4 is a diagram illustrating a change in the refrigerant temperature due to the heater in a state where the refrigerant is filled to an appropriate amount. FIG. 4A is a diagram conceptually showing the state of the refrigerant around the heater 72. FIG. 4B is a diagram showing an example of a change in the refrigerant temperature due to the heater 72.

With reference to FIG. 1 and FIG. 4A, when the refrigerant is filled to an appropriate amount, the refrigerant is almost liquid-phased at the outlet of the condenser 20, and the liquid refrigerant is accumulated in the receiver 30. As a result, the liquid refrigerant flows through the pipe 86, and the refrigerant that has passed through the capillary tube 71 is in a state of having a large amount of liquid components. Then, the refrigerant that has passed through the capillary tube 71 is heated by the heater 72 to increase the dryness.

With reference to FIG. 4B, the horizontal axis indicates the position of the pipe 87 in the extension direction, and P1 and P2 indicate the positions where the temperature sensors 73 and 74 are installed, respectively. The vertical axis shows the refrigerant temperature at each position of the pipe 87. Note that FIG. 4B shows a case where the refrigerant has a single boiling point, that is, a case where it is a single component refrigerant or an azeotropic mixed refrigerant.

As shown in FIG. 4B, since the refrigerant that has passed through the capillary tube 71 has a large amount of liquid components and a large mass flow rate of the refrigerant, the temperature of the refrigerant basically changes even if the refrigerant is heated by the heater 72. do not. This is because the heating energy is used to change the latent heat of the refrigerant. Therefore, the temperature T2 of the refrigerant after heating the refrigerant by the heater 72 is substantially the same as the temperature T1 of the refrigerant before heating the refrigerant by the heater 72. That is, the amount of temperature rise (T2-T1) is almost 0.

Although not particularly shown, in the case of a non-azeotropic mixed refrigerant having a plurality of boiling points, the temperature of the refrigerant is slightly increased by heating by the heater 72 even when the filling amount of the refrigerant is appropriate. However, the amount of temperature rise is at most about 10 ° C. Therefore, by adjusting the heating amount by the heater 72, it is possible to distinguish between the temperature rise of the refrigerant when the filling amount is insufficient and the temperature rise of the refrigerant when the filling amount is appropriate.

FIG. 5 is a diagram illustrating a difference in the amount of temperature rise depending on the amount of the refrigerant charged. In the example of FIG. 5, the amount of the liquid refrigerant accumulated in the receiver 30 increases in the order of FIGS. 5 (A) to 5 (C). Therefore, the ratio of the liquid component of the refrigerant that has passed through the capillary tube 71 of the pipe 86 increases in the order of FIGS. 5 (A) to 5 (C).

In the case of FIG. 5A in which the ratio of the liquid component is the smallest, the dryness of the refrigerant becomes 1 at the position Pa relatively close to the position P1 by heating the refrigerant by the heater 72. In the region closer to the position P2 than the position Pa, the temperature of the refrigerant rises due to the heating by the heater 72. As a result, the amount of the upper temperature layer at the position P2 is ΔTa. The temperature rise amount ΔTa is smaller than ΔTo in the case of FIG. 3 (B).

In the case of FIG. 5B in which the ratio of the liquid component is medium, the refrigerant is heated by the heater 72, so that the dryness of the refrigerant is reduced at the position Pb closer to the position P2 than in the case of FIG. 5A. It becomes 1. In the region closer to the position P2 than the position Pb, the temperature of the refrigerant rises due to the heating by the heater 72. Therefore, the amount of temperature rise at the position P2 is ΔTb, which is smaller than ΔTa in the case of FIG. 5A.

In the case of FIG. 5 (C) where the ratio of the liquid component is the largest, the dryness of the refrigerant is increased at the position Pc closer to the position P2 than in the case of FIG. 5 (B) by heating the refrigerant by the heater 72. It becomes 1. In the region closer to the position P2 than the position Pc, the temperature of the refrigerant rises due to the heating by the heater 72. As a result, the amount of temperature rise at the position P2 is ΔTc, which is even smaller than ΔTb in the case of FIG. 5B.

As described above, it is possible to determine whether or not the filling amount of the refrigerant in the refrigerant circuit RC is appropriate based on the temperature rise amount of the refrigerant when the refrigerant is heated by the heater 72 in the refrigerant amount detecting unit 70. Further, based on the magnitude of the temperature rise amount, it is possible to know to what extent the refrigerant filled in the refrigerant circuit at the present time is filled with respect to the appropriate filling amount.

The above determination method can also be applied to a refrigerating apparatus that is not provided with a liquid receiver and a supercooling heat exchanger. This case is also the same as in FIG. 1 in that one end of the pipes (86 and 87) constituting the bypass circuit BC is connected to the outlet side of the condenser 20. The bypass circuit BC returns a part of the refrigerant that has passed through the condenser 20 to the compressor 10 without passing through the load-side unit 3.

[Procedure for filling the refrigerant circuit with refrigerant]
FIG. 6 is a flowchart showing a procedure for filling the refrigerant circuit with the refrigerant in the refrigerating apparatus of FIG. Here, the refrigerant filling procedure proceeds in the order of initial filling, additional filling, and final filling. Here, the additional filling is continuously performed, and it is characterized in that the filling speed is lowered when the refrigerant filling amount approaches an appropriate value based on the above temperature rise amount. The final filling is performed in order to prevent the refrigerant filling amount from being varied due to changes in the outside air condition due to the season or the like. Hereinafter, a procedure for controlling the amount of the refrigerant charged at the time of filling the refrigerant will be described with reference to FIGS. 1 and 6.

First, in step S100, the control device 100 receives an input from the user for starting control of the filling amount of the refrigerant via the input device 122 of FIG.

In the next step S110, the control device 100 receives an input of the specifications of the component having a large influence on the amount of the refrigerant from the user via the input device 122. The specifications of the specifically required components are as follows.

(I) The diameter and length of the gas extension pipe 900 for connecting the heat source side unit 2 and the load side unit 3. The gas extension pipe corresponds to the pipe 85 in FIG.

(Ii) The diameter and length of the liquid extension pipe 910 for connecting the heat source side unit 2 and the load side unit 3. The liquid extension pipe corresponds to the pipe 83 in FIG.

(Iii) Internal volume of the condenser 20.
(Iv) Internal volume of the evaporator 60.

(V) Internal volume of the receiver 30.
(Vi) A pressure value (also referred to as a constant pressure cut off value) for stopping the compressor 10 due to a decrease in the suction pressure of the compressor 10. Instead of this, the target evaporation temperature may be used.

The above specification information is particularly needed to determine the filling amount in the initial and final filling of the refrigerant. Since the internal volumes of the other pipes are smaller than the internal volumes of the gas extension pipe 900 and the liquid extension pipe 910, they can be ignored.

In the next step S120, the control device 100 instructs the refrigerant circuit RC to be filled with the initial filling amount of the refrigerant. The initial filling amount is the minimum amount of refrigerant required to operate the compressor 10. For example, the control device 100 may display the initial filling amount on the display as the output device 120 of FIG. 2, or may notify the initial filling amount by voice output. When a mechanism capable of automatically filling a desired filling amount of the refrigerant is provided, the control device 100 instructs the refrigerant circuit RC to automatically fill the refrigerant circuit RC with the initial filling amount of the refrigerant.

In the next step S130, the control device 100 causes the compressor 10 to start operation. The rotation frequency of the compressor 10 is fixed to a relatively small value, for example 50 Hz or 60 Hz, in order to suppress the pressure loss. However, as long as it is in the frequency range where the influence of pressure loss is small, it is not always necessary to fix it to the above value.

At the beginning of the operation of the compressor 10, the suction pressure LP is smaller than the threshold value (also referred to as a constant pressure cut), so that the compressor 10 may stop (YES in step S140). In this case, the control device 100 returns the process to step S130 and restarts the operation of the compressor 10.

When the compressor 10 is in the continuous operation state (NO in step S140), in the next step S150, the control device 100 turns on (ON) the heater 72 provided in the refrigerant amount detection unit 70.

If the compressor 10 is stopped within a certain period of time (for example, within 2 minutes) after the heater 72 is turned on (NO in step S170, YES in step S160), the control device 100 advances the process to step S260.

In step S260, the control device 100 turns off the heater 72 provided in the refrigerant amount detecting unit 70. Further, in the next step S270, the control device 100 increases the variable N for counting the number of abnormal stops of the compressor 10 by one. The initial value of the variable N is 0. When the variable N representing the number of abnormal stops of the compressor 10 has not reached the upper limit value (for example, 4) (NO in step S280), the control device 100 returns the process to step S130 and operates the compressor 10. To start again.

