Radiation cooling device

Abstract

To improve heat transfer efficiency from an exothermic body to a refrigerant in a constitution that the refrigerant evaporated by heat from the exothermic body moves to a member mounted to a container.SOLUTION: A radiation cooling device comprises: a container for housing an exothermic body and a refrigerant evaporated by heat of the exothermic body; and a bag body having a heat radiation property, mounted to the container, communicated with the container inside, and swollen upward in a gravity direction from the container together with evaporation of the refrigerant.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a radiative cooling device.

Background Art

[0002] Patent Document 1 discloses a radiative cooling device including a bag body and a working fluid. This bag body has a heat receiving portion connected to a heat generating body and a radiative cooling portion having heat radiation properties. Further, the working fluid is enclosed inside the bag body and transports heat from the heat receiving portion to the radiative cooling portion with a phase change. And the bag body of the radiative cooling device has softness, flexibility or stretchability and expands and contracts due to the phase change of the working fluid.

[0003] Patent Document 2 discloses a radiative cooling device including a bag body housed in a roll shape around a core body rotatable about an axis. The bag body of this radiative cooling device is provided with a heat receiving portion that receives heat from a core body connected to a heat generating body and a radiative cooling portion that radiates heat. Further, a working fluid that transports heat from the heat receiving portion to the radiative cooling portion with a phase change is enclosed inside the bag body. Inside the bag body, when the working fluid changes to a gas phase, the bag body expands due to an increase in internal pressure.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the case of the device of Patent Document 1, heat is transferred from a heat generating body disposed outside the bag body to the working fluid inside the bag body through a heat receiving portion that forms part of the bag body. For this reason, there is room for improvement in the heat transfer efficiency from the heat generating body to the working fluid.

[0006] In the case of the device of Patent Document 2 as well, similar to the device of Patent Document 1, heat is transferred from the heating element to the working fluid in the bag through the heat-receiving part that forms part of the bag from the core connected to the heating element. Therefore, there is room for improvement in the heat transfer efficiency from the heating element to the working fluid.

[0007] An object of the present disclosure is to improve the heat transfer efficiency from a heating element to a refrigerant in a configuration where the refrigerant vaporized by the heat of the heating element moves to a member attached to a container.

Means for Solving the Problems

[0008] The radiative cooling device according to the first aspect of the present disclosure includes a heating element, a container that houses the heating element and a refrigerant that vaporizes with the heat of the heating element, a bag having heat radiation properties, attached to the container and having its interior communicating with the interior of the container, and swelling upward in the gravitational direction from the container as the refrigerant vaporizes.

[0009] In the radiative cooling device according to the first aspect, when the refrigerant in the container is vaporized by the heat of the heating element, the vaporized refrigerant (vapor) moves into the bag as a member attached to the container. Due to the movement of the vapor, the bag swells upward in the gravitational direction from the container. When the heat of the vapor is transferred to the bag, the thermal energy of the transferred heat is radiated from the bag as electromagnetic waves. Also, when the heat of the vapor is taken away from the bag, the vapor liquefies. That is, the refrigerant condenses from the vapor into droplets. These droplets fall along the inner surface of the bag that has swelled upward in the gravitational direction due to their own weight and return to the container. In this way, in the above radiative cooling device, the heating element is cooled by the heat of the heating element being radiated through the bag.

[0010] Also, in the radiative cooling device according to the first aspect, the heating element and the refrigerant are housed in the container. Therefore, the heat of the heating element can be directly transferred to the refrigerant in the container. Thus, in the above radiative cooling device, the heat transfer efficiency from the heating element to the refrigerant is improved compared to a configuration where heat is transferred from the heating element disposed outside the container to the refrigerant in the container through a part of the container.

[0011] In the radiative cooling device according to the second aspect of the present disclosure, in the radiative cooling device according to the first aspect, the bag body bulges obliquely upward in the gravitational direction from the container.

[0012] In the radiative cooling device according to the second aspect, since the bag body bulges obliquely upward in the gravitational direction from the container, for example, compared with a configuration in which the bag body bulges directly upward in the gravitational direction from the container, it is possible to effectively utilize the space above the container.

[0013] The radiative cooling device according to the third aspect of the present disclosure is the radiative cooling device according to the first aspect, wherein the bag body is configured to be deployable and storable, and is deployed while bulging as the refrigerant vaporizes.

