Cooling system

Abstract

A cooling system according to one embodiment of the present invention is provided with: a refrigerant flow device (10) that includes a refrigerant flow path (11) through which a refrigerant flows, and a control valve (14) that is provided in the refrigerant flow path (11) and that controls the flow of the refrigerant; and a decompression device (20) that includes an introduction port (20A) that is connected to the downstream end (11D) of the refrigerant flow path (11) and that sucks gas from the refrigerant flow path (11), and an outflow port (20B) that is connected to the upstream end (11U) of the refrigerant flow path (11) and that causes the gas suctioned from the introduction port (20A) to flow into the refrigerant flow path (11) from the upstream end (11U) of the refrigerant flow path (11). The refrigerant circulation device (10) circulates the refrigerant contained in the gas flowing in from the pressure reducing device (20). Furthermore, the refrigerant circulation device (10) has a temperature control unit (16), which cools the temperature-controlled object by means of the refrigerant, on the downstream side of the control valve (14) in the refrigerant flow path (11).

Description

Technical Field

[0001] Embodiments of the present invention relate to a cooling system that utilizes the temperature drop of the refrigerant caused by depressurization. Background Technology

[0002] Vapor compression refrigeration devices are widely used in many fields.

[0003] In a vapor compression refrigeration system, the refrigerant is compressed by the compressor, and the refrigerant flowing out of the compressor is cooled by the condenser. The refrigerant flowing out of the condenser expands in the expansion valve, and the refrigerant flowing out of the expansion valve exchanges heat with the temperature-controlled object in the evaporator. The refrigerant is cooled by absorbing heat from the temperature-controlled object in the evaporator. The refrigerant flowing out of the evaporator circulates in the compressor, and then releases heat in the condenser.

[0004] The refrigerant used in vapor compression refrigeration systems is typically a fluorinated refrigerant. Fluorinated refrigerants are greenhouse gases and sometimes flammable, but they offer various advantages, such as high operating efficiency.

[0005] On the other hand, considering the environmental impact of fluorinated refrigerants (greenhouse effect), the development of fluorinated refrigerants for vapor compression applications that can suppress the Global Warming Potential (GWP) to a low level has been ongoing. Furthermore, HFO-based refrigerants for vapor compression applications with very low GWPs have already been put into practical use. Specifically, HFO-based refrigerants with a GWP of 10 or less have been put into practical use. However, the safety of these refrigerants cannot be fully guaranteed regarding their flammability and toxicity. Therefore, the development of vapor compression refrigerants that can ensure both low GWP and safety is currently prevalent.

[0006] Furthermore, the compressors used in vapor compression refrigeration systems operate continuously. Therefore, lubricating oil is required to lubricate the rotating parts and other drive components. However, there is a problem of lubricating oil leaking into the refrigerant side. Moreover, this leakage can sometimes cause oil shortages in the compressor, and may compromise the stability of its operation. Additionally, lubricating oil retention in the evaporator can sometimes impair its cooling efficiency. Therefore, there is room for improvement in the use of compressors in vapor compression refrigeration systems.

[0007] On the other hand, as a cooling device that does not use a compressor, boiling cooling devices disclosed in, for example, JP2011-142298A, WO2017 / 119113A and JP2021-162195A are known.

[0008] Boiling cooling devices efficiently cool the temperature-controlled object by vaporizing the liquid during heat exchange with it, utilizing the latent heat of heat for absorption. Furthermore, while pumps are typically required to circulate the liquid or its vaporized form, these pumps require little or no lubrication. Additionally, the energy consumption of the pumps is relatively low. Therefore, boiling cooling devices can be considered to have excellent environmental performance.

[0009] However, in boiling cooling devices, cooling is typically not possible in temperature ranges significantly below 0°C, and the cooling temperature and temperature control parameters are highly limited. Therefore, it is difficult to ensure high cooling capacity in low or ultra-low temperature ranges using boiling cooling devices. Summary of the Invention

[0010] In recent years, as mentioned above, the development of refrigerants with low environmental impact, such as HFO-based refrigerants, has been underway. On the other hand, the development of antifreeze with low environmental impact has also been ongoing. Furthermore, HFO-based solvents with low GWP and non-flammability, suitable for use as antifreeze, have been put into practical use. However, such solvents have boiling points above 70°C at atmospheric pressure, making them unsuitable for vapor compression refrigeration systems. Nevertheless, if thermal cycling can be achieved using such HFO-based solvents, it may be possible to realize a cooling system that ensures the currently strongly demanded low environmental impact, high safety, and high cooling capacity.

[0011] Therefore, the inventors of this application have conducted in-depth research in order to realize a new cooling system capable of using HFO-based solvents, such as those described above, as refrigerants in thermal cycling. More generally, in order to realize a new cooling system capable of converting substances from a range different from those usable in vapor compression refrigeration devices into refrigerants usable in thermal cycling, the present invention has been completed. Furthermore, it was discovered that by utilizing decompression to lower the temperature of the refrigerant and then using the refrigerant to cool the temperature-controlled object, the heat absorbed by the refrigerant is released at atmospheric pressure, thereby realizing the above-described cooling system.

[0012] That is, the objective of the present invention is to provide a cooling system that can use substances that have not been used in conventional refrigeration methods as refrigerants for thermal cycling, or can expand the range of substances that can be used as refrigerants for thermal cycling.

[0013] One embodiment of the present invention relates to the following methods "1" to "10".

[0014] [1] A cooling system comprising: a refrigerant flow device including a refrigerant flow path and a control valve, the refrigerant flow path allowing refrigerant to flow, the control valve being disposed in the refrigerant flow path to control the flow of the refrigerant; and a pressure reducing device including an inlet and an outlet, the inlet being connected to a downstream end of the refrigerant flow path for drawing gas from the refrigerant flow path, the outlet being connected to an upstream end of the refrigerant flow path for the gas drawn from the inlet to flow into the refrigerant flow path from the upstream end of the refrigerant flow path, the refrigerant flow path allowing the refrigerant contained in the gas flowing in from the pressure reducing device to flow, the refrigerant flow device having a temperature control unit downstream of the control valve in the refrigerant flow path, the temperature control unit using the refrigerant to cool a temperature-controlled object.

[0015] [2] According to the cooling system described in [1], the refrigerant flow device has a gas-liquid separator on the downstream side of the temperature control section in the refrigerant flow path, which separates the gas phase portion from the liquid phase portion in such a way that the gas phase portion of the refrigerant that has passed through the temperature control section flows downstream in a manner that makes the liquid phase portion flow downstream in a manner that makes the gas phase portion flow downstream in a manner that makes the liquid ...