When the variable N representing the number of abnormal stops of the compressor 10 reaches the upper limit value (for example, 4) (YES in step S280), the control device 100 advances the process to step S290. In step S290, the control device 100 notifies the user of the error by the output device 120 of FIG. Further, the control device 100 instructs to suppress the frequency of starting and stopping the compressor. For example, the control device 100 instructs the compressor 10 to change the rotation frequency.

When a certain period of time has elapsed without stopping the compressor 10 after turning on the heater 72 (YES in step S170, NO in steps S160 and S180), the control device 100 advances the process to step S190.

In step S190, the control device 100 acquires the data of each part. Specifically, the control device 100 acquires the detection values of the temperatures T1 and T2 from the temperature sensors 73 and 74 of the refrigerant amount detection unit 70, respectively. Further, the control device 100 acquires the condensation temperature CT, the outlet temperature OT of the supercooling heat exchanger 40, the outside air temperature AT, and the evaporation temperature ET by the temperature sensor. Further, the control device 100 uses the pressure sensors 90 and 92 to determine the refrigerant pressure on the suction side of the compressor 10 (that is, the low pressure side pressure LP) and the refrigerant pressure on the discharge side of the compressor 10 (that is, the high pressure side pressure HP). To detect.

In the next step S200, the control device 100 determines whether or not the difference between the acquired temperature T2 and the temperature T1 (T2-T1), that is, the amount of temperature rise of the refrigerant by the heater 72 is smaller than the threshold value Tth1. do. However, since the acquired temperatures T1 and T2 vary, this determination is made using the average value of a plurality of consecutive data (for example, acquired data for 3 minutes) up to the present time. Further, the control device 100 determines whether or not T2-T1 <Tth1 is satisfied continuously for a certain period of time (for example, 15 minutes).

The threshold value Tth1 is set to, for example, about 4 to 5 ° C. in consideration of the error of the temperature sensor. The fact that T2-T1 is smaller than the threshold value Tth1 means that the temperature T1 and the temperature T2 are substantially equal to each other.

FIG. 7 is a timing diagram for explaining an example of averaging temperature data. With reference to FIG. 7, the timing of data sampling is shown on the time axis. Data sampling is performed every 20 seconds.

As shown in FIG. 7, the control device 100 averages nine data acquired in the last three minutes up to the present time every minute. Therefore, when 3 minutes have passed since the heater 72 was turned on, the control device 100 calculates the average value Ave1 of the nine data from the lapse of 20 seconds to the lapse of 180 seconds. When 4 minutes have passed since the heater 72 was turned on, the control device 100 calculates the average value Ave2 of the nine data from the lapse of 80 seconds to the lapse of 240 seconds. When 5 minutes have passed since the heater 72 was turned on, the control device 100 calculates the average value Ave3 of the nine data from the lapse of 140 seconds to the lapse of 300 seconds.

The same applies after that. Therefore, as shown in FIG. 7, when 14 minutes have passed since the heater 72 was turned on, the control device 100 calculates the average value Ave14 of the nine data from the lapse of 680 seconds to the lapse of 840 seconds. .. When 15 minutes have passed since the heater 72 was turned on, the control device 100 calculates the average value Ave15 of the nine data from the lapse of 740 seconds to the lapse of 900 seconds.

The control device 100 determines whether or not all the temperature rise amounts (T2-T1) calculated using each of the above 15 average values Ave1 to Ave15 are smaller than the threshold value Tth1. If the calculated 15 temperature rises are all smaller than the threshold value Tth1, it means that the determination condition is satisfied continuously for a certain period of time. If the temperature rise amount (T2-T1) calculated using each of the average values Ave1 and Ave2 is equal to or higher than the threshold value Tth1, it is necessary to calculate the average value at least after 16 minutes and 17 minutes, respectively. There is.

The above calculation of averaging is the same as performing a moving average with a window width of 3 minutes and outputting the moving average value every 1 minute. When the temperature rise amount calculated using the output moving average value becomes less than the threshold value Tth1 15 times in a row, it is determined that the refrigerant circuit is sufficiently filled with the refrigerant.

Returning to FIG. 6, a procedure after the determination process in step S200 will be described. Hereinafter, the case where the above determination conditions (that is, T2-T1 <Tth1) are not continuously satisfied for a certain period of time (YES in step S200) and the case where the above determination conditions (that is, NO in step S200) are satisfied will be described separately. do. For example, 15 minutes is set as a fixed time, but the time is not limited to this.

(1. NO in step S200)
When the above determination condition is not continuously satisfied for a certain period of time (NO in step S200), the control device 100 determines that the amount of the refrigerant charged is insufficient. In this case, the control device 100 instructs the next step S210 to start or continue the additional filling of the refrigerant to the refrigerant circuit RC. Once the additional filling is started, the refrigerant filling is continuously performed.

For example, the control device 100 may display the display as the output device 120 of FIG. 2 to start or continue the addition of the refrigerant, or may notify the effect by voice output. If a mechanism capable of automatically filling the refrigerant at a desired filling rate is provided, the controller 100 may instruct the mechanism to automatically disclose or continue the refrigerant filling.

Further, in step S210, the control device 100 is instructed to change the filling speed of the refrigerant according to the temperature rise amount (T2-T1) of the refrigerant. Specifically, as shown in FIG. 8, when the temperature rise of the refrigerant is relatively large, the filling speed of the refrigerant is set higher than when the temperature rise of the refrigerant is relatively small.

FIG. 8 is a flowchart showing the procedure of step S210 of FIG. 6 in more detail. With reference to FIG. 8, a threshold value Tth2 larger than the threshold value Tth1 is preset. The threshold value Tth2 is set to, for example, a temperature rise amount (T2-T1) at a filling amount slightly smaller than the appropriate filling amount as shown in FIG. 5 (C).

In step S400, the control device 100 determines whether or not the temperature rise amount (T2-T1) of the refrigerant in the refrigerant amount detecting unit 70 is equal to or higher than the threshold value Tth2. When the amount of temperature rise is equal to or higher than the threshold value Tth2 (YES in step S400), the control device 100 instructs the next step S410 to start or continue filling the refrigerant at a high flow rate. As a result, the refrigerant can be continuously filled in the refrigerant circuit at a high flow rate up to a certain amount, so that the total time required for the refrigerant filling work can be shortened.

On the other hand, when the temperature rise amount is equal to or more than the threshold value Tth1 but less than the threshold value Tth2 (YES in step S400), the control device 100 proceeds to step S420. In step S420, the control device 100 instructs the refrigerant filling speed to be slower than in step S410. This makes it possible to prevent the refrigerant circuit RC from being overfilled with the refrigerant.

As an example, the filling speed of the refrigerant in step S410 is about 3% of the maximum amount of the filled refrigerant per minute. The filling speed of the refrigerant in step S430 is about 1% of the maximum amount of the filled refrigerant per minute.

The refrigerant filling speed may be switched to three or more stages. For example, a threshold value Tth3 larger than the above threshold value Tth2 may be further set. In this case, if the temperature rise amount (T2-T1) in the refrigerant amount detecting unit 70 is the threshold value Tth3 or more, the control device 100 fills the refrigerant circuit with the refrigerant at a speed higher than the filling speed in the above step S410. ..

Returning to FIG. 6, if the compressor 10 does not stop (NO in step S180), the control device 100 repeatedly executes the above steps S190, S200, and S210 until YES in step S200.

On the other hand, if the compressor 10 is stopped during the execution of this repetition (YES in step S180), the control device 100 temporarily stops the additional filling of the refrigerant (step S250). After that, the control device 100 executes the above-mentioned steps S260 to S280.

Specifically, in step S260, the control device 100 turns off the heater 72 provided in the refrigerant amount detecting unit 70. In the next step S270, the control device 100 increases the variable N for counting the number of abnormal stops of the compressor 10 by one.

In step S280, when the number of abnormal stops N of the compressor 10 has not reached the upper limit value (NO in step S280), the control device 100 returns to step S130 and restarts the operation of the compressor 10. When the number of abnormal stops N of the compressor 10 reaches the upper limit value (YES in step S280), the control device 100 advances the process to step S290. In step S290, the control device 100 notifies the user of the error by the output device 120 of FIG. Further, the control device 100 instructs to suppress the frequency of starting and stopping the compressor. For example, the control device 100 instructs the compressor 10 to change the rotation frequency or limit the refrigerant filling speed.

(2. YES in step S200)
When the above determination conditions are continuously satisfied for a certain period of time (YES in step S200), the control device 100 determines that the filling amount of the refrigerant is substantially appropriate. In this case, the control device 100 stops filling the refrigerant circuit RC with the refrigerant in the next step S220. In the next step S230, the control device 100 turns off the heater 72 in the refrigerant amount detecting unit 70.

Further, in the next step S240, the control device 100 calculates the refrigerant shortage according to the change of the outside air condition such as the season so that the refrigerant shortage does not occur throughout the year. This refrigerant deficiency means the amount of deficient refrigerant to be additionally filled in the refrigerant circuit RC in the end. The method of calculating the amount of insufficient refrigerant will be described later.

