WO2024080213A1 - Method for filling heat transport device with refrigerant and refrigerant filling control device for heat transport device - Google Patents

Abstract

This method for filling a heat transport device (110) with a refrigerant comprises: a pre-filling step (step 902) for filling a refrigerant flow path (10) of a heat transport device (110) with an inactive gas such that the pressure inside the refrigerant flow path (10) of the heat transport device (110) reaches a prescribed pressure; and a main filling step (step 904) for filling the refrigerant flow path (10) of the heat transport device (110) with a refrigerant to a prescribed quantity necessary for operating the heat transport device (110), after the pre-filling step (step 902).

Description

Method for filling refrigerant into heat transport device and refrigerant filling control device for heat transport device

The present invention relates to a method for filling a heat transport device with a refrigerant and a refrigerant filling control device for a heat transport device.

　Conventionally, devices that control a closed loop that operates according to a thermodynamic cycle are known. Such a device is disclosed, for example, in Japanese Patent No. 6660095.

　The above-mentioned Patent No. 6,660,095 describes a device that controls a closed loop in which heat is exchanged with an external heat source by compressing and expanding a working fluid, which is a heat medium, using a Rankine cycle as a thermodynamic cycle. This closed loop includes a pump for circulating and compressing the working fluid, and a tank that holds the liquid working fluid to be fed into the pump. A pressure source of pressurized gas is connected to the tank via a pressure regulating valve. In order to prevent the occurrence of cavitation, which generates gas in the pump, the device described in the above-mentioned Patent No. 6,660,095 controls the operation of the pressure regulating valve during the operation of the closed loop to allow gas to flow in from the pressure source separately from the working fluid, thereby pressurizing the inside of the tank.

Japanese Patent No. 6660095

However, in the device described in the above-mentioned Patent Publication No. 6,660,095, a gas (inert gas) is introduced from a pressure source separately from the refrigerant into a closed loop flow path (refrigerant flow path) filled with a working fluid (refrigerant), thereby pressurizing the refrigerant. In this case, it is difficult to grasp the inlet amount (charge amount) of the inert gas into the refrigerant flow path, because the inert gas dissolves in the refrigerant in a liquid phase, and the amount of inert gas that dissolves in the refrigerant varies depending on the temperature and pressure of the refrigerant. Since the evaporation and condensation temperatures of the refrigerant vary depending on the charge amount of the inert gas, it is desirable to easily grasp the charge amount of the inert gas that is charged separately from the refrigerant in a heat transport device using a thermodynamic cycle.

This invention was made to solve the problems described above, and one objective of the invention is to provide a method for filling a refrigerant into a heat transport device using a thermodynamic cycle, which makes it easy to grasp the amount of inert gas that is filled separately from the refrigerant, and a refrigerant filling control device for the heat transport device.

The method for filling a refrigerant into a heat transport device in a first aspect of the present invention includes a pre-filling step of filling the refrigerant flow path of the heat transport device with an inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure, and a main filling step of filling the refrigerant flow path of the heat transport device with refrigerant up to a predetermined amount required for operation of the heat transport device after the pre-filling step. Note that the term "heat transport device" is used here as a concept that includes a cooling device that cools an object and a heating device that heats an object.

In a second aspect of the present invention, the refrigerant charging control device for a heat transport device includes a control unit that performs control to obtain the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit, and the control unit performs control to determine whether charging of the inert gas is complete based on the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit when performing pre-charging, in which an inert gas is charged into the refrigerant flow path of the heat transport device so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure, before performing main charging, in which refrigerant is charged into the refrigerant flow path of the heat transport device up to a predetermined amount required for operation of the heat transport device.

In the method for filling a refrigerant into a heat transport device in the first aspect of the present invention, the refrigerant flow path of the heat transport device is filled with an inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure, and then the main filling is performed to fill the refrigerant flow path of the heat transport device with the refrigerant up to a predetermined amount required for the operation of the heat transport device. In addition, in the refrigerant filling control device for a heat transport device in the second aspect of the present invention, before the main filling, the refrigerant flow path of the heat transport device is filled with an inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure. This makes it possible to suppress the difficulty in grasping the amount of inert gas filled due to the inert gas dissolving in the refrigerant, unlike the case where the inert gas is filled after the refrigerant is filled. As a result, in a heat transport device using a thermodynamic cycle, the amount of inert gas filled separately from the refrigerant can be easily grasped. In addition, in the present invention, since the inert gas is filled before the main filling of the refrigerant into the refrigerant flow path, the pressure of the inert gas required for filling can be reduced compared to the case where the inert gas is filled after the refrigerant is filled. Therefore, since there is no need to provide a relatively high-pressure inert gas source, the inert gas can be easily filled into the refrigerant flow path.

FIG. 1 is a schematic diagram illustrating a cooling system that uses an inert gas along with carbon dioxide refrigerant. 4 is a flowchart showing a process of a method for filling a refrigerant into a cooling device according to the first embodiment. FIG. 13 is a schematic diagram showing the configuration of a refrigerant charging control device and a cooling device according to a second embodiment. 10 is a flowchart showing a process of a method for filling a cooling device with a refrigerant according to a second embodiment. FIG. 13 is a schematic diagram showing the configuration of a refrigerant charging control device and a cooling device according to a third embodiment. 13 is a flowchart showing a process of a method for filling a cooling device with a refrigerant according to a fourth embodiment.

Below, an embodiment of the present invention will be described with reference to the drawings.

[First embodiment]
First, as a first embodiment, a method for filling a cooling device 110 (heat transport device) with a refrigerant (carbon dioxide refrigerant) performed by an operator will be described with reference to FIGS. 1 and 2. FIG.

(Configuration of the cooling device)
The cooling device 110 (see FIG. 1) is a cooling device that uses carbon dioxide as a refrigerant. The cooling device 110 is a device that performs cooling using carbon dioxide in a gas-liquid two-phase state in which gas and liquid are mixed. The cooling device 110 includes a condenser 1, a tank 2, a pump 3, an evaporator 4, and a device control unit 5. The cooling device 110 pressurizes the refrigerant carbon dioxide with an inert gas to prevent cavitation from occurring in the pump 3. Cavitation is the generation of gas in the pump 3 arranged in the refrigerant flow path 10 of the cooling device 110 during operation of the cooling device 110. When the pressure of the liquid-phase refrigerant flowing into the pump 3 becomes smaller than the saturated vapor pressure in the pump 3, gas is generated, causing cavitation. The inert gas is filled by a preset amount so that the pressure of the refrigerant flowing into the pump 3 arranged in the refrigerant flow path 10 of the cooling device 110 becomes equal to or higher than the saturated vapor pressure of the refrigerant during operation of the cooling device 110. The cooling device 110 is an example of a "heat transport device" in the claims.

In the cooling device 110, a refrigerant flow path 10 is formed by a condenser 1, a tank 2, a pump 3, an evaporator 4, and piping connected to each of the condenser 1, the tank 2, the pump 3, and the evaporator 4.