[0016] [3] According to the cooling system of [1] or [2], wherein the refrigerant flow device has a storage tank upstream of the control valve in the refrigerant flow path, the storage tank storing the refrigerant in liquid phase that flows from the pressure reducing device into the refrigerant flow path, and the control valve controlling the flow of the liquid phase refrigerant flowing from the storage tank.

[0017] [4] According to the cooling system of [3], the storage tank has a cooler that cools the gas flowing in from the pressure reducing device, thereby liquefying the refrigerant from the gas.

[0018] [5] The cooling system according to any one of [1] to [4], wherein the refrigerant flow device has a double-laminar flow separator between the control valve and the temperature control unit in the refrigerant flow path, the double-laminar flow separator having an inlet and an outlet, the inlet allowing the refrigerant from the control valve to flow in, and the outlet being located below the inlet to allow the refrigerant flowing in from the inlet to flow out.

[0019] [6] The cooling system according to any one of [1] to [5], wherein the portion between the control valve and the temperature control unit in the refrigerant flow path and the downstream portion of the temperature control unit in the refrigerant flow path constitute an internal heat exchanger, which enables the refrigerant flowing in the two portions to exchange heat with each other.

[0020] [7] The cooling system according to any one of [1] to [6], wherein, by the operation of the pressure reducing device and the throttling state of the control valve, a state is formed in which the internal pressure of the downstream portion of the control valve in the refrigerant flow path is lower than the internal pressure of the upstream portion of the control valve in the refrigerant flow path.

[0021] [8] The cooling system according to any one of [1] to [7], wherein the refrigerant is a substance with a boiling point of 30°C or higher at atmospheric pressure.

[0022] [9] The cooling system according to any one of [1] to [8], wherein the GWP of the refrigerant is 10 or less.

[0023]

[10] The cooling system according to any one of [1] to [9], wherein the refrigerant is HFO-1336mzz-Z.

[0024] According to the present invention, substances that have not been used in conventional refrigeration methods can be used as refrigerants for thermal cycles, or the range of substances that can be used as refrigerants for thermal cycles can be expanded. Attached Figure Description

[0025] Figure 1 This is a diagram that schematically illustrates one embodiment of a cooling system.

[0026] Figure 2 It shows the composition Figure 1 A block diagram of the functional structure of the controller for the cooling system.

[0027] Figure 3 Is Figure 1 A pH graph of an example of a refrigerant used in a cooling system.

[0028] Figure 4 yes Figure 1 An example of the application of the cooling system is a schematic diagram of a plasma etching apparatus having the cooling system.

[0029] Figure 5 yes Figure 1 An example of the application of the cooling system is a schematic diagram of a cooking appliance with the cooling system.

[0030] Figure 6 yes Figure 1 An example of the application of the cooling system is a schematic diagram of a molding apparatus having the cooling system.

[0031] Figure 7 yes Figure 1An example of the application of the cooling system is a schematic diagram of a cold storage warehouse equipped with the cooling system.

[0032] Figure 8 This is a diagram that schematically illustrates the cooling system of a modified example. Detailed Implementation

[0033] The following describes one implementation method.

[0034] Figure 1 This is a schematic diagram of a cooling system S according to one embodiment. First, the structure of the cooling system S will be described.

[0035] (Structure of the cooling system)

[0036] like Figure 1 As shown, the cooling system S has a refrigerant flow device 10, a pressure reducing device 20, and a controller 30.

[0037] The refrigerant flow device 10 has a refrigerant flow path 11 for facilitating refrigerant flow. The refrigerant flow path 11 includes an upstream end 11U and a downstream end 11D. The pressure reducing device 20 includes an inlet 20A and an outlet 20B. The inlet 20A is connected to the downstream end 11D of the refrigerant flow path 11 to draw gas from the refrigerant flow path 11, and the outlet 20B is connected to the upstream end 11U of the refrigerant flow path 11 to allow gas drawn from the inlet 20A to flow into the refrigerant flow path 11 from the upstream end 11U.

[0038] The refrigerant flow device 10 includes, from upstream to downstream, a storage tank 12, a dryer 13, a control valve 14, a double-laminar flow separator 15, a temperature control unit 16, a gas-liquid separator 17, and a butterfly valve 18, all arranged in the refrigerant flow path 11. That is, the refrigerant flow path 11 is constructed by sequentially connecting the storage tank 12, dryer 13, control valve 14, double-laminar flow separator 15, temperature control unit 16, gas-liquid separator 17, and butterfly valve 18 using piping components.

[0039] When the cooling system S is operating, the control valve 14 in the refrigerant flow path 11 is controlled to a state where its opening is reduced. In this state, the pressure reducing device 20 draws in gas present in the refrigerant flow path 11 or gas vaporized in the refrigerant flow path 11 from the downstream end 11D of the refrigerant flow path 11. Thus, the pressure reducing device 20 reduces or maintains the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14.

[0040] As described above, by drawing gas from the refrigerant flow path 11 through the pressure reducing device 20, the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14 is reduced to a pressure lower than atmospheric pressure. On the other hand, the internal pressure of the portion of the refrigerant flow path 11 upstream of the control valve 14 is set to a pressure greater than the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14, such as atmospheric pressure.

[0041] The gas drawn from the downstream end 11D of the refrigerant flow path 11 by the pressure reducing device 20 flows into the interior of the refrigerant flow path 11 from the upstream end 11U. The refrigerant flow device 10 allows the refrigerant contained in the gas flowing in from the pressure reducing device 20 to flow through the refrigerant flow path 11. Furthermore, the refrigerant flow device 10 liquefies the refrigerant as much as possible before it reaches the control valve 14 in the refrigerant flow path 11. Moreover, the liquefied refrigerant is depressurized and cooled as it flows into the portion of the refrigerant flow path 11 downstream of the control valve 14. Thus, the temperature control section 16, located downstream of the control valve 14 in the refrigerant flow path 11, allows the flow of low-temperature refrigerant. Furthermore, by exchanging heat between the refrigerant and the temperature-controlled object in the temperature control section 16, the temperature-controlled object can be cooled using the refrigerant.