The control device 100 instructs the refrigerant circuit RC to be filled with the calculated insufficient amount of refrigerant. For example, the control device 100 may display the insufficient refrigerant amount on the display as the output device 120 of FIG. 2, or may notify the insufficient refrigerant amount by voice output. If a mechanism capable of automatically filling a desired amount of refrigerant is provided, the control device 100 instructs the mechanism to automatically fill the refrigerant circuit RC with the insufficient amount of refrigerant. May be good.

This completes the procedure for controlling the amount of refrigerant charged. In step S240, when the total amount of the already filled refrigerant is sufficient (that is, when the calculated insufficient refrigerant amount is almost 0), it is not necessary to execute the final filling of the refrigerant.

[Calculation method of insufficient refrigerant amount]
The amount of insufficient refrigerant is the internal volume of each of the condenser 20, the liquid extension pipe 910, the gas extension pipe 900, the evaporator 60, and the liquid receiver 30, as well as the maximum density of the refrigerant expected in one year and the time when the refrigerant is filled. It is calculated based on the difference from the refrigerant density of. By filling the refrigerant circuit RC with the calculated insufficient refrigerant amount, it is possible to prevent the refrigerant filling amount from being varied due to changes in the outside air condition due to the season or the like.

The shortage refrigerant amount ΔMr is expressed as the sum of the shortage refrigerant amounts of each of the five elements in the configuration of the refrigerating apparatus 1 in which the fluctuation of the refrigerant amount is large. That is,
ΔMr = ΔMr _cond + ΔMr _PL + ΔMr _PG + ΔMr _eva + ΔMr _rec … (1)
The amount of insufficient refrigerant ΔMr can be calculated by Here, ΔMr _cond is the amount of insufficient refrigerant in the condenser 20. ΔMr _PL is the amount of insufficient refrigerant in the liquid extension pipe 910. ΔMr _PG is the amount of insufficient refrigerant in the gas extension pipe 900. ΔMr _eva is the amount of insufficient refrigerant in the evaporator 60. ΔMr _rec is the amount of insufficient refrigerant in the receiver 30. Hereinafter, the method of calculating the amount of each insufficient refrigerant will be described in detail.

(1. Insufficient amount of refrigerant in the condenser 20 ΔMr _cond )
The control device 100 uses the relationship between the refrigerant density ρ _cond in the condenser 20 and the condensation temperature (CT), which is set in advance, from the detected condenser outlet temperature (condensation temperature CT at the time of filling) to the time of filling. The refrigerant density in the condenser 20 of the above is calculated. The control device 100 obtains the difference value between the preset reference density and the calculated refrigerant density in the condenser 20 at the time of filling as the density fluctuation Δρ _cond . The reference density is the maximum value of the refrigerant density in the condenser 20 which varies depending on the temperature. The control device 100 obtains the insufficient refrigerant amount ΔMr _cond of the condenser 20 by multiplying the calculated density fluctuation Δρ _cond by the internal volume V _cond of the condenser 20.

For example, if the condensation temperature at the maximum refrigerant density is 53 ° C., the density fluctuation Δρ _cond will be.
Δρ _cond = 1.7 × (53-CT)… (2)
Represented by. In the above equation (2), CT represents the condensation temperature at the time of filling, and 1.7 is an experimentally obtained coefficient. The above condensation temperature and coefficient are examples, and differ depending on the type of refrigerant, operating conditions, and the like.

(2. Insufficient amount of refrigerant in the liquid extension pipe 910 ΔMr _PL )
The control device 100 is filled from the detected outlet temperature OT of the overcooling heat exchanger by using the relationship between the refrigerant density ρ _PL in the liquid extension pipe 910 and the refrigerant temperature in the liquid extension pipe 910, which is set in advance. The refrigerant density in the liquid extension pipe 910 at the time is calculated. The control device 100 obtains the difference value between the preset reference density and the calculated refrigerant density in the liquid extension pipe 910 at the time of filling as the density fluctuation Δρ _PL . The reference density is the maximum value of the refrigerant density in the liquid extension pipe 910 which fluctuates depending on the temperature. The control device 100 obtains the insufficient amount of refrigerant ΔMr _PL in the liquid extension pipe 910 by multiplying the calculated density fluctuation Δρ _PL by the internal volume V _PL of the liquid extension pipe 910.

For example, if the liquid pipe temperature at the maximum refrigerant density is 17 ° C, the density fluctuation Δρ _PL is
Δρ _PL = -5 × (17-OT)… (3)
Represented by. In the above equation (3), OT represents the outlet temperature of the supercooling heat exchanger 40 at the time of filling, and -5 is an experimentally obtained coefficient. The above liquid pipe temperature and coefficient are examples, and differ depending on the type of refrigerant, operating conditions, and the like.

(3. Insufficient amount of refrigerant in gas extension pipe 900 ΔMr _PG )
The control device 100 uses the relationship between the refrigerant density ρ _PG in the gas extension pipe 900 and the evaporation temperature ET, which is set in advance, from the detected evaporation temperature ET at the time of filling to the gas extension pipe 900 at the time of filling. Calculate the refrigerant density. The control device 100 obtains the difference value between the preset reference density and the calculated refrigerant density in the gas extension pipe 900 at the time of filling as the density fluctuation Δρ _PG . The reference density is the maximum value of the refrigerant density in the gas extension pipe 900 which fluctuates depending on the temperature. The control device 100 obtains the insufficient amount of refrigerant ΔMr _PG in the gas extension pipe 900 by multiplying the calculated density fluctuation Δρ _PG by the internal volume V _PG of the gas extension pipe 900.

More specifically, the refrigerant density of the gas extension pipe 900 changes depending on the evaporation temperature ET. The width ΔET at which the evaporation temperature ET fluctuates is set to, for example, 5 ° C. Assuming that the target evaporation temperature (ETm) actually used and the evaporation temperature ET at the time of filling are different, the density fluctuation Δρ _PG of the gas extension pipe 900 is
Δρ _PG = 0.8 × (ΔET (= 5) + (ETm-ET))… (4)
Represented by. In the above equation (4), 0.8 is an experimentally obtained coefficient. The fluctuation range and coefficient of the above evaporation temperature are examples, and differ depending on the type of refrigerant, operating conditions, and the like.

(4. Insufficient amount of refrigerant in the evaporator 60 ΔMr _eva )
The control device 100 uses a preset relationship between the refrigerant density ρ _eva in the evaporator 60, the evaporation temperature ET, and the inlet temperature of the evaporator 60 to calculate the refrigerant density in the evaporator 60 at the time of filling. .. The control device 100 further uses the evaporation temperature ET at the time of filling, the filling, and the outlet temperature OT of the supercooling heat exchanger 40 to calculate the refrigerant density in the evaporator 60 at the time of filling. The control device 100 obtains the difference value between the preset reference density and the refrigerant density at the time of filling as the density variation Δρ _eva . The control device 100 obtains the insufficient amount of refrigerant ΔMr _eva in the evaporator 60 by multiplying the calculated density fluctuation Δρ _eva by the internal volume V _eva of the evaporator 60.

More specifically, the refrigerant density ρ _eva of the evaporator 60 changes depending on the evaporation temperature ET and the inlet temperature of the evaporator 60. The width ΔET at which the evaporation temperature ET fluctuates is set to, for example, 5 ° C. Assuming that the target evaporation temperature (ETm) actually used and the evaporation temperature ET at the time of filling are different, the density fluctuation Δρ _eva of the evaporator 60 is
Δρ _eva = 3 × (ΔET (= 5) ＋ (ETm－ET)) ＋ (OT-17) × 29/28… (5)
Represented by. In (5) above, 3 and 29/28 are experimentally obtained coefficients. The fluctuation range of the evaporation temperature, the liquid pipe temperature (17 ° C.) at which the refrigerant density is maximized, and the coefficient are examples, and differ depending on the type of refrigerant, operating conditions, and the like.

(5. Insufficient amount of refrigerant in the receiver 30 ΔMr _rec )
The control device 100 fills from the detected condenser outlet temperature (condensation temperature CT at the time of filling) by using the relationship between the refrigerant density ρ _rec in the liquid receiver 30 and the condensation temperature (CT) set in advance. The refrigerant density in the receiver 30 at the time is calculated. The control device 100 obtains the difference value between the preset reference density and the calculated refrigerant density in the liquid receiver 30 at the time of filling as the density fluctuation Δρ _rec . The reference density is the maximum value of the refrigerant density in the receiver 30 that varies depending on the temperature. The control device 100 obtains the insufficient amount of refrigerant ΔMr _rec of the receiver 30 by multiplying the calculated density fluctuation Δρ _rec by the internal volume V _rec of the receiver 30.