Condenser 1 condenses the refrigerant (carbon dioxide). Condenser 1 is configured to cool and condense the refrigerant using a chiller. The refrigerant flowing out of condenser 1 is sent to tank 2. Tank 2 is a container that stores the refrigerant. The refrigerant condensed by condenser 1 flows into tank 2. Tank 2 stores the refrigerant that has become a liquid or a two-phase gas-liquid state. The refrigerant stored in tank 2 is sent to pump 3. Tank 2 also stores an inert gas along with the refrigerant.

The pump 3 sends the refrigerant (carbon dioxide) stored in the tank 2 to the evaporator 4. The operation of the pump 3 is controlled by the device control unit 5. The evaporator 4 cools a cooling target (not shown) by evaporating the refrigerant discharged from the pump 3. The refrigerant flowing out of the evaporator 4 is then returned to the condenser 1, where it is condensed.

The device control unit 5 is configured to control the entire cooling device 110. The device control unit 5 includes a processor such as a CPU (Central Processing Unit), memory, etc. The device control unit 5 is configured to control the entire cooling device 110 using control software (programs) recorded (stored) in an internal or external memory (storage device).

The cooling device 110 is equipped with temperature sensors 61 and 62 that detect the temperature of the refrigerant in the refrigerant flow path. The cooling device 110 is also equipped with pressure sensors 63 and 64 that detect the pressure in the refrigerant flow path. Note that the pressure sensors 63 and 64 are an example of the "pressure detection unit" in the claims.

The temperature sensor 61 is disposed between the tank 2 and the pump 3, and detects the temperature of the refrigerant flowing out of the tank 2. The temperature sensor 62 is disposed between the evaporator 4 and the condenser 1, and detects the temperature of the refrigerant flowing out of the evaporator 4.

The pressure sensor 63 is disposed between the tank 2 and the pump 3, and detects the pressure of the refrigerant flowing between the tank 2 and the pump 3. The pressure sensor 64 is disposed between the evaporator 4 and the condenser 1, and detects the pressure of the refrigerant flowing between the evaporator 4 and the condenser 1.

The device control unit 5 is also connected to communicate with the pump 3. The device control unit 5 is also connected to communicate with each of the temperature sensors 61 and 62. The device control unit 5 is also connected to communicate with each of the pressure sensors 63 and 64.

The device control unit 5 is configured to acquire the detection signals of the temperature sensor 61, the temperature sensor 62, the pressure sensor 63, and the pressure sensor 64, and control the cooling device 110.

In addition, cylinder 121, cylinder 122, and vacuum pump 123 are each connected to refrigerant flow path 10 of cooling device 110 via manifold 7.

The cylinder 121 is filled with carbon dioxide (refrigerant). A flow rate control valve 81 is provided between the cylinder 121 and the manifold 7. The flow rate control valve 81 adjusts the opening degree to adjust the flow rate of carbon dioxide flowing out of the cylinder 121.

The cylinder 122 is filled with an inert gas. The cylinder 122 is filled with, for example, nitrogen. A flow control valve 82 is provided between the cylinder 122 and the manifold 7. The flow control valve 82 adjusts the flow rate of the inert gas (nitrogen) flowing out of the cylinder 122 by adjusting its opening.

The vacuum pump 123 is a pump for drawing a vacuum inside the refrigerant flow path of the cooling device 110. Note that in this specification, "vacuum" does not mean an absolute vacuum, but rather means a state in which a specific space is filled with gas at a pressure lower than atmospheric pressure.

The manifold 7 is connected to the refrigerant flow path 10 of the cooling device 110. Specifically, the flow path inside the manifold 7 is connected to the piping upstream of the tank 2 (the piping between the tank 2 and the condenser 1). In addition, the manifold 7 is connected to piping that connects to each of the cylinders 121 and 122 and the vacuum pump 123. The manifold 7 can switch the piping to which the refrigerant flow path 10 is connected by adjusting the opening of the valves 7a and 7b to close and open the flow paths formed inside. This allows the manifold 7 to switch between introducing carbon dioxide (refrigerant) into the refrigerant flow path 10, introducing an inert gas into the refrigerant flow path 10, and drawing a vacuum (exhaust) inside the refrigerant flow path 10.

(Refrigerant charging method according to the first embodiment)
With reference to FIG. 2, a process flow (steps 901 to 904) of the method for charging the cooling device 110 with the refrigerant according to the first embodiment will be described.

First, in step 901, the worker draws a vacuum inside the refrigerant flow path 10. The worker operates the manifold 7 ( valves 7a and 7b) and the vacuum pump 123 to draw a vacuum inside the piping between the refrigerant flow path 10 and the cylinders 121 and 122. After completing the vacuum drawing inside the refrigerant flow path 10, the worker performs the work of step 902.

In step 902, the worker performs pre-filling. In step 902, the worker pre-fills the refrigerant flow path 10 of the cooling device 110 with an inert gas, and then fills the refrigerant flow path 10 of the cooling device 110 with carbon dioxide at a filling rate that suppresses the generation of dry ice (solid) so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide. That is, before the refrigerant flow path 10 is filled with carbon dioxide, the inert gas is filled into the refrigerant flow path 10. As described above, the inert gas is filled into the refrigerant flow path 10 to prevent cavitation from occurring in the pump 3. Note that the filling amount (set amount) of the inert gas required to prevent cavitation differs depending on the performance of the pump 3. That is, the pressure in the refrigerant flow path 10 after the inert gas required to prevent cavitation is filled into the refrigerant flow path 10 differs depending on the performance of the pump 3. The inert gas is filled by a preset filling amount (set amount) so that the pressure in the refrigerant flow path 10 of the cooling device 110 becomes a predetermined pressure at which cavitation does not occur. In the first embodiment, the pressure in the refrigerant flow path 10 after filling with the inert gas is less than the triple point pressure of carbon dioxide.

In the first embodiment, in step 902 (pre-filling), before filling the refrigerant flow path 10 with carbon dioxide, an inert gas is pre-filled into the refrigerant flow path 10 that has been evacuated. When pre-filling the refrigerant flow path 10 that has been evacuated with an inert gas, dry ice is not generated. Therefore, by pre-filling the inert gas, the pressure in the refrigerant flow path 10 can be easily increased to approach the triple point pressure of carbon dioxide, compared to the case where the refrigerant flow path 10 that has been evacuated is gradually filled with carbon dioxide and the pressure in the refrigerant flow path 10 is gradually increased. As a result, by pre-filling the refrigerant flow path 10 that has been evacuated with an inert gas and then filling the refrigerant flow path 10 with carbon dioxide, the pressure in the refrigerant flow path 10 can be easily increased to or above the triple point pressure of carbon dioxide, without generating dry ice, compared to the case where the refrigerant flow path 10 that has been evacuated is filled with carbon dioxide and then filled with an inert gas.