[0042] The refrigerant that exchanges heat with the temperature-controlled object in the temperature control unit 16 can evaporate by absorbing heat from the temperature-controlled object. In this case, the refrigerant can efficiently cool the temperature-controlled object using its latent heat of vaporization. Moreover, the evaporated refrigerant is in a gaseous state and is drawn in by the pressure reducing device 20. Here, the gaseous refrigerant drawn in by the pressure reducing device 20 absorbs heat from the temperature-controlled object. In this embodiment, the heat absorbed by the refrigerant is mainly released to the outside through the storage tank 12 in the refrigerant flow path 11. As a result, the temperature-controlled object can be continuously cooled.

[0043] The refrigerant circulated in the cooling system S is not particularly limited. For example, it can be a substance that is liquid at atmospheric pressure and standard ambient temperature (e.g., 25°C), and expands to below -5°C when it reaches a pressure of, for example, 0.1 atmospheres. Preferably, it is a substance that expands to below -30°C when it reaches a pressure of 0.01 atmospheres. Using such a substance as a refrigerant allows for cooling to low-temperature regions. Furthermore, in this specification, atmospheric pressure refers to one atmosphere, or 0.1 MPa (Abs).

[0044] The refrigerant flow device 10 and pressure reducing device 20 constituting the cooling system S will be described in detail below.

[0045] The storage tank 12 in the refrigerant flow device 10 stores the refrigerant, which has become liquid in the gas phase, flowing from the pressure reducing device 20 into the refrigerant flow path 11. As described above, the internal pressure of the portion of the refrigerant flow path 11 upstream of the control valve 14 is greater than the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14. Therefore, the gas flowing into the refrigerant flow path 11 from the pressure reducing device 20 is pressurized and heated. At this time, the refrigerant contained in the gas is also pressurized and heated from the gaseous phase, and is about to liquefy.

[0046] The refrigerant contained in the gas flowing in from the pressure reducing device 20 can become a liquid phase at least partially before reaching the storage tank 12. The storage tank 12 can store the refrigerant that naturally becomes a liquid phase. However, there are cases where it is difficult to liquefy all the gaseous refrigerant flowing in from the pressure reducing device 20 before reaching the storage tank 12. Therefore, the storage tank 12 in this embodiment has a cooler 12A for cooling and liquefying the gaseous refrigerant. The cooler 12A is provided inside the storage tank 12 and mainly cools the gas flowing from the pressure reducing device 20 into the storage tank 12. As a result, most of the refrigerant in the gas flowing in from the pressure reducing device 20 can be liquefied in the storage tank 12 and the liquid phase refrigerant can be stored. Alternatively, the cooler 12A can also be provided outside the storage tank 12, for example, it can be a structure that cools the upstream portion of the storage tank 12 in the refrigerant flow path 11.

[0047] The storage tank 12 has a gas inlet 12i at its upper part and a discharge outlet 12e at its bottom for liquid refrigerant to flow downstream. Specifically, the storage tank 12 includes a container body 12B with an opening and a cover 12C for opening and closing. The inlet 12i is located at the upper part of the container body 12B, and the discharge outlet 12e is located at the bottom of the container body 12B. The positions of the inlet 12i and the discharge outlet 12e are not particularly limited. Furthermore, by keeping the cover 12C open, for example, pressure rise in the storage tank 12 can be prevented, thus suppressing the power consumption of the pressure reducing device 20. Additionally, by keeping the cover 12C open, refrigerant can be filled or replenished.

[0048] The dryer 13 adsorbs moisture and foreign matter contained in the liquid phase of the refrigerant from the storage tank 12. The dryer 13 can be constructed, for example, by containing a porous material in the adsorption tank (container section). In this case, the porous material can be a molecular sieve, activated alumina, or a mixture thereof.

[0049] Control valve 14 controls the flow of refrigerant into the dryer 13. Specifically, control valve 14 controls the flow of primarily liquid refrigerant into the dryer 13. During operation of the cooling system S, control valve 14 reduces its opening at the same time as the suction action of the pressure reducing device 20 begins, thus restricting the flow of refrigerant and controlling the downstream portion of control valve 14 in the refrigerant flow path 11 to a desired pressure-reducing state. Furthermore, control valve 14 regulates the flow rate of refrigerant flowing downstream from control valve 14, thereby enabling, for example, adjustment of the temperature or cooling capacity of the refrigerant flowing in the temperature control unit 16.

[0050] Furthermore, as described above, the internal pressure of the portion of the refrigerant flow path 11 upstream of the control valve 14 is greater than the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14. Therefore, the refrigerant passing through the control valve 14 is depressurized and cooled as it flows into the portion of the refrigerant flow path 11 downstream of the control valve 14. In other words, the refrigerant passing through the control valve 14 expands and cools as it flows into the portion of the refrigerant flow path 11 downstream of the control valve 14. Therefore, the control valve 14 also functions like an expansion valve in a refrigeration circuit, causing the liquid refrigerant to expand.

[0051] The refrigerant flowing out of control valve 14 can partially vaporize through expansion. Therefore, the refrigerant flowing out of control valve 14 sometimes flows downstream in a gas-liquid mixed state. However, the refrigerant flowing out of control valve 14 sometimes flows downstream while remaining in a liquid state. In either case, the refrigerant is depressurized (expanded), and therefore its temperature decreases. The form of control valve 14 is not particularly limited, but in this embodiment it is an electrically operated proportional control valve. Control valve 14 is electrically connected to controller 30. Control valve 14 is controlled by controller 30.

[0052] The dual-layer flow separator 15 includes an inlet 15A and an outlet 15B. The inlet 15A allows refrigerant from the control valve 14 to flow in, and the outlet 15B is located below the inlet 15A, allowing the refrigerant flowing in from the inlet 15A to flow out. In the downstream portion of the refrigerant flow path 11, the temperature of the refrigerant in the downstream region is generally lower than the temperature of the refrigerant in the upstream region. Moreover, the temperature of the refrigerant just flowing out of the control valve 14 is generally higher than the temperature of the refrigerant already present in its downstream region. In addition, the refrigerant just flowing out of the control valve 14 flows rapidly downstream in a drawn-down manner. Therefore, the dual-layer flow separator 15 is provided to suppress the rapid downstream flow of the higher-temperature phase in the refrigerant flowing out of the control valve 14.