For example, if the condensation temperature at the maximum refrigerant density is 60 ° C, the density fluctuation Δρ _rec is
Δρ _rec = 3.3 × (60-CT)… (6)
Represented by. In the above equation (6), CT represents the condensation temperature at the time of filling, and 3.3 is an experimentally obtained coefficient. The above condensation temperature and coefficient are examples, and differ depending on the type of refrigerant, operating conditions, and the like.

[Placement position of refrigerant amount detector]
As described above, in the heat source side unit 2 of the present embodiment, the appropriateness of the filling amount of the refrigerant is determined based on the temperature rise amount of the refrigerant by the heater 72 in the refrigerant amount detecting unit 70. Therefore, the accuracy of determining the amount of the refrigerant depends on the accuracy of detecting the amount of temperature rise of the refrigerant by the heater 72.

Therefore, the refrigerant amount detecting unit 70 is arranged at a position that is not easily affected by the wind that disturbs the detection of the temperature rise amount. Specifically, it is preferable that the refrigerant amount detecting unit 70 is arranged at a position where the influence of the air flow is small as compared with the condenser 20. The wind to be affected is included, the wind that has passed through the condenser 20, the wind before passing through the condenser 20, and the natural wind. As a result, it is possible to prevent the refrigerant amount detecting unit 70 from being affected by the wind and causing an error in the temperature rise amount.

FIG. 9 is a diagram schematically showing the structure of the heat source side unit 2 of the refrigerating apparatus 1. With reference to FIG. 9, the inside of the heat source side unit 2 is divided into a heat exchange chamber 202 and a machine room 204 by a partition plate 206. The heat exchange chamber 202 houses a condenser 20, a liquid receiver 30, a supercooled heat exchanger 40 (none of which is shown), and fans 22 and 42. The condenser 20 and the supercooled heat exchanger 40 (hereinafter, may be collectively referred to as “heat exchange section”) and the fans 22 and 42 are provided on the side surface of the housing of the heat source side unit 2. In the example, the heat exchange section is provided on the back side and the fans 22 and 42 are provided on the front side, and the exhaust heat air of the heat exchange section flows from the back side to the front side of the heat exchange chamber 202. The machine room 204 houses the compressor 10, each pipe, the pressure sensors 90 and 92, and the control device 100.

Then, in the heat source side unit 2 according to the first embodiment, the refrigerant amount detecting unit 70 is housed in the machine room 204. A wind accompanying the operation of the fans 22 and 42 or a natural wind is flowing in the heat exchange chamber 202 while the fan is stopped, and the refrigerant amount detection unit is in the heat exchange chamber 202 in which such wind flows. When the 70 is arranged, the refrigerant amount detecting unit 70 (particularly, the temperature sensors 73 and 74) is affected by the wind, which may cause an error in the measurement of the temperature rise amount of the refrigerant by the heater 72. In this example, since the refrigerant amount detecting unit 70 is housed in the machine room 204 separated from the heat exchange room 202 by the partition plate 206, it is not affected by the wind. Therefore, according to the heat source side unit 2, the amount of temperature rise of the refrigerant by the heater 72 can be accurately measured.

In the above, the liquid receiver 30 is arranged in the heat exchange chamber 202, but may be arranged in the machine room 204. Other positions may be used as long as the influence of the air flow is small.

[Effect of Embodiment 1]
Hereinafter, the effect of the first embodiment will be described in comparison with other methods for determining the suitability of the refrigerant filling amount.

FIG. 10 is a diagram for explaining a method for determining the suitability of other refrigerant filling amounts. Specifically, FIG. 10A shows the relationship between the degree of supercooling at the outlet of the supercooling heat exchanger 40 and the total filling amount of the refrigerant filled in the refrigerant circuit RC. FIG. 10B shows the relationship between the temperature efficiency ε and the total amount of the refrigerant filled in the refrigerant circuit RC. The temperature efficiency ε will be described later.

In FIGS. 10A and 10B, the filling amount when an appropriate amount of the refrigerant is filled is defined as E. The refrigerant filling amount E substantially corresponds to the refrigerant filling amount when the temperature rise amount (T2-T1) in the refrigerant amount detecting unit 70 becomes less than the threshold value Tth1.

(Method 1)
The appropriateness of the amount of the filled refrigerant can be determined by the degree of supercooling at the outlet of the supercooling heat exchanger 40. Here, the degree of supercooling is obtained by subtracting the outlet temperature OT of the supercooling heat exchanger 40 from the condensation temperature CT. When the degree of supercooling exceeds the threshold value Sth, it is determined that the refrigerant circuit RC is filled with an appropriate amount of refrigerant.

As shown in FIG. 10A, this determination method is greatly affected by the operating conditions of the refrigerating apparatus 1. In the case of the operating condition A, it is determined to be appropriate when the amount of the refrigerant is R1, whereas in the case of the operating condition B, it is determined to be appropriate when the amount of the refrigerant is R2. The reason for this is that the degree of supercooling varies greatly depending on the operating conditions of the refrigerating device 1. Therefore, in order to be able to determine under any operating conditions, the threshold value Sth of the degree of supercooling must be set to be considerably small. As a result, the refrigerant filling amounts R1 and R2 when the degree of supercooling of the refrigerant exceeds the threshold Sth are considerably smaller than the refrigerant filling amount E when the temperature rise amount in the refrigerant amount detecting unit 70 becomes less than the threshold Tth1. ..

(Method 2)
As another method, the refrigerant shortage can be determined by using the temperature efficiency ε, which is the value obtained by dividing the degree of supercooling of the refrigerant at the outlet of the supercooling heat exchanger 40 by the maximum temperature difference of the supercooling heat exchanger. When the supercooling heat exchanger 40 is cooled by the outside air, the temperature efficiency ε is determined by using the condensation temperature CT, the outlet temperature OT of the supercooling heat exchanger 40, and the outside air temperature AT.
ε = (CT-OT) / (CT-AT)… (7)
It is represented by. When the temperature efficiency ε exceeds the threshold value εth, it is determined that the refrigerant circuit RC is filled with an appropriate amount of refrigerant.

As shown in FIG. 10B, in the case of this method, the influence of the operating conditions A and B is small. However, although the temperature efficiency ε changes slightly depending on the operating conditions of the refrigerating apparatus, it is necessary to set the threshold value εth in consideration of the difference in the temperature efficiency ε. As a result, the refrigerant filling amount R3 when the temperature efficiency ε reaches the threshold value εth is slightly smaller than the refrigerant filling amount E when the temperature rise amount in the refrigerant amount detecting unit 70 reaches the threshold value Tth1. Further, the method 2 has the following serious problems.

First, the temperature efficiency ε may not be determined because the error becomes large depending on the operating conditions. First, when the supercooling heat exchanger 40 is air-cooled, as shown in the above equation (7), the maximum temperature difference of the supercooling heat exchanger 40 is obtained by the condensation temperature CT-outside air temperature AT. Here, when the heat exchange performance of the condenser 20 is lowered due to the decrease in the air volume of the fan 22 of the condenser 20, the difference between the condensation temperature CT and the outside air temperature AT is too large, which causes a problem. In such a case, the temperature efficiency may decrease even when a sufficient amount of refrigerant is sealed in the refrigerant circuit, and as a result, overfilling may occur, so it is not possible to determine whether or not the refrigerant is insufficient. ..

Further, when the condensation load is small because the evaporation temperature is low and the operating frequency of the compressor 10 is low, the difference between the condensation temperature CT and the outside air temperature AT is too small, which causes a problem. In such a case, the temperature efficiency calculated due to the error of the temperature sensor may deviate significantly from the true value, so that it is not possible to determine whether or not the refrigerant is insufficient.

On the other hand, when the overcooling heat exchanger 40 is a double tube or plate heat exchange system, the maximum temperature difference of the overcooling heat exchanger 40 is the difference between the condensation temperature CT and the intermediate pressure side saturation temperature of the overcooling heat exchanger 40. Demanded by. Here, it becomes a problem when the difference between the condensation temperature CT and the saturation temperature on the intermediate pressure side of the supercooling heat exchanger 40 is too small. In this case, the temperature efficiency calculated due to the error of the temperature sensor may deviate significantly from the true value, so that it is not possible to determine whether or not the refrigerant is insufficient.

Secondly, in the case of a non-cobo-boiling mixed refrigerant, there is a difference (that is, a temperature gradient) between the refrigerant temperature of the saturated liquid and the refrigerant temperature of the saturated gas even at the same pressure, which is a problem. For example, in the case of an azeotropic refrigerant, as shown in FIG. 10 (A) of (Method 1), the degree of supercooling (that is, CT-OT) becomes zero when the refrigerant becomes insufficient. On the other hand, in the case of a non-azeotropic refrigerant, the degree of supercooling (that is, CT-OT) does not become zero due to the temperature gradient even when the refrigerant becomes insufficient. As a result, the determination accuracy is lowered, and the determination becomes difficult unless the threshold value εth of the temperature efficiency ε is set large.