In step 902, the operator fills the refrigerant flow path 10 of the cooling device 110 with carbon dioxide at a filling rate that suppresses the generation of dry ice, so that the pressure inside the refrigerant flow path 10 of the cooling device 110 is equal to or greater than the triple point pressure of carbon dioxide (0.52 MPa-a). That is, the operator fills the refrigerant flow path 10 of the cooling device 110, which is in a state where the internal pressure is less than the triple point pressure of carbon dioxide (0.52 MPa-a) and is filled with inert gas, with carbon dioxide, so that the internal pressure is equal to or greater than the triple point pressure of carbon dioxide (0.52 MPa-a). For example, carbon dioxide is filled so that the pressure inside the refrigerant flow path 10 of the cooling device 110 changes from a state where the pressure is less than the triple point pressure of carbon dioxide (0.52 MPa-a) to 0.7 MPa-a or greater. Note that step 902 is an example of a "pre-filling step" in the claims.

Note that the carbon dioxide filling rate in step 902 (pre-filling) is lower than the carbon dioxide filling rate in step 904 (main filling) described below. Note that the ratio of the carbon dioxide filling rate in pre-filling to the carbon dioxide filling rate in main filling depends on the internal volume of the cooling device 110 (refrigerant flow path 10). The operator adjusts the opening of valve 7a and flow control valve 81 of manifold 7 to gradually fill carbon dioxide into refrigerant flow path 10 so that dry ice does not form in the refrigerant flow path 10.

In step 903, the worker checks whether the temperature in the refrigerant flow path 10 of the cooling device 110 is within a predetermined temperature range. The worker checks the temperature in the refrigerant flow path 10 detected by the temperature sensors 61 and 62. The worker then checks that no dry ice has been generated in the refrigerant flow path 10 based on the temperature in the refrigerant flow path 10 detected by the temperature sensors 61 and 62. The worker may check the temperature in the refrigerant flow path 10 using a display unit and a gauge (meter) (not shown) provided in the cooling device 110, or may check the temperature in the refrigerant flow path 10 using a filling device as in the second embodiment described below.

If the temperature in the refrigerant flow path 10 of the cooling device 110 is not within the predetermined temperature range, the operator waits until the temperature in the refrigerant flow path 10 of the cooling device 110 is within the predetermined temperature range. Then, if the temperature in the refrigerant flow path 10 of the cooling device 110 is within the predetermined temperature range, the operator starts the main charging of carbon dioxide (step 904).

In other words, step 904 is started when the temperature in the refrigerant flow path 10 of the cooling device 110 falls within a predetermined temperature range. Note that step 904 is an example of the "main filling step" in the claims.

In step 904, the worker performs the actual filling of carbon dioxide. Specifically, the worker fills the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for operation of the cooling device 110, while the pressure inside the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide. Specifically, the worker adjusts the opening of the valve 7a and the flow control valve 81 of the manifold 7 to fill the refrigerant flow path 10 with the predetermined amount of carbon dioxide required for operation of the cooling device 110.

(Effects of the First Embodiment)
In the first embodiment, the following effects can be obtained.

In the first embodiment, the inert gas is filled into the refrigerant flow path 10 of the cooling device 110 (heat transport device) so that the pressure in the refrigerant flow path 10 of the cooling device 110 becomes a predetermined pressure, and then the refrigerant is filled into the refrigerant flow path 10 of the cooling device 110 to a predetermined amount required for the operation of the cooling device 110. This makes it possible to suppress the difficulty in grasping the amount of inert gas filled due to the inert gas dissolving in the refrigerant, unlike the case where the inert gas is filled after the refrigerant is filled. As a result, in the cooling device 110 using a thermodynamic cycle, the amount of inert gas filled separately from the refrigerant can be easily grasped. In addition, in the first embodiment, the inert gas is filled before the refrigerant is filled into the refrigerant flow path 10, so the pressure of the inert gas required for filling can be reduced compared to the case where the inert gas is filled after the refrigerant is filled. Therefore, since there is no need to provide a relatively high-pressure inert gas source, the inert gas can be easily filled into the refrigerant flow path 10.

In addition, by filling the refrigerant flow path 10 with inert gas up to a predetermined pressure, the amount of inert gas filled can be determined, making it easier to determine the amount of inert gas filled compared to measuring the amount filled based on the weight of the inert gas. In particular, when the amount of inert gas required is small, it may be difficult to measure the amount filled based on weight, so by filling the refrigerant flow path 10 with inert gas up to a predetermined pressure, the amount of inert gas filled can be determined more effectively.

In the first embodiment, the pre-filling step (step 902) fills the cooling device 110 (heat transport device) with inert gas to a predetermined pressure that does not cause cavitation, which generates gas in the pump 3 arranged in the refrigerant flow path 10 of the cooling device 110 when the cooling device 110 (heat transport device) is in operation. With this configuration, the amount of inert gas filled can be easily determined by filling the inert gas in the pre-filling step (step 902) prior to step 904 in which the refrigerant (carbon dioxide) is actually filled, and therefore, by filling the inert gas in the pre-filling step to a predetermined pressure that does not cause cavitation, the amount of inert gas filled to prevent cavitation can be effectively and easily determined.

In the first embodiment, the pre-filling step (step 902) fills the refrigerant flow path 10 of the cooling device 110 with inert gas so that the pressure inside the refrigerant flow path 10 of the cooling device 110 becomes a predetermined pressure so that the pressure of the refrigerant (carbon dioxide) flowing into the pump 3 arranged in the refrigerant flow path 10 of the cooling device 110 (heat transport device) becomes equal to or higher than the saturated vapor pressure of the refrigerant when the cooling device 110 (heat transport device) is in operation. With this configuration, since the inert gas is filled in the pre-filling step (step 902), it is possible to more effectively and easily grasp that the inert gas has been filled by the amount of filling (set amount) set so that the pressure of the refrigerant flowing into the pump 3 becomes equal to or higher than the saturated vapor pressure of the refrigerant when the cooling device 110 is in operation.

In the first embodiment, the pre-filling step (step 902) fills in nitrogen as an inert gas so that the pressure in the refrigerant flow path 10 of the cooling device 110 (heat transport device) becomes a predetermined pressure. With this configuration, by filling nitrogen, a relatively stable substance, as the inert gas, the occurrence of cavitation due to the inert gas can be more stably suppressed. Therefore, by filling nitrogen as the inert gas in the pre-filling step (step 902), the operation of the cooling device 110 can be more stabilized, and the amount of inert gas to be filled to further stabilize the operation of the cooling device 110 can be more effectively and easily grasped.

In the first embodiment, the refrigerant flow path 10 of the cooling device 110 (heat transport device) is pre-filled with an inert gas, and then carbon dioxide (refrigerant) is pre-filled into the evacuated refrigerant flow path 10 of the cooling device 110 at a filling rate that suppresses the generation of dry ice (solid) so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide. This allows the main filling of filling the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for the operation of the cooling device 110 with carbon dioxide, with the pressure in the refrigerant flow path 10 being equal to or higher than the triple point pressure of carbon dioxide. As a result, during the main filling of carbon dioxide, carbon dioxide can be filled into the refrigerant flow path 10 at a pressure state in which dry ice is not generated, and therefore the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice can be suppressed without heating or cooling the carbon dioxide. As a result, unlike when carbon dioxide is heated or cooled during filling, there is no need to add a device for heating or cooling the carbon dioxide, so it is possible to prevent the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice while suppressing the complexity of the device configuration for filling the refrigerant flow path 10 of the cooling device 110 with carbon dioxide refrigerant.