[0053] That is, in the double-layer flow separator 15, the inlet 15A is provided above the outlet 15B, so that the higher-temperature phase of the refrigerant is less likely to flow in a straight line towards the outlet 15B. Furthermore, the higher-temperature phase of the refrigerant tends to flow upwards relative to the lower-temperature phase, thus preventing it from flowing in a straight line towards the outlet 15B. As described above, the double-layer flow separator 15 suppresses the situation where the higher-temperature phase of the refrigerant flowing into the double-layer flow separator 15 flows in a straight line towards the outlet 15B, thereby suppressing the situation where the higher-temperature phase flows rapidly downstream.

[0054] In detail, the double-layer flow separator 15 has a container body 15C, which defines its internal space by forming a flow path cross-sectional area larger than that of the piping component connecting the inlet 15A and the control valve 14. The inlet 15A is provided on the upper part of the side wall of the container body 15C (the portion of the side wall slightly above the center in the vertical direction), and the outlet 15B is provided on the bottom wall of the container body 15C. Furthermore, in this embodiment, the inlet 15A and the outlet 15B do not overlap in the horizontal direction. Moreover, the inlet 15A and the outlet 15B are significantly separated in the vertical direction. With this structure, the higher-temperature phase of the refrigerant flowing from the control valve 14 is less likely to reach the outlet 15B. The positions of the inlet 15A and the outlet 15B are not particularly limited. Furthermore, the state that the inlet 15A and the outlet 15B do not overlap in the horizontal direction means that when the inlet 15A is projected towards the outlet 15B in the horizontal direction, the two do not overlap at all. However, the formation locations of inlet 15A and outlet 15B are not limited to this method.

[0055] exist Figure 1 In the diagram, the interior of the double-layer flow separator 15 is shown using color differentiation. This indicates that the temperature of the refrigerant portion represented by the darker color (the lower portion in the diagram) is lower than the temperature of the refrigerant portion represented by the lighter color (the upper portion in the diagram).

[0056] The temperature control unit 16 circulates the refrigerant flowing from the double-layer flow separator 15 and cools the temperature-controlled object (not shown) through the refrigerant. The temperature control unit 16 can be formed in, for example, a meandering shape, a spiral shape, or a curved shape. The structure of the temperature control unit 16 is not particularly limited; the temperature control unit 16 can be composed of, for example, a finned tube heat exchanger, or it can include a plate-shaped heat conductor.

[0057] The gas-liquid separator 17 allows refrigerant passing through the temperature control unit 16 to flow in, separating the refrigerant into a gaseous phase and a liquid phase. Specifically, the gas-liquid separator 17 separates the gaseous and liquid phases of the refrigerant passing through the temperature control unit 16 such that the gaseous phase flows downstream of the liquid phase. When the temperature control unit 16 exchanges heat with the temperature-controlled object, a portion of the refrigerant may evaporate and vaporize. Therefore, the refrigerant flowing from the temperature control unit 16 towards the gas-liquid separator 17 may contain both a gaseous and a liquid phase. The gas-liquid separator 17 functions to separate the gaseous and liquid phases of the refrigerant passing through the temperature control unit 16 and to allow the gaseous refrigerant to flow upwards.

[0058] The gas-liquid separator 17 includes an inlet 17A and an outlet 17B. The inlet 17A allows refrigerant from the temperature control unit 16 to flow in, and the outlet 17B is located above the inlet 17A to allow the refrigerant flowing in from the inlet 17A to flow out. Specifically, the gas-liquid separator 17 has a container body 17C, whose internal space is defined by forming a flow path cross-sectional area larger than that of the piping connecting the inlet 17A and the temperature control unit 16. The inlet 17A is located on the bottom wall of the container body 17C, and the outlet 17B is located on the top wall of the container body 17C. The positions of the inlet 17A and the outlet 17B are not particularly limited, but it is preferable that the inlet 17A and the outlet 17B are significantly separated vertically. In this case, the gas phase flows upwards compared to the liquid phase, so the gas phase portion of the refrigerant flowing downstream in the gas-liquid separator 17 is easily discharged downstream through the outlet 17B. In addition, the situation where the liquid refrigerant is drawn away by the pressure reducing device 20 is suppressed.

[0059] Inside the gas-liquid separator 17, the liquid phase is represented by a darker color, and the gas phase is represented above it. In the gas-liquid separator 17, it is preferable to introduce the liquid refrigerant in such a way that a gas phase is always formed at the top. The environment in the gas-liquid separator 17 where the liquid refrigerant and the gas phase coexist can be created by controlling the operation of the pressure reducing device 20, control valve 14, etc. The gas-liquid separator 17 is configured to maintain its shape when the internal pressure is reduced, and can also be constructed as a so-called vacuum insulated container. The maintenance of the shape of the gas-liquid separator 17 during pressure reduction also depends on the internal pressure being reduced, but for example, when the pressure is reduced to 0.1 atmospheres, the outer shell of the gas-liquid separator 17 is preferably made of a thick, hard metal or the like. However, the specific construction of the gas-liquid separator 17 is not particularly limited, as long as it is appropriately determined according to the predetermined degree of pressure reduction.

[0060] Furthermore, in this embodiment, the gas-liquid separator 17 and the storage tank 12 are arranged at the same or approximately the same position in the vertical direction. Therefore, in this embodiment, when operation is stopped, the refrigerant flows in such a manner that the liquid level of the refrigerant in the gas-liquid separator 17 is the same as the liquid level of the refrigerant in the storage tank 12. By pre-establishing this state, the next operation can begin smoothly.

[0061] Butterfly valve 18 is a valve that controls the amount of gas drawn into the refrigerant flow path 11 by the pressure reducing device 20. Butterfly valve 18 can also be configured to have its opening controlled by an electric motor. Butterfly valve 18 is electrically connected to controller 30. Butterfly valve 18 is controlled by controller 30.

[0062] Furthermore, in this embodiment, the portion between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11 and the downstream portion of the temperature control unit 16 in the refrigerant flow path 11 constitute an internal heat exchanger 19. This internal heat exchanger 19 enables the refrigerant flowing in these two portions to exchange heat with each other. Specifically, the portion between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11 is the downstream side of the control valve 14 and the upstream side of the double-layer flow separator 15, which is the upstream side of the temperature control unit 16. Specifically, in this embodiment, the downstream portion of the temperature control unit 16 in the refrigerant flow path 11 is the portion between the temperature control unit 16 and the gas-liquid separator 17. By constructing such an internal heat exchanger 19, the refrigerant flowing in the portion between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11 can be cooled. The refrigerant flowing between the temperature control unit 16 and the gas-liquid separator 17 in the refrigerant flow path 11 can be heated.