In the determination of the refrigerant filling amount using the refrigerant amount detecting unit 70 of the first embodiment, any of the above problems can be improved by adjusting the heating amount of the heater 72. That is, the variation in the determination result depending on the operating conditions can be reduced, and there is almost no operating state in which the determination becomes difficult. It is not necessary to determine that the amount of refrigerant smaller than the appropriate amount of refrigerant E is appropriate as in the above methods 1 and 2, and an accurate determination result can be obtained. Further, as described with reference to FIG. 4B, an appropriate filling amount can be accurately determined even in the case of a non-azeotropic mixed refrigerant.

Further, in the case of the first embodiment, the refrigerant circuit RC is continuously filled with the refrigerant, and the filling speed of the refrigerant is controlled to be slowed down at a stage slightly before the substantially appropriate filling amount. To. As a result, it is possible to prevent the refrigerant circuit RC from being overfilled with the refrigerant and to shorten the time required for the filling operation.

Further, in the first embodiment, the refrigerant circuit is finally filled with the refrigerant of the insufficient amount of the refrigerant calculated according to the equation (1), so that the refrigerant circuit is provided with an appropriate amount of the refrigerant so as not to be short of the refrigerant throughout the year. Can be enclosed.

Embodiment 2.
When the refrigerant flows through the bypass circuit BC provided with the refrigerant amount detecting unit, the amount of the refrigerant flowing through the evaporator 60 of the load side unit 3 decreases. Therefore, if the refrigerant continues to flow through the bypass circuit BC, the performance of the refrigerating apparatus may be affected.

Therefore, in the second embodiment, the on-off valve is provided in the bypass circuit BC. The on-off valve is opened during the refrigerant filling operation. During the subsequent normal operation, the on-off valve is closed.

FIG. 11 is an overall configuration diagram of a refrigerating apparatus using the heat source side unit according to the second embodiment. With reference to FIG. 11, the refrigerating apparatus 1A includes a heat source side unit 2A and a load side unit 3. The heat source side unit 2A includes the refrigerant amount detection unit 70A in place of the refrigerant amount detection unit 70 in the heat source side unit 2 of the first embodiment shown in FIG.

The refrigerant amount detecting unit 70A further includes a solenoid valve 79 in the refrigerant amount detecting unit 70 of the first embodiment shown in FIG. 1. The solenoid valve 79 is provided in the pipe 86 upstream of the capillary tube 71, and opens and closes according to an instruction from the control device 100. Although the solenoid valve 79 can be provided in the pipe 87 downstream of the capillary tube 71, it is preferable to provide the solenoid valve 79 in the pipe 86 upstream of the capillary tube 71. When the solenoid valve 79 is opened, the refrigerant flows through the capillary tube 71 and the pipe 87, and it becomes possible to determine whether or not the amount of the refrigerant is appropriate. When the solenoid valve 79 is in the closed state, the flow of the refrigerant to the capillary tube 71 and the pipe 87 is cut off, so that the determination of the appropriateness of the amount of the refrigerant cannot be executed.

Since the other points of FIG. 11 are the same as those of FIG. 1, the same or corresponding parts are designated by the same or similar reference numerals, and the description thereof will not be repeated.

FIG. 12 is a diagram showing an operation pattern of the solenoid valve 79 and the heater 72. With reference to FIG. 12, the solenoid valve 79 is turned on (opened) and the heater 72 is also turned on during the control of the refrigerant filling amount. In the normal state, that is, when the control of the refrigerant filling amount is not executed, the solenoid valve 79 is turned off (closed) and the heater 72 is also turned off.

Further, when the solenoid valve 79 is off, it is possible to determine the failure of the heater. With reference to FIG. 12, the solenoid valve 79 is turned off (closed) and the heater 72 is turned on during the determination of the heater failure. A specific method for detecting a heater failure will be described later with reference to FIG.

In FIG. 11, the solenoid valve 79 is provided in the pipe 86, but the solenoid valve 79 may be provided in the pipe 87 downstream of the capillary tube 71. However, it is preferable to provide the solenoid valve 79 in the pipe 86 because the amount of the liquid refrigerant that normally falls asleep in the bypass circuit BC can be reduced by disposing the solenoid valve 79 on the upstream side in the bypass circuit BC. Further, it is more preferable that the solenoid valve 79 is provided at a position as close as possible to the branch portion where the pipe 86 is branched from the pipe 82.

FIG. 13 is a flowchart showing a procedure for filling the refrigerant circuit RC with the refrigerant in the refrigerating apparatus of FIG.

The flowchart of FIG. 13 is a modification of the flowchart of FIG. In the flowchart of FIG. 13, step S154 for opening the solenoid valve 79 is added. This step S154 is executed after step S150 for turning on the heater 72 and before step S160 for confirming whether the compressor 10 is stopped. Further, in the flowchart of FIG. 13, the step S225 for closing the solenoid valve 79 is executed after the steps S230 and S260 for turning off the heater 72, respectively.

Further, in the flowchart of FIG. 13, step S152 for determining the failure of the heater 72 is executed. This step S152 is executed after step S150 for turning on the heater 72 and before step S154 for opening the solenoid valve 79. That is, the failure determination of the heater is executed in a state where the refrigerant is not flowing through the bypass circuit BC. Even if the heater 72 is turned on in this state, if the temperatures T1 and T2 detected by the temperature sensors 73 and 74 hardly rise, it is determined that the heater 72 has failed. This makes it possible to prevent an erroneous determination that the refrigerant shortage has not occurred even though the refrigerant shortage has actually occurred. A specific flowchart of step S152 for determining the failure of the heater 72 will be described later with reference to FIG.

Further, in the flowchart of FIG. 13, step S192 for determining the failure of the solenoid valve 79 is added. The step S192 for determining the failure of the solenoid valve is executed after the step S190 for acquiring the data and before the step S200 for determining whether or not the temperature increase amount (T2-T1) is less than the threshold value Tth1.

By providing the electromagnetic valve 79, the refrigerant can flow to the bypass circuit BC only during the control of the refrigerant filling amount. However, when the solenoid valve 79 is closed and malfunctions, the flow of the refrigerant does not occur in the bypass circuit BC. In this case, since the difference between the temperature T2 and the temperature T1 (T2-T1) becomes small, there is a possibility that it is erroneously determined that the refrigerant shortage does not occur even though the refrigerant shortage actually occurs. .. Therefore, even if the difference between the temperature T2 and the temperature T1 (T2-T1) is small, if any of the temperatures T1 and T2 is equal to or higher than the threshold value, it is determined that the solenoid valve 79 is closed and failed. A specific flowchart of step S192 for determining the failure of the solenoid valve 79 will be described later with reference to FIG.

Since the other points of FIG. 13 are the same as those of FIG. 6, the description will not be repeated by assigning the same or similar reference numerals to the same or corresponding steps.

FIG. 14 is a flowchart showing a procedure for determining a heater failure in the refrigerant amount detection unit.

At the time of starting the procedure shown in FIG. 14, the control device 100 controls the heater 72 provided in the refrigerant amount detecting unit 70 to be turned on (step S150 in FIG. 13).

In step S500, the control device 100 acquires the detection values of the temperatures T1 and T2 from the temperature sensors 73 and 74 of the refrigerant amount detection unit 70A, respectively. The detection of the temperatures T1 and T2 is executed after a predetermined time has elapsed from turning on the heater 72.

In the next step S510, the control device 100 determines whether or not the acquired temperature T1 or T2 is higher than the threshold value Tth2. The threshold value Tth2 is a value for determining whether or not the heater 72 is operating. For example, the threshold value Tth1 in step S200 of FIGS. 6 and 13 is set to a small value of about 4 to 5 ° C., whereas the threshold value Tth4 is set to a value of about 10 to 20 ° C.

As a result, when at least one of the acquired temperatures T1 and T2 is lower than the threshold value Tth2 (YES in step S510), the control device 100 advances the process to step S520. In step S520, the control device 100 notifies the user via the output device 120 that the heater 72 has failed. This makes it possible to prevent erroneous determination that the filling amount of the refrigerant is appropriate due to a failure of the heater 72, even though the filling amount is actually insufficient.

FIG. 15 is a flowchart showing a procedure for determining a failure of the solenoid valve. With reference to FIG. 15, in step S600, the control device 100 confirms whether the heater 72 is in the ON state and normal. If the heater 72 is abnormal (NO in step S600), the following steps are not executed.

In the next step S610, the control device 100 confirms whether the opening command of the solenoid valve 79 is output. If the opening command of the solenoid valve 79 is not output (NO in step S610), the following steps are not executed.