In addition, the method of filling the cooling device 110 (heat transport device) with refrigerant according to the first embodiment described above can be carried out as follows to obtain the following additional effects.

In the first embodiment, the main filling step (step 904) is started based on the temperature in the refrigerant flow path 10 of the cooling device 110 (heat transport device) reaching a temperature within a predetermined temperature range. This allows the main filling of carbon dioxide to be started after it has been confirmed that no temperature drop due to the generation of dry ice has occurred in the refrigerant flow path 10. As a result, it is possible to more effectively prevent the refrigerant flow path 10 from becoming clogged due to the generation of dry ice during the main filling of carbon dioxide.

In addition, in the first embodiment, the carbon dioxide filling rate in the pre-filling step (step 902) is lower than the carbon dioxide filling rate in the main filling step (step 904). This makes it possible to suppress a sudden drop in temperature of the carbon dioxide due to adiabatic expansion, compared to when the carbon dioxide filling rate in the pre-filling step and the carbon dioxide filling rate in the main filling step are approximately the same. As a result, it is possible to suppress the carbon dioxide from turning into dry ice due to a sudden drop in temperature due to adiabatic expansion in the refrigerant flow path 10. In addition, since the carbon dioxide filling rate in the main filling step is higher than the carbon dioxide filling rate in the pre-filling step, the time required for the main filling of carbon dioxide can be shortened. As a result, the time required to fill carbon dioxide to a predetermined amount required for the operation of the cooling device 110 (heat transport device) can be shortened.

[Second embodiment]
As a second embodiment, a method of filling a cooling device 110 with a refrigerant in which the refrigerant filling control device 100 displays a message to prompt an operator to fill the cooling device 110 with a refrigerant will be described with reference to FIGS. 3 and 4.

The refrigerant charging control device 100 includes a control unit 101 and a display unit 102. The refrigerant charging control device 100 is an example of a "refrigerant charging control device for a heat transport device" as claimed. The display unit 102 is an example of a "notification unit" as claimed.

The control unit 101 is configured to control the entire refrigerant charging control device 100. The control unit 101 includes a processor such as a CPU, a memory, etc. The control unit 101 is configured to control the charging of the carbon dioxide refrigerant into the cooling device 110 by control software (programs) recorded (stored) in an internal or external memory (storage device).

The control unit 101 controls the acquisition of the temperature of the refrigerant flowing through the refrigerant flow path 10 of the cooling device 110, which is detected by the temperature sensors 61 and 62. The control unit 101 controls the acquisition of the pressure of the refrigerant flowing through the refrigerant flow path 10 of the cooling device 110, which is detected by the pressure sensors 63 and 64. In other words, the control unit 101 controls the acquisition of the pressure within the refrigerant flow path 10 of the cooling device 110, which is detected by the pressure sensors 63 and 64.

The display unit 102 displays (informs) the pressure of the refrigerant flowing through the refrigerant flow path 10 of the cooling device 110, which is acquired by the control unit 101. The display unit 102 also displays (informs) the temperature of the refrigerant flowing through the refrigerant flow path 10 of the cooling device 110, which is acquired by the control unit 101. In other words, the display unit 102 displays (informs) information for filling the refrigerant (carbon dioxide) into the refrigerant flow path 10 of the cooling device 110. The display unit 102 includes a liquid crystal display or an organic EL display. The display unit 102 may also include a gauge (meter).

The control unit 101 performs control to determine whether or not pre-filling is completed, in which an inert gas and a refrigerant (carbon dioxide) are filled into the evacuated refrigerant flow path 10 of the cooling device 110 so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or greater than the triple point pressure of carbon dioxide. In the second embodiment, when performing pre-filling, the control unit 101 performs control to determine whether or not pre-filling is completed based on the pressure of the refrigerant flowing through the refrigerant flow path 10 of the cooling device 110 (pressure in the refrigerant flow path 10) detected by the pressure sensors 63 and 64.

Specifically, when pre-filling is performed to fill the inert gas to a predetermined pressure before the main filling, the control unit 101 performs control to determine whether or not the filling of the inert gas is completed based on the pressure in the refrigerant flow path 10 of the cooling device 110 detected by the pressure sensors 63 and 64. For example, the control unit 101 pre-stores a value of a predetermined pressure in pre-filling of the inert gas corresponding to a filling amount at which cavitation does not occur. Then, while the inert gas is being filled in pre-filling, the control unit 101 determines whether or not the filling of the inert gas is completed based on whether or not the pressure in the refrigerant flow path 10 detected by the pressure sensors 63 and 64 has risen to a predetermined pressure. Thereafter, the control unit 101 similarly determines whether or not the filling of the refrigerant in pre-filling is completed based on whether or not the pressure in the refrigerant flow path 10 (the pressure of the refrigerant flowing through the refrigerant flow path 10) detected by the pressure sensors 63 and 64 has risen to a value equal to or higher than the triple point pressure of the refrigerant that is previously set.

The control unit 101 also determines whether the temperature in the refrigerant flow path 10 of the cooling device 110 is within a predetermined temperature range after pre-filling. Specifically, the control unit 101 determines whether the temperature in the refrigerant flow path 10 detected by the temperature sensors 61 and 62 is within a predetermined temperature range. For example, the control unit 101 determines whether the difference in the temperatures in the refrigerant flow path 10 detected by each of the temperature sensors 61 and 62 is within less than a few degrees Celsius. The control unit 101 may also determine whether all of the temperatures in the refrigerant flow path 10 detected by each of the temperature sensors 61 and 62 are within the predetermined temperature range.

When the control unit 101 determines that pre-filling is complete, it controls the actual filling of the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for the operation of the cooling device 110, while the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide.

In the second embodiment, when the control unit 101 determines that the filling of the inert gas is completed in the pre-filling, the control unit 101 causes the display unit 102 to display (report) information indicating that the filling of the inert gas is completed. For example, the control unit 101 controls the display unit 102 to display a sentence (characters) such as "The filling of the inert gas is completed." The control unit 101 also causes the display unit 102 to display (report) the pressure in the refrigerant flow path 10 of the cooling device 110 acquired from the pressure sensors 63 and 64 as information indicating that the filling of the inert gas is completed. The control unit 101 also causes the display unit 102 to display (report) a sentence (characters) encouraging the filling of carbon dioxide (refrigerant) in the pre-filling, together with the information indicating that the filling of the inert gas is completed.

In the second embodiment, when the temperature in the refrigerant flow path 10 of the cooling device 110 falls within a predetermined temperature range after pre-filling, the control unit 101 controls the display unit 102 to display (notify) a message urging the operator to start main filling, as control related to performing main filling. For example, the control unit 101 controls the display unit 102 to display a sentence (characters) such as "Please start main filling." This causes the refrigerant filling control device 100 (display unit 102) to urge the operator to start main filling.