[0063] In addition, the refrigerant flow device 10 includes a first temperature sensor 101, a second temperature sensor 102, a third temperature sensor 103, a first pressure sensor 104, a second pressure sensor 105, a first liquid level sensor 106, and a second liquid level sensor 107.

[0064] The first temperature sensor 101 detects the temperature of the refrigerant flowing in the temperature control unit 16. The second temperature sensor 102 detects the temperature of the refrigerant flowing between the double-laminar separator 15 and the temperature control unit 16 in the refrigerant flow path 11. The third temperature sensor 103 detects the temperature of the refrigerant flowing between the temperature control unit 16 and the gas-liquid separator 17 in the refrigerant flow path 11 (the portion upstream of the internal heat exchanger 19). The first pressure sensor 104 detects the pressure of the refrigerant flowing between the double-laminar separator 15 and the temperature control unit 16 in the refrigerant flow path 11. The second pressure sensor 105 detects the pressure of the refrigerant flowing between the temperature control unit 16 and the gas-liquid separator 17 in the refrigerant flow path 11 (the portion upstream of the internal heat exchanger 19).

[0065] The first liquid level sensor 106 detects the height of the refrigerant in the liquid phase stored in the storage tank 12. The second liquid level sensor 107 detects the height of the refrigerant in the liquid phase stored in the gas-liquid separator 17. The first liquid level sensor 106 and the second liquid level sensor 107 can be optical sensors, such as laser displacement meters, in which case light is shone onto the liquid surface from above and the reflected light is received to calculate the liquid level height. However, the first liquid level sensor 106 and the second liquid level sensor 107 can also be float-type sensors.

[0066] Each sensor (101-107) is electrically connected to the controller 30, and the detection results of each sensor are sent to the controller 30.

[0067] The pressure reducing device 20 includes a gas suction pump 22 that draws gas from the refrigerant flow path 11. The gas suction pump 22 draws gas from the refrigerant flow path 11 through an inlet 20A connected to the downstream end 11D of the refrigerant flow path 11, and allows the gas drawn from the inlet 20A to flow into the refrigerant flow path 11 through an outlet 20B connected to the upstream end 11U of the refrigerant flow path 11. The inlet 20A and outlet 20B can be formed in the gas suction pump 22 or in the piping section connected to the gas suction pump 22.

[0068] The form of the gas suction pump 22 is not particularly limited, but it is preferably a dry vacuum pump in which lubricating oil does not flow out or substantially does not flow out to the suction path side. The dry vacuum pump can be a diaphragm dry vacuum pump, a swing piston dry vacuum pump, a rotary vane dry vacuum pump, a scroll dry vacuum pump, etc., or may differ from the examples shown above. However, the gas suction pump 22 can also be a wet vacuum pump.

[0069] The gas suction pump 22 in this embodiment is a dry vacuum pump. Furthermore, the gas suction pump 22 includes, for example, an AC motor, a brushless DC motor, or a motor controlled by an inverter. Moreover, by adjusting the motor speed, the gas suction pump 22 can regulate the gas suction volume, thereby adjusting the internal pressure of the portion of the refrigerant flow path 11 downstream of the control valve 14.

[0070] The gas suction pump 22 is electrically connected to and controlled by the controller 30. In this embodiment, the gas suction pump 22 is electrically connected to the controller 30 via the inverter 40. Specifically, the speed of the motor is adjusted by the controller 30 using the frequency of the alternating current supplied to the motor by the inverter 40.

[0071] The controller 30 is electrically connected to the aforementioned sensors (101-107), and also electrically connected to the control valve 14, butterfly valve 18, and gas suction pump 22. The controller 30 may also be configured as a computer with a CPU, ROM, etc. In this case, the controller 30 performs various processes according to the program stored in the ROM. Alternatively, the controller 30 may be configured with other processors or circuits (e.g., FPGA (Field Programmable Gate Array)).

[0072] (Functional structure of the controller)

[0073] Figure 2 This is a block diagram illustrating the functional structure of the controller 30. (Example) Figure 2 As shown, the controller 30 includes a sensor information acquisition unit 31, a speed regulation unit 32, and a valve opening regulation unit 33. Furthermore, the controller 30 can be configured as a single computer or multiple computers. In the case of multiple computers, the aforementioned functional units can be distributed among the computers.

[0074] The sensor information acquisition unit 31 acquires the detection results from the first temperature sensor 101, the second temperature sensor 102, the third temperature sensor 103, the first pressure sensor 104, the second pressure sensor 105, the first liquid level sensor 106, and the second liquid level sensor 107. The sensor information acquisition unit 31 provides one or more pieces of information related to the acquired detection results to the speed regulation unit 32 and the valve opening regulation unit 33.

[0075] The speed regulating unit 32 is electrically connected to the gas suction pump 22 and is the part that controls the operation of the gas suction pump 22. Specifically, the speed regulating unit 32 is connected to the motor in the gas suction pump 22 via the inverter 40. Moreover, the speed regulating unit 32 regulates the flow rate of the gas drawn from the refrigerant flow path 11 by the pressure reducing device 20 by adjusting the frequency of the alternating current supplied from the inverter 40 to the motor.

[0076] In the speed regulation unit 32, for example, a target temperature of the refrigerant in or before it flows into the temperature control unit 16 is input and maintained via an input device (not shown). The speed regulation unit 32 adjusts the speed of the motor of the gas suction pump 22, for example, in a manner that makes the temperature detected by the first temperature sensor 101 or the second temperature sensor 102 match the target temperature. That is, the gas suction pump 22 can also be controlled based on the difference between the temperature of the refrigerant and the target temperature, i.e., the detection result from the first temperature sensor 101 or the second temperature sensor 102.

[0077] In addition, in the control example described above, the gas suction pump 22 of the pressure reducing device 20 is controlled in a way that makes the temperature of the refrigerant consistent with the target temperature. However, it is also possible to adjust the speed of the motor in a way that makes the pressure of the refrigerant in the refrigerant flow path 11 consistent with the target value instead.

[0078] The valve opening adjustment unit 33 is electrically connected to the control valve 14 and the butterfly valve 18, and is the part that controls the operation of the control valve 14 and the butterfly valve 18. The valve opening adjustment unit 33 adjusts the flow rate of refrigerant flowing in the refrigerant flow path 11 by adjusting the opening of the control valve 14. In addition, the valve opening adjustment unit 33 adjusts the intake amount of gas drawn by the pressure reducing device 20 by adjusting the opening of the butterfly valve 18.