In the next step S620, the control device 100 compares the temperature rise amount (T2-T1) of the refrigerant with the threshold value Tth1. When it is determined that the temperature rise amount (T2-T1) of the refrigerant is smaller than the threshold value Tth1 (YES in step S620), the control device 100 proceeds to the process in step S640. When the temperature rise amount (T2-T1) of the refrigerant is equal to or higher than the threshold value Tth1 (NO in step S420), the control device 100 determines that the filling amount of the refrigerant is insufficient (step S630).

In step S640, the control device 100 determines whether or not the acquired temperatures T1 and T2 are lower than the threshold value Tth3. The threshold value Tth3 is a value for detecting that the refrigerant is overheated by the heater 72 because the refrigerant is not flowing in the bypass circuit BC, and is appropriately set based on the heating amount of the heater 72 and the like. For example, the threshold Tth1 is set to a small value of about 4 to 5 ° C, while the threshold Tth3 is set to a large value of about 80 ° C.

If it is determined in step S640 that any of the temperatures T1 and T2 is equal to or higher than the threshold value Tth3 (NO in step S640), the control device 100 determines that the solenoid valve 79 is closed and failed (step). S650). When it is determined in step S640 that the solenoid valve 79 is closed and failed, an alarm indicating that the solenoid valve is failed may be output.

On the other hand, if it is determined in step S640 that both the temperatures T1 and T2 are lower than the threshold value Tth3 (YES in step S640), the control device 100 determines that the solenoid valve 79 is operating normally. This ends the failure determination process.

As described above, in the second embodiment, the solenoid valve 79 is provided in the bypass circuit BC. Then, the solenoid valve 79 is opened during the control of the refrigerant filling amount, and the solenoid valve 79 is closed when the control of the refrigerant filling amount is not executed. This makes it possible to prevent the performance deterioration of the refrigerating apparatus caused by the continuous flow of the refrigerant through the bypass circuit BC during normal operation in which the refrigerant is not filled.

Further, in the second embodiment, the failure of the heater 72 is detected. This prevents the refrigerant from being erroneously determined that the refrigerant shortage has not occurred even though the refrigerant is not heated in the bypass circuit BC due to the failure of the heater 72. can.

Further, in the second embodiment, the closing failure of the solenoid valve 79 is detected. As a result, since the refrigerant does not flow in the bypass circuit BC due to the closing failure of the solenoid valve 79, it is possible to prevent an erroneous determination that the refrigerant shortage has not occurred even though the refrigerant shortage actually occurs. can.

Embodiment 3.
In the third embodiment, as the heat source in the refrigerant amount detection unit, a high-temperature and high-pressure refrigerant on the compressor outlet side is used instead of the heater 72. As a result, the refrigerant amount detection unit can be configured without separately providing the heater 72.

FIG. 16 is an overall configuration diagram of a refrigerating apparatus using the heat source side unit according to the third embodiment.

With reference to FIG. 16, the refrigerating apparatus 1B includes a heat source side unit 2B and a load side unit 3. The heat source side unit 2B includes the refrigerant amount detection unit 70B in place of the refrigerant amount detection unit 70A in the heat source side unit 2A of the second embodiment shown in FIG. In the refrigerant amount detection unit 70A of the second embodiment shown in FIG. 11, the refrigerant amount detection unit 70B includes a heat exchange unit 78 instead of the heater 72, and further includes temperature sensors 75 to 77.

The heat exchange unit 78 is configured to exchange heat between the high-temperature and high-pressure refrigerant discharged from the compressor 10 and the refrigerant that has passed through the capillary tube 71.

The temperature sensor 73 detects the temperature of the refrigerant on the upstream side of the heat exchange unit 78, that is, the temperature T1 of the refrigerant between the capillary tube 71 and the heat exchange unit 78. On the other hand, the temperature sensor 74 detects the temperature of the refrigerant on the downstream side of the heat exchange unit 78, that is, the temperature T2 of the refrigerant downstream of the heat exchange unit 78 and before merging with the pipe 85.

Further, the temperature sensor 75 detects the temperature T3 of the high-temperature and high-pressure refrigerant discharged from the compressor 10, and outputs the detected value to the control device 100. The temperature sensor 76 detects the temperature T4 of the refrigerant discharged from the compressor 10 and passed through the heat exchange unit 78, and outputs the detected value to the control device 100. That is, the temperature sensors 75 and 76 detect the temperature of the refrigerant before and after the passage of the heat exchange unit 78 for the refrigerant supplied from the compressor 10 to the condenser 20, respectively. The temperature sensor 77 detects the temperature T5 of the refrigerant sucked into the compressor 10 and outputs the detected value to the control device 100.

The control device 100 determines the appropriateness of the refrigerant filling amount in the refrigerating device 1B based on the temperature rise amount of the refrigerant when the refrigerant flowing through the pipe 87 is heated by the heat exchange unit 78. More specifically, the control device 100 determines that the refrigerant filling amount is insufficient when the temperature rise amount of the refrigerant by the heat exchange unit 78 becomes equal to or more than the threshold value.

Here, since the heating amount of the heat exchange unit 78 changes depending on the operating state of the refrigerating device 1B, the temperature rise amount of the refrigerant in the pipe 87 in the heat exchange unit 78 also changes depending on the operating state of the refrigerating device 1B. In particular, when the refrigerant is a non-azeotropic refrigerant, the temperature rises when the gas-liquid two-phase refrigerant flowing through the pipe 87 is heated in the heat exchange section 78, even if the refrigerant is not insufficient, and the amount of the temperature rise is increased. Depends on the amount of heating. Even if the refrigerant is an azeotropic refrigerant, the temperature of the refrigerant may rise if the heat exchange unit 78 has a large amount of heat.

Therefore, in the third embodiment, the heating amount of the heat exchange unit 78 is estimated, and the threshold value Tth6 (of the refrigerant in the heat exchange unit 78) for determining whether or not the refrigerant is insufficient is determined based on the heating amount. The threshold value for the amount of temperature rise) is set. As a result, even if the heating amount of the heat exchange unit 78 changes depending on the operating state of the refrigerating device 1B, the refrigerant shortage can be detected with high accuracy.

FIG. 17 is a flowchart showing a procedure for filling the refrigerant circuit RC with the refrigerant in the refrigerating apparatus of FIG.

The flowchart of FIG. 17 is a modification of the flowchart of FIG. In the flowchart of FIG. 17, steps S150, S152, S230, and S260 related to the heater in FIG. 13 are deleted. In step S170, it is determined whether or not a predetermined time (for example, 2 minutes) has elapsed since the solenoid valve 79 was opened. Further, step S194 for setting the threshold value Tth6 is executed between step S190 and step S200. Further, in step S200, the threshold value to be compared with the temperature rise amount (T2-T1) is changed to the threshold value Tth6 set in step S194 above. Since the other points of FIG. 17 are the same as those of FIG. 13, the description will not be repeated by assigning the same or similar reference numerals to the same or corresponding steps.

FIG. 18 is a flowchart showing a detailed procedure of step S194 for setting the threshold value of FIG.

In step S700, the control device 100 retrieves necessary data from the data stored in the buffer. Specifically, the control device 100 acquires the detected values of the temperatures T1 to T5 by the temperature sensors 73 to 77, the rotation speed R of the compressor 10, and the detected values of the pressure LPs and HPs of the pressure sensors 90 and 92.

In the next step S710, the control device 100 calculates the refrigerant flow rate G flowing from the compressor 10 to the heat exchange unit 78. Further, the control device 100 calculates the enthalpy difference H before and after the heat exchange unit 78 of the refrigerant flowing from the compressor 10 to the heat exchange unit 78.

Specifically, the refrigerant flow rate G (kg / hr) can be calculated by the following equation.
Refrigerant flow rate G = V × R × D… (8)
Here, V is the amount of push-out of the compressor 10 (m ³ ), that is, the amount of refrigerant sucked per revolution of the compressor. R is the rotation speed (1 / hr or 1 / s) of the compressor 10. D is the density of the refrigerant (kg / m ³ ). The density D is an amount determined by the temperature and pressure of the refrigerant on the suction side of the compressor 10, and can be calculated from the temperature T5 detected by the temperature sensor 77 and the pressure LP detected by the pressure sensor 90.

Further, the enthalpy difference H (kJ / kg) can be calculated by the following equation.
Enthalpy difference H = H3-H4 ... (9)
Here, H3 is the enthalpy of the refrigerant supplied from the compressor 10 to the heat exchange unit 78, and H4 is the enthalpy of the refrigerant after passing through the heat exchange unit 78.