In the second embodiment, the operator operates the manifold 7 (valve 7a) and the flow rate control valve 81 based on the display of the display unit 102 to fill the refrigerant flow path 10 with carbon dioxide (refrigerant).

(Refrigerant charging method according to the second embodiment)
A process flow of a method for charging a refrigerant into a cooling device 110 (heat transport device) according to the second embodiment will be described with reference to Fig. 4. In the method for charging a refrigerant into a cooling device 110 according to the second embodiment, the processes of steps 931 to 934 are performed in the pre-charging step of step 902 in Fig. 2. The processes of steps 901, 903, and 904 are the same as those in the first embodiment.

In step 931, in pre-filling, inert gas is filled. Then, in step 932, it is determined whether the inert gas has been filled to a predetermined pressure at which cavitation does not occur, based on the pressure in the refrigerant flow path 10 detected by the pressure sensors 63 and 64. If it is determined that the inert gas has been filled to the predetermined pressure, information indicating that filling with inert gas is complete is displayed on the display unit 102, and the process proceeds to step 933. If it is not determined that the inert gas has been filled to the predetermined pressure, the process waits until the predetermined pressure is reached.

Then, in step 933, the refrigerant (carbon dioxide) is charged in the pre-fill. Then, in step 934, it is determined whether the refrigerant has been charged to a pressure equal to or greater than the triple point pressure, based on the pressure in the refrigerant flow path 10 detected by the pressure sensors 63 and 64. For example, it is determined whether the refrigerant has been charged to 0.7 MPa-a or more, which is equal to or greater than the triple point pressure. If it is determined that the refrigerant (carbon dioxide) in the pre-fill has been charged to the triple point pressure or more, the process proceeds to step 903. If it is not determined that the refrigerant (carbon dioxide) has been charged to the triple point pressure or more, the process is put on hold.

In addition, in the process flow of the method of filling the cooling device 110 with refrigerant according to the second embodiment, in step 903, after the display unit 102 displays (notifies), the operator checks the temperature inside the refrigerant flow path 10. The rest of the process flow is the same as the process flow in the first embodiment.

(Effects of the Second Embodiment)
In the second embodiment, the following effects can be obtained.

In the second embodiment, the control unit 101 fills the refrigerant flow path 10 of the cooling device 110 (heat transport device) with inert gas before the main filling so that the pressure in the refrigerant flow path 10 of the cooling device 110 (heat transport device) becomes a predetermined pressure. As a result, unlike the case of filling the inert gas after filling the refrigerant, as in the first embodiment, it is possible to suppress the difficulty in grasping the amount of inert gas filled due to the inert gas dissolving in the refrigerant. As a result, in the cooling device 110 using a thermodynamic cycle, it is possible to easily grasp the amount of inert gas filled separately from the refrigerant. Also, in the second embodiment, as in the first embodiment, there is no need to provide a relatively high-pressure inert gas source, so the inert gas can be easily filled into the refrigerant flow path.

In addition, in the second embodiment, when pre-filling is performed before actual filling, the control unit 101 performs control to determine whether or not filling with inert gas is complete based on the pressure in the refrigerant flow path 10 of the cooling device 110 (heat transport device) detected by the pressure sensors 63 and 64. This allows the inert gas to be filled more accurately than when a person determines whether or not filling with inert gas is complete by visually checking a gauge (meter) or the like.

In the second embodiment, the control unit 101 can control the main filling of the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for the operation of the cooling device 110 (heat transport device) after the pressure in the refrigerant flow path 10 is made equal to or higher than the triple point pressure of carbon dioxide by pre-filling. As a result, during the main filling of carbon dioxide, carbon dioxide can be filled into the refrigerant flow path 10 at a pressure state where dry ice is not generated, and the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice can be suppressed without heating or cooling the carbon dioxide. As a result, unlike the case where carbon dioxide is heated or cooled during filling with carbon dioxide, there is no need to add a device for heating or cooling the carbon dioxide, so the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice can be suppressed while suppressing the complication of the device configuration for filling the refrigerant flow path 10 of the cooling device 110 with the carbon dioxide refrigerant. In addition, the operator can easily understand whether the pressure in the refrigerant flow path 10 is equal to or higher than the triple point pressure of carbon dioxide by the display of the display unit 102 (notification unit) that displays (notifies) the pressure of the refrigerant flowing through the refrigerant flow path 10.

In addition, the refrigerant charging control device 100 according to the second embodiment described above can achieve the following additional effects by being configured as follows:

In the second embodiment, the refrigerant charging control device 100 includes a display unit 102 (notification unit) that notifies information for charging the refrigerant flow path 10 of the cooling device 110 (heat transport device) with carbon dioxide (refrigerant). When the control unit 101 determines that charging of the inert gas is complete, the control unit 101 notifies information indicating that charging of the inert gas is complete via the display unit 102. With this configuration, an operator can easily recognize that charging of the inert gas is complete by recognizing the information indicating that charging of the inert gas is complete, which is notified by the display unit 102.

In addition, in the second embodiment, the control unit 101 controls the display unit 102 (notification unit) to notify the acquired pressure in the refrigerant flow path 10 of the cooling device 110 (heat transport device) as information indicating that the filling of the inert gas has been completed. With this configuration, the worker can easily recognize the specific value indicating the magnitude of the pressure in the refrigerant flow path 10 by recognizing the information indicating that the filling of the inert gas has been completed, which is notified by the display unit 102. Therefore, the worker can easily confirm that the inert gas has been filled up to a predetermined pressure.

In the second embodiment, the control unit 101 judges whether the temperature in the refrigerant flow path 10 of the cooling device 110 (heat transport device) is within a predetermined temperature range after pre-filling. When the temperature in the refrigerant flow path 10 of the cooling device 110 is within the predetermined temperature range, the control unit 101 controls the display unit 102 (notification unit) to display (notify) the operator to perform the main filling. This allows the operator to visually check (confirm) the display by the display unit 102 and easily confirm that no temperature drop due to the generation of dry ice has occurred in the refrigerant flow path 10. In addition, the operator can start the main filling of carbon dioxide after confirming from the display by the display unit 102 that no temperature drop due to the generation of dry ice has occurred in the refrigerant flow path 10. As a result, it is possible to more effectively prevent the refrigerant flow path 10 from being blocked due to the generation of dry ice during the main filling of carbon dioxide.

The other effects of the second embodiment are the same as those of the first embodiment.

[Third embodiment]
A method of charging the cooling device 110 with a refrigerant in the third embodiment will be described. In the third embodiment, a refrigerant charging control device 200 (see FIG. 5) automatically performs pre-charging of the cooling device 110 with an inert gas and carbon dioxide, and main charging of the cooling device 110 with carbon dioxide. The refrigerant charging control device 200 is an example of a "refrigerant charging control device for a heat transport device" in the claims.

The control unit 101 of the refrigerant charging control device 200 is configured to control each of the manifold 7 ( valves 7a and 7b), the flow rate control valve 81, the flow rate control valve 82, and the vacuum pump 123. As a result, the work that was performed by an operator in the first and second embodiments is performed automatically under the control of the control unit 101 of the refrigerant charging control device 200.