[0079] In the valve opening adjustment unit 33, for example via an input device not shown, a target temperature of the refrigerant in or before it flows into the temperature control unit 16 is input and maintained. This is achieved, for example, by adjusting the opening of the control valve 14 or the butterfly valve 18 in a manner that makes the temperature detected by the first temperature sensor 101 or the second temperature sensor 102 match the target temperature. Such control of the opening of the control valve 14 or the butterfly valve 18 can also be performed after the gas suction pump 22 is controlled in a manner that makes the refrigerant temperature match the target temperature and the operating state of the gas suction pump 22 is maintained at a constant level.

[0080] (Structure of refrigerant)

[0081] Next, the refrigerant circulating in the cooling system S will be described. As described above, in this embodiment, the refrigerant is, for example, a substance that is liquid at atmospheric pressure and a standard ambient temperature (e.g., 25°C) and expands to -5°C or lower at a pressure of, for example, 0.1 atmospheres, preferably a substance that expands to -30°C or lower at a pressure of 0.01 atmospheres. Furthermore, the refrigerant is preferably a low-environmental-load refrigerant with a Global Warming Potential (GWP) of 10 or lower. In the case of a substance with a boiling point of 30°C or higher at atmospheric pressure, this substance is liquid at atmospheric pressure and a standard ambient temperature (e.g., 25°C). Additionally, the boiling point of the refrigerant used at atmospheric pressure can be 50°C or higher, 60°C or higher, or 70°C or higher.

[0082] Specifically, in this embodiment, HFO-1336mzz-Z, which has a GWP of 2 and is non-flammable, is preferably used as the refrigerant. More specifically, the refrigerant can be OpteonSF33(TM) manufactured by Chemours-Mitsui Fluoroproducts Co., Ltd.

[0083] Figure 3 This is the pH graph of HFO-1336mzz-Z. HFO-1336mzz-Z is depressurized from approximately 0.100 MPa near atmospheric pressure and approximately 33°C (close to room temperature) (St1) to 0.0149 MPa, thereby cooling to approximately -10°C (St2). Furthermore, by depressurizing to 0.001 MPa, it cools to below approximately -50°C. Then, if it absorbs heat to some extent from state St2 (approximately -10°C), it will evaporate (St3). If it moves from state St3 to approximately 0.100 MPa near atmospheric pressure, it heats up to approximately 50°C above room temperature while remaining in a gaseous phase (St4). Then, by cooling from state St4 at room temperature, it condenses into a gas-liquid mixture and cools to approximately 33°C.

[0084] Such HFO-1336mzz-Z is cooled, for example, by the cooler 12A in the storage tank 12 and transferred to the aforementioned state St1. Then, by flowing out from the control valve 14, it is depressurized and can be transferred to state St2, for example. Then, HFO-1336mzz-Z can be transferred from state St2 to state St3 by exchanging heat with the temperature-controlled object in the temperature control unit 16. After that, by flowing out from the gas-liquid separator 17 to the outside of the pressure reducing device 20, it can be transferred from state St3 to state St4. Therefore, HFO-1336mzz-Z can be appropriately used in the cooling system S.

[0085] Other types of refrigerants that can be used in the cooling system S include water and ethanol.

[0086] (action)

[0087] The following is an example of the operation of the cooling system S.

[0088] First, in the cooling system S, refrigerant at the desired flow rate arrives at the gas-liquid separator 17 from the storage tank 12 in the refrigerant flow path 11 and is stored. Then, for example, the target temperature of the refrigerant flowing through the temperature control unit 16 is input and maintained. Next, the pressure reducing device 20 is driven to reduce the internal pressure of the downstream portion of the control valve 14 in the refrigerant flow path 11 to a pressure lower than atmospheric pressure. At this time, the control valve 14 can be closed or reduced to a smaller opening. Then, the pressure reducing device 20 adjusts the speed of the motor of the gas suction pump 22 until the temperature detected by the first temperature sensor 101 matches the target temperature.

[0089] After the temperature detected by the first temperature sensor 101 matches the target temperature, at least one of the following is controlled to maintain the target temperature: the speed of the gas suction pump 22 motor, the opening of the control valve 14, and the opening of the butterfly valve 18. This completes the startup process. After adjusting the speed of the gas suction pump 22 motor to match the temperature detected by the first temperature sensor 101 with the target temperature, the pressure reduction device 20 reduces the internal pressure in the portion of the refrigerant flow path 11 downstream of the control valve 14 to a pressure lower than atmospheric pressure. The pressure in the portion of the refrigerant flow path 11 upstream of the control valve 14 is set to a pressure higher than the internal pressure in the downstream portion, for example, set to atmospheric pressure. However, the pressure in the portion of the refrigerant flow path 11 upstream of the control valve 14 may not be strictly atmospheric pressure, but may be a pressure slightly lower than atmospheric pressure.

[0090] Then, the process transitions to a state where the temperature-controlled object is cooled by the temperature control unit 16. After heat exchange by the temperature control unit 16, the refrigerant is drawn back into the refrigerant flow path 11 from the upstream end 11U by the pressure reducing device 20. After being cooled until it reaches the control valve 14, it flows back into the temperature control unit 16 through the control valve 14. Thus, the temperature-controlled object is continuously cooled by the refrigerant.

[0091] That is, when using Figure 3When describing the operating state of the cooling system S, the refrigerant, having absorbed heat from the temperature-controlled object by the temperature control unit 16, flows from the downstream end 11D of the refrigerant flow path 11 to the upstream end 11U of the refrigerant flow path 11 via the pressure reducing device 20, and is cooled by the cooler 12A, etc., until it reaches the control valve 14. Figure 3 The refrigerant transitions from state St4 to state St1. Then, refrigerant flows out from control valve 14, thereby reducing pressure in the downstream portion of control valve 14 in the refrigerant flow path 11 and transitioning to state St2. Next, the refrigerant exchanges heat with the temperature-controlled object in the temperature control unit 16, thereby transitioning from state St2 to state St3. Then, refrigerant flows from pressure reducing device 20 into the upstream portion of control valve 14 in the refrigerant flow path 11, thereby transitioning from state St3 to state St4. The refrigerant is then cooled until it reaches control valve 14, transitioning from state St4 to state St1. Thus, the temperature-controlled object is continuously cooled by the refrigerant.