FIG. 19 is a diagram for explaining a method of calculating enthalpy. With reference to FIG. 19, the enthalpy H3 is an amount determined by the discharge pressure of the compressor 10 and the refrigerant temperature before passing through the heat exchange unit 78. The enthalpy H3 can be obtained from the pressure HP detected by the pressure sensor 92 and the temperature T3 detected by the temperature sensor 75. Further, the enthalpy H4 is an amount determined by the discharge pressure of the compressor 10 and the refrigerant temperature after passing through the heat exchange unit 78. The enthalpy H4 can be obtained from the pressure HP and the temperature T4 detected by the temperature sensor 76.

With reference to FIG. 18 again, in the next step S720, the control device 100 calculates the heating amount of the heat exchange unit 78. Specifically, the heating amount (W = J / s) of the heat exchange unit 78 is calculated by, for example, the following equation.

Heating amount = G × H… (10)
In the next step S730, the control device 100 sets a threshold value Tth6 for determining whether or not a refrigerant shortage has occurred based on the calculated heating amount of the heat exchange unit 78. As described above, the threshold value Tth 6 is used in the heat exchange unit 78 to compare with the temperature rise amount of the refrigerant flowing through the pipe 87.

The relationship between the heating amount and the threshold value Tth6 is obtained in advance by preliminary evaluation, simulation, or the like according to the type of the refrigerant used, and is stored in the storage 106 of the control device 100. Qualitatively, the larger the heating amount, the larger the threshold value Tth6, and when the heating amount is the same, the threshold value of the non-azeotropic refrigerant is larger than the threshold value of the azeotropic refrigerant.

As described above, according to the third embodiment, as the heat source in the refrigerant amount detection unit 70B, a heat exchange unit 78 using a high-temperature and high-pressure refrigerant on the outlet side of the compressor 10 is provided instead of the heater 72. Therefore, the refrigerant amount detection unit can be configured without providing the heater 72.

Here, it should be noted that the heating amount of the heat exchange unit 78 changes depending on the operating state of the refrigerating apparatus 1B. According to the third embodiment, the threshold value Tth6 of the temperature rise amount of the refrigerant flowing through the pipe 87 in the heat exchange unit 78 is set based on the heat amount of the heat exchange unit 78. Therefore, even if the operating state of the refrigerating device 1A changes, it is possible to accurately detect the refrigerant shortage.

The refrigerating apparatus 1B shown in FIG. 16 can be changed so that the solenoid valve 79 is not provided. In this case, in the flowchart of FIG. 17, steps S154, S192, S235, and S265 related to the solenoid valve 79 are deleted. In step S170, it is determined whether or not a predetermined time (for example, 2 minutes) has elapsed since the operation of the compressor 10 was started.

Embodiment 4.
In the fourth embodiment, the content of step S210 for executing the additional filling of the refrigerant in the flowcharts of FIGS. 6, 13, and 17 of the first to third embodiments is changed. In the case of the first to third embodiments, as described with reference to FIG. 8, in step S210, the control device 100 changes the filling speed of the refrigerant according to the amount of temperature rise of the refrigerant (T2-T1). On the other hand, in the case of the fourth embodiment, the filling rate is changed based on the degree of supercooling and the temperature efficiency.

Here, the degree of supercooling is obtained by subtracting the outlet temperature OT of the supercooling heat exchanger 40 from the condensation temperature CT. The temperature efficiency ε is a value obtained by dividing the degree of supercooling of the refrigerant at the outlet of the supercooling heat exchanger 40 by the maximum temperature difference of the supercooling heat exchanger 40.

First, the relationship between the degree of supercooling and the temperature efficiency, which are the premise of the fourth embodiment, and the amount of the refrigerant filled in the refrigerant circuit will be described. This relationship has already been described with reference to FIG. 10, but the main points will be described below.

As shown in FIG. 10A, the degree of supercooling increases as the total amount of the refrigerant filled in the refrigerant circuit RC increases, and the degree of supercooling becomes a steady value after the appropriate amount of the refrigerant is filled. However, the value of the degree of supercooling when it reaches the steady value greatly differs depending on the operating conditions of the refrigerating apparatus. Therefore, the threshold value Sth of the degree of supercooling is set to a relatively small value so that the determination can be made under any operating conditions. As a result, the refrigerant filling amounts R1 and R2 when the degree of supercooling of the refrigerant exceeds the threshold Sth are considerably smaller than the refrigerant filling amount E when the temperature rise amount in the refrigerant amount detecting unit 70 becomes less than the threshold Tth1. ..

As shown in FIG. 10B, the temperature efficiency ε increases as the total amount of the refrigerant filled in the refrigerant circuit RC increases, and the temperature efficiency ε becomes a steady value after the appropriate amount of the refrigerant is filled. The value of the temperature efficiency ε when it reaches the steady value changes depending on the operating conditions of the refrigerating apparatus, but the amount of change is small. The threshold value εth is set in consideration of this slight difference in temperature efficiency ε depending on the operating conditions. As a result, the refrigerant filling amount R3 when the temperature efficiency ε exceeds the threshold value εth is slightly smaller than the refrigerant filling amount E when the temperature rise amount in the refrigerant amount detecting unit 70 becomes less than the threshold value Tth1.

In the fourth embodiment, the timing when the above-mentioned supercooling degree exceeds the threshold value Sth and the timing when the temperature efficiency ε exceeds the threshold value εth are used as the timing for switching the refrigerant filling speed. As a result, the refrigerant filling speed can be switched at a timing before the timing at which the temperature rise amount in the refrigerant amount detecting unit 70 becomes less than the threshold value Tth1. Hereinafter, a specific description will be given with reference to the drawings.

FIG. 20 is a flowchart showing a procedure for switching the filling rate in the additional filling in the fourth embodiment. The flowchart of FIG. 20 shows step S210 of FIGS. 6, 13, and 17 in more detail and is used instead of the flowchart of FIG. Further, each step of FIG. 20 is executed when T2-T1 <Tth1 is not satisfied in step S200 of FIGS. 6, 13, and 17 (NO in step S200).

With reference to FIG. 20, in step S800, the control device 100 calculates the degree of supercooling by subtracting the outlet temperature OT of the supercooling heat exchanger 40 from the condensation temperature CT. Then, the control device 100 determines whether or not the degree of supercooling (CT-OT) exceeds the threshold value Sth.

As a result of this determination, when the degree of supercooling is equal to or less than the threshold value Sth (NO in step S800), in step S810, the control device 100 instructs to start or continue filling the refrigerant at a high flow rate. As a result, the refrigerant can be continuously filled in the refrigerant circuit at a high flow rate up to a certain amount, so that the total time required for the refrigerant filling work can be shortened.

On the other hand, when the degree of supercooling exceeds the threshold value Sth (YES in step S800), the control device 100 advances the process to step S820. In step S820, the control device 100 calculates the temperature efficiency ε according to the above equation (7) using the condensation temperature CT, the outlet temperature OT of the supercooling heat exchanger 40, and the outside air temperature AT.

In the next step S830, the control device 100 determines whether or not the calculated temperature efficiency ε exceeds the threshold value εth. As a result of this determination, when the temperature efficiency ε is equal to or less than the threshold value εth (NO in step S830), the control device 100 proceeds to step S840. In step S840, the control device 100 instructs the refrigerant filling speed to be slower than in the case of step S810 (that is, supercooling degree ≦ Sth).

On the other hand, when the temperature efficiency ε is larger than the threshold value εth, the control device 100 proceeds to the process in step S850. In step S850, the control device 100 instructs the refrigerant filling rate to be further reduced than in the case of step S840 (that is, temperature efficiency ε ≦ εth). That is, if the refrigerant filling speed in the case of step S840 is medium, the filling speed in the case of step S850 is considerably slower than that. This makes it possible to prevent the refrigerant circuit RC from being overfilled with the refrigerant.

As described above, according to the fourth embodiment, as in the first to third embodiments, the refrigerant circuit RC is continuously filled with the refrigerant, and the filling is performed according to the increase in the filling amount of the refrigerant. It is controlled to slow down the speed. As a result, the time required for the filling operation can be shortened while preventing the refrigerant circuit RC from being overfilled with the refrigerant.

In the above, the filling speed of the refrigerant is switched to three stages, but it may be switched to two stages. In this case, the filling speed may be reduced when the degree of supercooling at the outlet of the supercooling heat exchanger 40 exceeds the threshold value Sth, or the filling speed may be reduced when the temperature efficiency ε exceeds εth. May be good.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope of the claims.

1,1A, 1B Refrigerator, 2,2A, 2B Heat source side unit, 3 Load side unit, 10 Compressor, 20 Condenser, 30 Receiver, 40 Overcooling heat exchanger, 50 Expansion valve, 60 Evaporator, 70, 70A, 70B Refrigerator amount detector, 71 capillary tube, 72 heater, 73-77 temperature sensor, 78 heat exchange unit, 79 electromagnetic valve, 80-87 piping, 90, 92 pressure sensor, 100 controller, 102 CPU, 104 memory, 106 storage, 120 output device, 122 input device, AT outside air temperature, BC bypass circuit, CT condensation temperature, ET evaporation temperature, HP high pressure side pressure (discharge pressure), LP low pressure side pressure (suction pressure), OT excess Cooling heat exchanger outlet temperature, RC refrigerant circuit.