In the third embodiment, for example, the control unit 101 draws a vacuum in the refrigerant flow path 10 by controlling the operation of the vacuum pump 123 and the manifold 7. The control unit 101 then controls the operation of the manifold 7 and the flow rate control valve 82 to start filling with inert gas and start pre-filling. If the control unit 101 determines that filling with inert gas is complete during pre-filling, it controls the operation of the manifold 7 and the flow rate control valve 82 to stop filling with inert gas. The control unit 101 then controls the operation of the manifold 7 and the flow rate control valve 81 to fill with refrigerant by pre-filling, thereby completing pre-filling.

In the third embodiment, when the temperature in the refrigerant flow path 10 of the cooling device 110 falls within a predetermined temperature range, the control unit 101 controls the filling of carbon dioxide as control related to the main filling. Specifically, when the temperature in the refrigerant flow path 10 of the cooling device 110 falls within a predetermined temperature range after pre-filling, the control unit 101 controls the manifold 7 (valve 7a) and the flow rate adjustment valve 81 to allow the carbon dioxide filled in the cylinder 121 to flow into the refrigerant flow path 10.

The rest of the configuration of the third embodiment is the same as that of the second embodiment. The process flow of the method of charging the cooling device 110 with refrigerant according to the third embodiment is the same as that of the first embodiment, except that the refrigerant charging control device 200 automatically performs each step instead of the operator.

(Effects of the Third Embodiment)
In the third embodiment, the following effects can be obtained.

In the third embodiment, the control unit 101 performs control to stop the filling of the inert gas when it is determined that the filling of the inert gas has been completed. With this configuration, even when the inert gas is automatically filled under the control of the control unit 101, the amount of the inert gas filled can be easily and accurately grasped by filling the inert gas before the refrigerant by pre-filling. Therefore, the control unit 101 can fill the inert gas more easily and accurately.

Furthermore, in the third embodiment, as in the second embodiment, it is possible to suppress the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice while suppressing the complexity of the device configuration for filling the refrigerant flow path 10 of the cooling device 110 (heat transport device) with carbon dioxide refrigerant.

In addition, the refrigerant charging control device 200 according to the third embodiment described above can achieve the following additional effects by configuring it as follows:

In the third embodiment, the control unit 101 judges whether the temperature in the refrigerant flow path 10 of the cooling device 110 (heat transport device) is within a predetermined temperature range after pre-charging. When the temperature in the refrigerant flow path 10 of the cooling device 110 is within the predetermined temperature range, the control unit 101 controls the charging of carbon dioxide as a control for performing the main charging. This allows the control unit 101 to control the charging of carbon dioxide (main charging) after confirming that no temperature drop due to the generation of dry ice has occurred in the refrigerant flow path 10. As a result, the blocking of the refrigerant flow path 10 due to the generation of dry ice during the main charging of carbon dioxide can be more effectively suppressed. In addition, since the control unit 101 automatically controls the charging of carbon dioxide (main charging), the control unit 101 can start the control of the charging of carbon dioxide (main charging) more quickly than when an operator starts the main charging of carbon dioxide after confirming that no temperature drop due to the generation of dry ice has occurred in the refrigerant flow path 10.

The other effects of the third embodiment are the same as those of the first embodiment.

[Fourth embodiment]
A method of charging the cooling device 110 with carbon dioxide refrigerant in the fourth embodiment will be described.

The fourth embodiment is a method for charging the cooling device 110 with carbon dioxide refrigerant in the case where the pressure in the refrigerant flow path 10 can be increased to or above the triple point pressure of carbon dioxide when the amount of inert gas required to prevent cavitation in the pump 3 is charged. In the method for charging the cooling device 110 with carbon dioxide refrigerant in the fourth embodiment, pre-charging is performed using only inert gas, unlike the first embodiment in which inert gas and carbon dioxide are charged during pre-charging.

(Method of charging carbon dioxide refrigerant according to the fourth embodiment)
With reference to FIG. 6, a process flow (steps 911 to 913) of the method for charging the cooling device 110 with the carbon dioxide refrigerant according to the fourth embodiment will be described.

First, in step 911, the worker draws a vacuum inside the refrigerant flow path 10. After the refrigerant flow path 10 has been drawn a vacuum, the worker performs the work of step 912. Note that step 911 is the same process as step 901 in the first embodiment.

In step 912, the worker pre-fills with inert gas. In step 912, the worker fills the evacuated refrigerant flow path 10 of the cooling device 110 with inert gas so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide (0.52 MPa-a). For example, the worker fills the refrigerant flow path 10 of the cooling device 110 with inert gas so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than 0.7 MPa-a. That is, in the fourth embodiment, the predetermined pressure of the inert gas that does not cause cavitation, which is filled in pre-filling, is higher than the triple point pressure of the refrigerant. In other words, at the point in time when the inert gas is filled up to the predetermined pressure at which cavitation does not occur, the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide (0.52 MPa-a). Note that step 912 is an example of a "pre-filling step" in the claims.

In step 913, the worker performs the main filling of carbon dioxide. Specifically, the worker fills the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for the operation of the cooling device 110, with the pressure in the refrigerant flow path 10 of the cooling device 110 being equal to or higher than the triple point pressure of carbon dioxide. In the fourth embodiment, only an inert gas (nitrogen) is filled in the pre-filling, so dry ice is not generated during the pre-filling. Therefore, after the pre-filling is completed, the main filling can be performed without checking the temperature in the refrigerant flow path 10. Note that, in consideration of the temperature drop in the refrigerant flow path 10 due to the adiabatic expansion of the inert gas, the temperature in the refrigerant flow path 10 may be checked after the pre-filling (step 912) as in the first embodiment. Note that step 913 is an example of a "main filling step" in the claims.

(Effects of the Fourth Embodiment)
In the fourth embodiment, the following effects can be obtained.

In the fourth embodiment, a pre-filling is performed by filling the evacuated refrigerant flow path 10 of the cooling device 110 (heat transport device) with an inert gas so that the pressure in the refrigerant flow path 10 of the cooling device 110 is equal to or higher than the triple point pressure of carbon dioxide. This allows the main filling to be performed by filling the refrigerant flow path 10 of the cooling device 110 with carbon dioxide up to a predetermined amount required for the operation of the cooling device 110 with carbon dioxide while keeping the pressure in the refrigerant flow path 10 equal to or higher than the triple point pressure of carbon dioxide. As a result, during the main filling of carbon dioxide, carbon dioxide can be filled into the refrigerant flow path 10 at a pressure state where dry ice is not generated, so that the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice can be suppressed without heating or cooling the carbon dioxide. This allows the occurrence of blockage of the refrigerant flow path 10 due to the generation of dry ice to be suppressed while suppressing the complexity of the device configuration for filling the refrigerant flow path 10 of the cooling device 110 with carbon dioxide refrigerant.