[0092] The cooling system S of the first embodiment described above includes: a refrigerant flow device 10, which includes a refrigerant flow path 11 and a control valve 14. The refrigerant flow path 11 allows refrigerant to flow, and the control valve 14 is provided in the refrigerant flow path 11 to control the flow of refrigerant; and a pressure reducing device 20, which includes an inlet 20A and an outlet 20B. The inlet 20A is connected to the downstream end 11D of the refrigerant flow path 11 to draw gas from the refrigerant flow path 11, and the outlet 20B is connected to the upstream end 11U of the refrigerant flow path 11, so that the gas drawn from the inlet 20A flows into the refrigerant flow path 11 from the upstream end 11U. The refrigerant flow path 11 allows the refrigerant contained in the gas flowing in from the pressure reducing device 20 to flow. Furthermore, the refrigerant flow device 10 has a temperature control unit 16 downstream of the control valve 14 in the refrigerant flow path 11, which uses refrigerant to cool the temperature-controlled object.

[0093] According to such a cooling system S, substances that have not been used in previous refrigeration methods can be used as refrigerants for the thermal cycle, or the range of substances that can be used as refrigerants for the thermal cycle can be expanded.

[0094] That is, as described above, although this is only one example in this embodiment, substances that are liquid at atmospheric pressure and standard ambient temperature (e.g., 25°C) and expand to below -5°C at a pressure of 0.1 atmospheres from that state can be used as refrigerants. In contrast, if the above-mentioned substance is used in the vapor compression refrigeration cycle that is popular to date, the compressor will compress the liquid, and therefore the compressor will not function properly, and the substance will not evaporate in the evaporator. Therefore, the above-mentioned refrigerant is not suitable for vapor compression refrigeration cycles. In contrast, the cooling system S does not utilize compression. By depressurizing the refrigerant in the downstream portion of the control valve 14 in the refrigerant flow path 11, the temperature-controlled object can be cooled, and the heat of the temperature-controlled object can be released from the upstream portion of the control valve 14 in the refrigerant flow path 11, thus achieving a thermal cycle. Therefore, according to this embodiment, substances that have not been used in conventional refrigeration methods can be used as refrigerants for thermal cycles, or the range of substances that can be used as refrigerants for thermal cycles can be expanded.

[0095] Furthermore, as mentioned above, the cooling system S can use refrigerants such as HFO-1336mzz-Z, which has a GWP of 2 and is non-flammable. Therefore, in a vapor compression refrigeration cycle, it is possible to achieve cooling operations with a low GWP that are currently impossible to achieve while ensuring safety. Such a low-GWP, environmentally friendly, and safe cooling system S, including other cooling methods, is unknown. Therefore, the realization of such a cooling system S has the potential to make a significant contribution to environmental protection. Additionally, since a compressor is not used in the cooling system S, the leakage of lubricating oil to the refrigerant side is suppressed, which is also advantageous.

[0096] Furthermore, the cooling system S has a gas-liquid separator 17 downstream of the temperature control section 16 in the refrigerant flow path 11. This gas-liquid separator 17 separates the gas phase from the liquid phase in a manner that causes the gas phase portion of the refrigerant passing through the temperature control section 16 to flow downstream more than the liquid phase portion. In this configuration, the situation where liquid refrigerant is drawn from the downstream end 11D of the refrigerant flow path 11 by the pressure reducing device 20 is suppressed. As a result, the pressure reducing device 20 can operate in a stable state, thereby improving the operational stability of the cooling system S.

[0097] Furthermore, the refrigerant flow device 10 has a storage tank 12 upstream of the control valve 14 in the refrigerant flow path 11. This storage tank 12 stores the refrigerant obtained by the gas flowing from the pressure reducing device 20 into the refrigerant flow path 11 turning into a liquid phase. Moreover, the control valve 14 controls the flow of the liquid refrigerant flowing from the storage tank 12. In this configuration, the flow of the hotter gaseous refrigerant from the pressure reducing device 20 into the refrigerant flow path 11 downstream of the control valve 14 in the refrigerant flow path 11 is suppressed. Therefore, desired cooling can be achieved in the temperature control unit 16.

[0098] Furthermore, the refrigerant flow device 10 has a double-laminar flow separator 15 between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11. The double-laminar flow separator 15 includes an inlet 15A and an outlet 15B. The inlet 15A allows refrigerant from the control valve 14 to flow in, and the outlet 15B is located below the inlet 15A, allowing the refrigerant flowing in from the inlet 15A to flow out. In this structure, the situation where the higher-temperature phase of the refrigerant flowing into the double-laminar flow separator 15 flows rapidly downstream is suppressed. As a result, desired cooling can be achieved in the temperature control unit 16.

[0099] Furthermore, in this embodiment, the portion between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11, and the downstream portion of the temperature control unit 16 in the refrigerant flow path 11, constitute an internal heat exchanger 19. This internal heat exchanger 19 enables the refrigerants flowing in these two portions to exchange heat with each other. In this structure, the refrigerant flowing in the portion between the control valve 14 and the temperature control unit 16 in the refrigerant flow path 11 can be cooled. The refrigerant flowing in the portion between the temperature control unit 16 and the gas-liquid separator 17 in the refrigerant flow path 11 can be heated. As a result, the refrigerant flowing into the temperature control unit 16 is further cooled, and the refrigerant flowing into the gas-liquid separator 17 is easily vaporized. Therefore, the cooling system S can be operated in the desired state.

[0100] <Application Examples>

[0101] The following is for reference Figures 4 to 7 An application example of the cooling system S according to the above-described embodiment will be described. Unless otherwise specified, the cooling system S in the application examples described below has the same structural elements as in the above-described embodiment.

[0102] (Application Example 1)

[0103] Figure 4This is a schematic diagram of a plasma etching apparatus 200 with a cooling system S. The plasma etching apparatus 200 includes an electrostatic chuck 201. The electrostatic chuck 201 has a plate-shaped substrate 202, on which the wafer W is adsorbed and held. Furthermore, the substrate 202 is connected to the temperature control unit 16 of the cooling system S through the interior of the substrate 202. The temperature control unit 16 cools the substrate 202 and the wafer W by absorbing heat from the substrate 202. In this example, a first temperature sensor 101 configured as part of the cooling system S detects the temperature of the substrate 202. Additionally, a heater 203 is built into the substrate 202. In the plasma etching apparatus 200, the wafer W can be cooled and heated. Furthermore, in… Figure 4 In the cooling system S, a fan 120 is provided to cool the upstream portion of the storage tank 12 in the refrigerant flow path 11. This promotes the liquefaction of the refrigerant flowing from the pressure reducing device 20 into the refrigerant flow path 11. Such a fan 120 can also be used in the cooling system S described in the above-described embodiments and the following application examples.