Claims (16)

A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor and a condenser.
At least the expansion mechanism, the evaporator, the compressor, and the condenser constitute a refrigerant circuit that circulates the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant on the outlet side of the condenser to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs to fill the additional refrigerant when the temperature rise amount is equal to or more than the first threshold value.
When the temperature rise is less than the second threshold value larger than the first threshold value, the control device has a filling speed of the additional refrigerant as compared with the case where the temperature rise amount is greater than or equal to the second threshold value. Instructed to reduce,
The control device is instructed to stop the filling of the additional refrigerant when the amount of temperature rise is less than the first threshold value.
After stopping the filling of the additional refrigerant, the control device instructs the refrigerant circuit to further fill the insufficient amount of the refrigerant.
The heat source side unit is calculated based on the difference between the estimated maximum density of the refrigerant in one year and the density of the refrigerant at the time of filling . The heat source side unit further includes a liquid receiver and a supercooling heat exchanger.
The expansion mechanism, the evaporator, the compressor, the condenser, the liquid receiver, and the supercooling heat exchanger constitute the refrigerant circuit for circulating the refrigerant in order.
The heat source side unit according to claim 1 , wherein the bypass circuit is connected between the liquid receiver and the supercooled heat exchanger. The heat source side unit further includes a liquid receiver and a supercooling heat exchanger.
The expansion mechanism, the evaporator, the compressor, the condenser, the liquid receiver, and the supercooling heat exchanger constitute the refrigerant circuit for circulating the refrigerant in order.
The bypass circuit is connected between the liquid receiver and the supercooled heat exchanger.
The piping that constitutes the refrigerant circuit
A first pipe connecting the expansion mechanism and the supercooled heat exchanger,
A second pipe connecting the evaporator and the compressor is included.
The control device calculates the amount of insufficient refrigerant based on at least the refrigerant density and internal volume inside each of the condenser, the first pipe, the second pipe, the evaporator, and the liquid receiver. , The heat source side unit according to claim 1 . When the refrigerant circuit is filled with the refrigerant, the control device is instructed to fill the initial filling amount of the refrigerant necessary for operating the compressor, and after filling the initial filling amount of the refrigerant, the said 13 . Heat source side unit. The bypass circuit is further provided with an on-off valve provided in the bypass circuit and configured to switch the flow and cutoff of the refrigerant in the bypass circuit.
The control device controls the on-off valve to be in the open state when the refrigerant circuit is filled with the refrigerant, and controls the on-off valve to be in the closed state after completing the filling of the refrigerant in the refrigerant circuit. The heat source side unit according to any one of claims 1 to 4 . The heat source side unit according to any one of claims 1 to 5 , wherein the heater is a heater. The heat source side unit according to any one of claims 1 to 5 , wherein the heater is a refrigerant pipe on the outlet side of the compressor. A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor and a condenser.
At least the expansion mechanism, the evaporator, the compressor, and the condenser constitute a refrigerant circuit that circulates the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant on the outlet side of the condenser to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs to fill the additional refrigerant when the temperature rise amount is equal to or more than the first threshold value.
When the temperature rise is less than the second threshold value larger than the first threshold value, the control device has a filling speed of the additional refrigerant as compared with the case where the temperature rise amount is greater than or equal to the second threshold value. Instructed to reduce,
The heater is a refrigerant pipe on the outlet side of the compressor.
The control device is a heat source side unit that estimates the heating amount of the heater and changes the first threshold value according to the estimated heating amount . A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor and a condenser.
At least the expansion mechanism, the evaporator, the compressor, and the condenser constitute a refrigerant circuit that circulates the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant on the outlet side of the condenser to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs to fill the additional refrigerant when the temperature rise amount is equal to or more than the first threshold value.
When the temperature rise is less than the second threshold value larger than the first threshold value, the control device has a filling speed of the additional refrigerant as compared with the case where the temperature rise amount is greater than or equal to the second threshold value. Instructed to reduce,
The heater is a heater.
The control device has a temperature detected by at least one of the preheating temperature sensor and the postheating temperature sensor when the heater as the heater is turned on without flowing the refrigerant through the bypass circuit. However, when the temperature is less than the third threshold value, which is larger than the first threshold value, the heat source side unit determines that the heater has failed . A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor and a condenser.
At least the expansion mechanism, the evaporator, the compressor, and the condenser constitute a refrigerant circuit that circulates the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant on the outlet side of the condenser to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs to fill the additional refrigerant when the temperature rise amount is equal to or more than the first threshold value.
When the temperature rise is less than the second threshold value larger than the first threshold value, the control device has a filling speed of the additional refrigerant as compared with the case where the temperature rise amount is greater than or equal to the second threshold value. Instructed to reduce,
The heat source side unit further includes an on-off valve provided in the bypass circuit and configured to switch the flow and cutoff of the refrigerant in the bypass circuit.
The control device controls the on-off valve to be in the open state when the refrigerant circuit is filled with the refrigerant, and after completing the filling of the refrigerant into the refrigerant circuit, controls the on-off valve to be in the closed state.
In the control device, when the refrigerant is heated by the heater with the on-off valve controlled to be open, the temperature detected by at least one of the preheating temperature sensor and the postheating temperature sensor is determined. A heat source side unit that determines that the on-off valve is closed and failed when the fourth threshold value larger than the first threshold value is exceeded . The heat source side unit according to any one of claims 1 to 10, wherein the refrigerant amount detecting unit is provided at a position where the influence of the air flow is small as compared with the condenser. The control device averages the temperature rises obtained at a plurality of time points when determining the magnitude of the temperature rise and the first threshold value, and the averaged temperature rise is temporal. The heat source side unit according to any one of claims 1 to 11, which continuously determines whether or not the temperature is less than the first threshold value. A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor, a condenser, a liquid receiver, and a supercooled heat exchanger.
The expansion mechanism, the evaporator, the compressor, the condenser, the liquid receiver, and the supercooling heat exchanger constitute a refrigerant circuit for circulating the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant flowing from the condenser to the receiver to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs the refrigerant circuit to be filled with an additional refrigerant when the amount of temperature increase is equal to or greater than the first threshold value.
The control device is instructed to reduce the filling rate of the additional refrigerant when the temperature efficiency exceeds the fifth threshold value as compared with the case where the temperature efficiency is equal to or less than the fifth threshold value.
The temperature efficiency is a value obtained by dividing the degree of supercooling of the refrigerant at the outlet of the supercooled heat exchanger by the maximum temperature difference of the supercooled heat exchanger, which is a heat source side unit. In the control device, when the temperature efficiency is equal to or less than the fifth threshold value and the degree of supercooling of the refrigerant exceeds the sixth threshold value, the temperature efficiency is equal to or less than the fifth threshold value and the refrigerant is present. The heat source side unit according to claim 13 , wherein the supercooling degree of the above is instructed to reduce the filling rate of the additional refrigerant as compared with the case where the degree of supercooling is equal to or less than the sixth threshold value. A heat source side unit that is connected to the load side unit to form a refrigeration cycle device.
The load-side unit includes a refrigerant expansion mechanism and an evaporator.
The heat source side unit includes a compressor, a condenser, a liquid receiver, and a supercooled heat exchanger.
The expansion mechanism, the evaporator, the compressor, the condenser, the liquid receiver, and the supercooling heat exchanger constitute a refrigerant circuit for circulating the refrigerant in order.
The heat source side unit further
A bypass circuit configured to return a part of the refrigerant flowing from the condenser to the receiver to the compressor without passing through the evaporator.
A heater configured to heat the refrigerant flowing in the bypass circuit, a post-heated temperature sensor that detects the temperature of the refrigerant heated by the heater, and the temperature of the refrigerant before being heated by the heater. Refrigerant amount detector including pre-heating temperature sensor to detect
Equipped with a control device,
The control device calculates the difference between the temperature detected by the post-heating temperature sensor and the temperature detected by the pre-heating temperature sensor as the amount of temperature rise.
When the refrigerant circuit is filled with the refrigerant, the control device instructs the refrigerant circuit to be filled with an additional refrigerant when the amount of temperature increase is equal to or greater than the first threshold value.
The control device adds the above when the degree of supercooling of the refrigerant at the outlet of the overcooling heat exchanger exceeds the sixth threshold value, as compared with the case where the degree of supercooling of the refrigerant is equal to or less than the sixth threshold value. A heat source side unit that directs the reduction of the refrigerant filling rate. The heat source side unit according to any one of claims 1 to 15 .
A refrigeration cycle device including a load side unit connected to the heat source side unit.

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