[Modification]
It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

For example, in the above second embodiment, the control unit 101 of the refrigerant charging control device 100 performs control to acquire the pressure of the refrigerant flowing through the refrigerant flow path 10 detected by the pressure sensors 63 and 64 (pressure detection unit) provided in the cooling device 110 (heat transport device), but the present invention is not limited to this. In the present invention, the refrigerant charging control device may be provided with a pressure detection unit, and the control unit of the refrigerant charging control device may perform control to acquire the pressure of the refrigerant flowing through the refrigerant flow path detected by the pressure detection unit of the refrigerant charging control device. The control unit of the refrigerant charging control device may then perform control related to charging the carbon dioxide refrigerant based on the detection result of the pressure detection unit provided in the refrigerant charging control device.

In the above second embodiment, the control unit 101 of the refrigerant charging control device 100 performs control to obtain the temperature of the refrigerant flowing through the refrigerant flow path 10 detected by the temperature sensors 61 and 62 provided in the cooling device 110 (heat transport device), but the present invention is not limited to this. In the present invention, the refrigerant charging control device may be provided with a temperature sensor, and the control unit of the refrigerant charging control device may perform control to obtain the temperature of the refrigerant flowing through the refrigerant flow path detected by the temperature sensor of the refrigerant charging control device. The control unit of the refrigerant charging control device may then perform control related to the charging of the carbon dioxide refrigerant based on the detection result of the temperature sensor provided in the refrigerant charging control device.

In the above second embodiment, an example has been shown in which the display unit 102 (alert unit) performs control to display (alert) a message urging the operator to perform main refilling, but the present invention is not limited to this. In the present invention, the alert unit may use sound to alert the operator to perform main refilling. Note that, when the alert unit is a display unit that uses visual information to alert, the display unit may be a backlit indicator or a display using micro LEDs, rather than a liquid crystal display, organic EL display, or gauge (meter). The alert unit may be configured to perform both auditory alerts using sound and visual alerts using a display unit, etc.

In the fourth embodiment, the carbon dioxide refrigerant is charged by an operator without using the refrigerant charging control device 100 or 200, but the present invention is not limited to this. In the present invention, even in a carbon dioxide refrigerant charging method in which an inert gas is charged into the evacuated refrigerant flow path of a heat transport device so that the pressure in the refrigerant flow path of the heat transport device is equal to or higher than the triple point pressure of carbon dioxide, the refrigerant charging control device 100 may control the display unit 102 (notification unit) to display (notify) the operator to perform the main charging, as in the second embodiment. Note that, when the main charging is performed without checking the temperature in the refrigerant flow path after the completion of pre-charging, as in the fourth embodiment, the control unit of the refrigerant charging control device controls the notification by the notification unit based on the fact that the pressure in the refrigerant flow path of the cooling device (heat transport device) has become equal to or higher than the triple point pressure of carbon dioxide. In addition, as in the third embodiment, the refrigerant charging control device 200 may automatically perform some or all of the steps in the carbon dioxide refrigerant charging method, which involves pre-charging the evacuated refrigerant flow path of the heat transport device with an inert gas so that the pressure in the refrigerant flow path of the heat transport device is equal to or greater than the triple point pressure of carbon dioxide.

In the third embodiment, the control unit 101 of the refrigerant charging control device 200 controls the charging of carbon dioxide as control related to the main charging when the temperature in the refrigerant flow path 10 of the cooling device 110 (heat transport device) falls within a predetermined temperature range, but the present invention is not limited to this. In the present invention, the refrigerant charging control device may be equipped with an operation unit such as a touch panel, keyboard, or mouse, and the control unit of the refrigerant charging control device may control the charging of carbon dioxide (main charging) based on input operations by an operator to the operation unit. Also, the cooling flow path may be evacuated or pre-charged by the control of the control unit of the refrigerant charging control device based on input operations by an operator to the operation unit.

In addition, in the second and third embodiments, the refrigerant charging control device 100 and the refrigerant charging control device 200 are provided separately from the device control unit 5, but the present invention is not limited to this. In the present invention, the control performed by the refrigerant charging control device 100 and the refrigerant charging control device 200 may be performed by the device control unit 5.

In addition, in the above first to fourth embodiments, an example was shown in which the flow path inside the manifold 7 is connected to the piping upstream of the tank 2 (the piping between the tank 2 and the condenser 1), but the present invention is not limited to this. In the present invention, the flow path inside the manifold 7 may be connected to a piping of the refrigerant flow path 10 other than the piping upstream of the tank 2 (the piping between the tank 2 and the condenser 1).

In addition, in the above first to fourth embodiments, for convenience of explanation, the carbon dioxide refrigerant filling method of the present invention has been explained using a flow-driven flowchart in which processing is performed in sequence according to a processing flow, but the present invention is not limited to this. In the present invention, the work (processing operations) in the carbon dioxide refrigerant filling method may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the work (processing operations) in the carbon dioxide refrigerant filling method may be performed completely event-driven, or may be performed by combining event-driven and flow-driven operations.

In the above first to fourth embodiments, the refrigerant flow path 10 is filled with nitrogen as an inert gas, and then carbon dioxide is filled as a refrigerant, but the present invention is not limited to this. In the present invention, the refrigerant is not limited to carbon dioxide, and fluorocarbon may be used as the refrigerant, or natural refrigerants such as ammonia and water may be used as the refrigerant. The inert gas is not limited to nitrogen, and the inert gas may be a rare gas, a fluorocarbon, or carbon dioxide. The air may be used as the inert gas. Also, before performing pre-filling, vacuuming may not be performed. That is, the refrigerant flow path at atmospheric pressure may be filled with inert gas up to a predetermined pressure. Also, when a refrigerant other than carbon dioxide is used, if no solid is generated during refrigerant filling, pre-filling may be completed and main filling may be performed regardless of whether the pressure is equal to or higher than the triple point pressure. That is, even if the predetermined pressure at which the inert gas is filled in pre-filling is lower than the triple point pressure of the refrigerant, main filling of the refrigerant may be started when filling of the inert gas is completed. That is, steps 933 and 934 in FIG. 4 may be omitted. In this case, the temperature inside the refrigerant flow path may not be measured. In other words, step 903 in FIG. 4 may be omitted.

In the above first to fourth embodiments, an example was shown in which the inert gas is filled into the refrigerant flow path 10 in pre-filling so that the pressure of the refrigerant flowing into the pump 3 during operation of the cooling device 110 (heat transport device) is equal to or greater than the saturated vapor pressure of the refrigerant, and so that cavitation does not occur. However, the present invention is not limited to this. In the present invention, a predetermined pressure may be set as the amount of inert gas filled in pre-filling so that the pressure of the refrigerant flowing into the pump 3 during operation of the heat transport device is equal to or greater than the saturated vapor pressure of the combined refrigerant and inert gas.

In addition, in the above first to fourth embodiments, an example was shown in which the refrigerant flow path 10 of the cooling device 110 (heat transport device) was filled with an inert gas and carbon dioxide (refrigerant), but the present invention is not limited to this. In the present invention, in a heating device serving as a heat transport device, the refrigerant flow path may be filled with an inert gas and a refrigerant.