[0104] (Application Example 2)

[0105] Figure 5 This is a schematic diagram of a cooking appliance 210 having a cooling system S. The cooking appliance 210 is a so-called cooling plate, having a cooking plate 211 cooled by a temperature control unit 16 of the cooling system S. The temperature control unit 16 is connected to the cooking plate 211 in a state of passing through the interior of the cooking plate 211. In this example, a first temperature sensor 101 configured as the cooling system S detects the temperature of the cooking plate 211.

[0106] (Application Example 3)

[0107] Figure 6 This is a schematic diagram of a molding apparatus 220 equipped with a cooling system S. The molding apparatus 220 has a mold 221 cooled by a temperature control unit 16 of the cooling system S. The temperature control unit 16 is connected to the mold 221 in a state where it passes through the interior of the mold 221. In this example, a first temperature sensor 101 configured as part of the cooling system S detects the temperature of the mold 221.

[0108] (Application Example 4)

[0109] Figure 7This is a schematic diagram of a cold storage warehouse 230 equipped with a cooling system S. The cold storage warehouse 230 has a warehouse body 231 and a pipe 232 connected to the warehouse body 231. The pipe 232 is connected to the warehouse body 231 at both ends, introducing gas from the warehouse body 231 at one end and allowing the introduced gas to flow into the warehouse body 231 from the other end. A fan 233 is arranged in the pipe 232, and a temperature control unit 16 of the cooling system S is also arranged therein. Gas is introduced from the warehouse body 231 by the rotation of the fan 233, and this gas is cooled by the temperature control unit 16. Thus, the cooled gas flows into the warehouse body 231 from the pipe 232. Furthermore, in... Figure 7 In the example shown, a first temperature sensor 101 for detecting the temperature of the temperature control unit 16 is not provided, but a first temperature sensor 101 may also be provided.

[0110] The embodiments of the present invention have been described above, but the present invention is not limited to the embodiments described above, and various further modifications can be made to the above embodiments. Furthermore, the cooling system S can be used for various purposes other than the application examples described above.

[0111] The following is for reference Figure 8 The modified cooling system Sv will be described. In this cooling system Sv, the temperature control unit 16 is integrated with the gas-liquid separator 17, and the temperature control unit 16 is not located between the control valve 14 and the double-laminar flow separator 15 as in the embodiment described above. The gas-liquid separator 17 is configured to cool the temperature-controlled object using the liquid phase refrigerant inside it. Figure 8 In this example, the temperature control object is the hot medium flowing in the hot medium piping assembly 240. The hot medium piping assembly 240 is connected to the gas-liquid separator 17 via the interior of the gas-liquid separator 17.

[0112] Furthermore, the cooling system Sv includes the same dryer 13, control valve 14, double-laminar flow separator 15, temperature control unit 16, gas-liquid separator 17, butterfly valve 18, and internal heat exchanger 19 as in the embodiment described above. These components are identical to those in the embodiment described above. Additionally, in the cooling system Sv, the object being cooled is cooled using the liquid phase refrigerant inside the gas-liquid separator 17, but cooling can also be performed using the gas phase refrigerant. Furthermore, the cooling system Sv can also be configured to cool the outer surface of the gas-liquid separator 17.

Claims

1. A cooling system comprising: A refrigerant flow device includes a refrigerant flow path and a control valve, the refrigerant flow path allowing refrigerant to flow, and the control valve being disposed in the refrigerant flow path to control the flow of the refrigerant; and A pressure reducing device includes an inlet and an outlet. The inlet is connected to the downstream end of the refrigerant flow path to draw gas from the refrigerant flow path. The outlet is connected to the upstream end of the refrigerant flow path to allow the gas drawn from the inlet to flow into the refrigerant flow path from the upstream end. The refrigerant flow path allows the refrigerant contained in the gas flowing in from the pressure reducing device to circulate. The refrigerant flow device has a temperature control unit downstream of the control valve in the refrigerant flow path, which uses the refrigerant to cool the object under temperature control.

2. The cooling system according to claim 1, wherein, The refrigerant flow device has a gas-liquid separator downstream of the temperature control section in the refrigerant flow path. The gas-liquid separator separates the gas phase portion from the liquid phase portion of the refrigerant in such a way that the gas phase portion of the refrigerant that has passed through the temperature control section flows downstream in a manner that makes the liquid phase portion flow more downstream than the gas phase portion.

3. The cooling system according to claim 1, wherein, The refrigerant flow device has a storage tank upstream of the control valve in the refrigerant flow path. This storage tank stores the refrigerant, in its liquid phase, which flows from the pressure reducing device into the refrigerant flow path. The control valve controls the flow of the liquid refrigerant into the storage tank.

4. The cooling system according to claim 3, wherein, The storage tank has a cooler that cools the gas flowing in from the pressure reducing device, causing the refrigerant to liquefy from the gas.

5. The cooling system according to claim 1, wherein, The refrigerant flow device has a double-laminar flow separator between the control valve and the temperature control unit in the refrigerant flow path. The dual-layer flow separator includes an inlet and an outlet. The inlet allows the refrigerant from the control valve to flow in, and the outlet is located below the inlet to allow the refrigerant flowing in from the inlet to flow out.

6. The cooling system according to claim 1, wherein, The portion between the control valve and the temperature control unit in the refrigerant flow path and the downstream portion of the temperature control unit in the refrigerant flow path constitute an internal heat exchanger, which enables the refrigerant flowing in these two portions to exchange heat with each other.

7. The cooling system according to claim 1, wherein, The pressure reduction device and the throttling state of the control valve create a situation where the internal pressure of the downstream portion of the control valve in the refrigerant flow path is lower than the internal pressure of the upstream portion of the control valve in the refrigerant flow path.

8. The cooling system according to claim 1, wherein, The refrigerant is a substance with a boiling point of 30°C or higher at atmospheric pressure.

9. The cooling system according to claim 8, wherein, The refrigerant has a GWP of 10 or less.

10. The cooling system according to claim 9, wherein, The refrigerant is HFO-1336mzz-Z.

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