In addition, in the above first to fourth embodiments, an example was shown that includes a pre-filling step (step 902) that includes filling with an inert gas, and a main filling step (step 904) that fills with a refrigerant (carbon dioxide), but the present invention is not limited to this. The present invention may further include a step of filling the refrigerant flow path of the heat transport device with refrigeration oil. The step of filling with refrigeration oil may be performed before the pre-filling step, after the pre-filling step, or after filling with an inert gas during the pre-filling step. The step of filling with refrigeration oil may also be performed after the main filling step.

In addition, in the above first to fourth embodiments, an example was shown in which the cooling device 110 (heat transport device) is equipped with a tank 2 that stores a refrigerant, but the present invention is not limited to this. In the present invention, the heat transport device may be configured to include an accumulator instead of a tank.

[Aspects]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

(Item 1)
a pre-charging step of charging an inert gas into the refrigerant passage of the heat transport device so that a pressure in the refrigerant passage of the heat transport device becomes a predetermined pressure;
a main filling step of filling the refrigerant into the refrigerant passage of the heat transport device with a predetermined amount of refrigerant required for operation of the heat transport device after the pre-filling step.

(Item 2)
2. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step fills the refrigerant with the inert gas so that the pressure reaches the predetermined pressure at which cavitation, which generates gas, does not occur in a pump disposed in the refrigerant flow path of the heat transport device during operation of the heat transport device.

(Item 3)
3. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step includes filling the inert gas so that a pressure in the refrigerant flow path of the heat transport device becomes the predetermined pressure so that a pressure of the refrigerant flowing into the pump disposed in the refrigerant flow path of the heat transport device during operation of the heat transport device becomes equal to or higher than a saturated vapor pressure of the refrigerant.

(Item 4)
4. The method for filling a refrigerant into a heat transport device according to any one of claims 1 to 3, wherein the pre-filling step fills the refrigerant flow path of the heat transport device with nitrogen as the inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes the predetermined pressure.

(Item 5)
5. The method for filling a refrigerant into a heat transport device according to any one of claims 1 to 4, wherein the pre-filling step comprises pre-filling the refrigerant flow path of the heat transport device with the inert gas so that the inside of the refrigerant flow path of the heat transport device is at the predetermined pressure, and then filling the refrigerant into the refrigerant flow path of the heat transport device at a filling rate that suppresses generation of solids, so that the pressure in the refrigerant flow path of the heat transport device is equal to or higher than the triple point pressure of the refrigerant.

(Item 6)
a control unit that controls acquisition of a pressure in a refrigerant flow path of the heat transport device detected by the pressure detection unit;
The control unit is a refrigerant filling control device for a heat transport device, which performs control to determine whether filling of the inert gas is completed based on the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit when pre-filling is performed by filling the refrigerant flow path of the heat transport device with an inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure before performing main filling in which refrigerant is filled into the refrigerant flow path of the heat transport device up to a predetermined amount required for operation of the heat transport device.

(Item 7)
7. The refrigerant charging control device for a heat transport device according to claim 6, wherein the control unit performs control to stop charging of the inert gas when it is determined that charging of the inert gas has been completed.

(Item 8)
a notification unit that notifies information for filling the refrigerant into the refrigerant flow path of the heat transport device,
8. The refrigerant filling control device for a heat transport device according to claim 6 or 7, wherein when it is determined that the filling of the inert gas is completed, the control unit notifies the notification unit of information indicating that the filling of the inert gas is completed.

(Item 9)
Item 9. A refrigerant filling control device for a heat transport device as described in item 8, wherein the control unit controls the notification unit to notify the acquired pressure in the refrigerant flow path of the heat transport device as information indicating that filling of the inert gas is completed.

(Item 10)
A refrigerant filling control device for a heat transport device described in any one of items 6 to 9, wherein when the control unit determines that the pre-filling is completed based on the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit, the control unit controls the main filling to fill the refrigerant into the refrigerant flow path of the heat transport device up to a predetermined amount required for operation of the heat transport device.

10 Coolant flow path 63, 64 Pressure sensor (pressure detection unit)
100, 200 Refrigerant charging control device 101 Control unit 102 Display unit (notification unit)
110 Cooling device (heat transport device)

Claims (10)

1. a pre-charging step of charging an inert gas into the refrigerant passage of the heat transport device so that a pressure in the refrigerant passage of the heat transport device becomes a predetermined pressure;
   a main filling step of filling the refrigerant into the refrigerant passage of the heat transport device with a predetermined amount of refrigerant required for operation of the heat transport device after the pre-filling step.
2. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step fills the inert gas to the predetermined pressure at which cavitation, which generates gas, does not occur in a pump disposed in the refrigerant flow path of the heat transport device during operation of the heat transport device.
3. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step fills the inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes the predetermined pressure, so that the pressure of the refrigerant flowing into a pump arranged in the refrigerant flow path of the heat transport device during operation of the heat transport device becomes equal to or higher than the saturated vapor pressure of the refrigerant.
4. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step fills the refrigerant flow path of the heat transport device with nitrogen as the inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes the predetermined pressure.
5. The method for filling a refrigerant into a heat transport device according to claim 1, wherein the pre-filling step includes pre-filling the refrigerant flow path of the heat transport device with the inert gas so that the pressure inside the refrigerant flow path of the heat transport device is the predetermined pressure, and then filling the refrigerant into the refrigerant flow path of the heat transport device at a filling speed that suppresses the generation of solids, so that the pressure inside the refrigerant flow path of the heat transport device is equal to or higher than the triple point pressure of the refrigerant.
6. a control unit that controls acquisition of a pressure in a refrigerant flow path of the heat transport device detected by the pressure detection unit;
   The control unit is a refrigerant filling control device for a heat transport device, which performs control to determine whether filling of the inert gas is completed based on the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit when pre-filling is performed by filling the refrigerant flow path of the heat transport device with an inert gas so that the pressure in the refrigerant flow path of the heat transport device becomes a predetermined pressure before performing main filling in which refrigerant is filled into the refrigerant flow path of the heat transport device up to a predetermined amount required for operation of the heat transport device.
7. The refrigerant charging control device for a heat transport device according to claim 6, wherein the control unit performs control to stop charging of the inert gas when it is determined that charging of the inert gas is completed.
8. a notification unit that notifies information for filling the refrigerant into the refrigerant flow path of the heat transport device,
   7. The refrigerant filling control device for a heat transport device as described in claim 6, wherein the control unit, when it determines that the filling of the inert gas is completed, notifies the notification unit of information indicating that the filling of the inert gas is completed.
9. The refrigerant charging control device for a heat transport device according to claim 8, wherein the control unit controls the notification unit to notify the acquired pressure in the refrigerant flow path of the heat transport device as information indicating that the charging of the inert gas has been completed.
10. The refrigerant charging control device for a heat transport device according to claim 6, wherein the control unit, when determining that the pre-charging is complete based on the pressure in the refrigerant flow path of the heat transport device detected by the pressure detection unit, controls the main charging to charge the refrigerant into the refrigerant flow path of the heat transport device up to a predetermined amount required for the operation of the heat transport device.

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