[0014] In the radiative cooling device according to the third aspect, when the bag body is in the stored state, the bag body is deployed while bulging as the refrigerant vaporizes. Here, in the above radiative cooling device, when the bag body is in the stored state, it is possible to effectively utilize the space around the container. And when the bag body is in the deployed state, the heat dissipation area increases compared with when it is in the stored state. Thereby, highly efficient heat dissipation becomes possible.

[0015] The radiative cooling device according to the fourth aspect of the present disclosure is the radiative cooling device according to the first aspect, wherein the container is a rigid body.

[0016] In the radiative cooling device according to the fourth aspect, since the container is a rigid body, it is possible to suppress damage to the container due to the pressure increase in the container accompanying the vaporization of the refrigerant. Also, it is possible to support the bag body that bulges upward in the gravitational direction from the container.

[0017] The radiative cooling device according to the fifth aspect of the present disclosure is the radiative cooling device according to the first aspect, wherein a plurality of the bag bodies are attached to one of the containers.

[0018] In the radiative cooling device according to the fifth aspect, by attaching a plurality of bag bodies to one container, for example, the cooling rate of the heating element is improved compared with a configuration in which one bag body is attached to one container.

[0019] The radiation cooling device according to the sixth aspect of the present disclosure is the radiation cooling device according to the first aspect, wherein the container has a cylindrical mounting port that is inserted into the entrance / exit portion of the bag body, and a tapered portion is provided on the outer periphery of the tip of the mounting port.

[0020] In the radiation cooling device according to the sixth aspect, since a tapered portion is provided on the outer periphery of the tip of the mounting port in the container, when inserting the outer periphery of the tip of the mounting port into the entrance / exit portion of the bag body, the tapered portion on the outer periphery of the tip serves as a guide for the entrance / exit portion. Thus, in the above radiation cooling device, for example, compared with a configuration in which the outer periphery of the tip of the mounting port has a constant diameter, it becomes easier to insert the mounting port into the entrance / exit portion of the bag body.

[0021] The radiation cooling device according to the seventh aspect of the present disclosure is the radiation cooling device according to the sixth aspect, further comprising a holding member that holds the state in which the mounting port is inserted into the entrance / exit portion of the bag body by sandwiching the bag body between the mounting port.

[0022] In the radiation cooling device according to the seventh aspect, the state in which the mounting port is inserted into the entrance / exit portion of the bag body is held by sandwiching the bag body between the mounting port and the holding member. Therefore, in the above radiation cooling device, for example, compared with a configuration that suppresses the mounting port from coming off the bag body due to the frictional force between the mounting port (tapered portion) and the entrance / exit portion of the bag body, it is possible to suppress the bag body from coming off the mounting port of the container due to an increase in internal pressure. That is, even if the internal pressure in the container rises due to the vaporization of the refrigerant, the holding portion can hold the bag body to the mounting port of the container.

[0023] The radiation cooling device according to the eighth aspect of the present disclosure is the radiation cooling device according to the first aspect, wherein the heat radiation property of the bag body has a solar reflectance of more than 80% and an infrared emissivity of more than 50%.

[0024] In the radiation cooling device according to the eighth aspect, since the bag body has a heat radiation property with a solar reflectance of more than 80% and an infrared emissivity of more than 50%, high-efficiency heat dissipation becomes possible.

[0025] The radiative cooling device according to the ninth aspect of the present disclosure includes a heating element, a container that houses the heating element and a refrigerant that vaporizes with the heat of the heating element, and a cylindrical body that has heat radiation properties, is formed in a cylindrical shape with a closed tip, is attached to the container, has an interior that communicates with the interior of the container, and has a tip positioned above the base end in the direction of gravity.

[0026] In the radiative cooling device according to the ninth aspect, when the refrigerant in the container vaporizes due to the heat of the heating element, the vaporized refrigerant (vapor) moves into the cylindrical body as a member attached to the container. Then, when the heat of the vapor is transferred to the cylindrical body, the thermal energy of the transferred heat is emitted from the cylindrical body as electromagnetic waves. Also, when the heat of the vapor is taken away by the cylindrical body, the vapor liquefies. That is, the refrigerant condenses from the vapor into droplets. These droplets fall along the inner surface of the cylindrical body, where the tip is positioned above the base end in the direction of gravity, and return to the container. In this way, in the above radiative cooling device, the heating element is cooled by the heat of the heating element being radiated through the cylindrical body.

[0027] Also, in the above radiative cooling device, the heating element and the refrigerant are housed in the container. Therefore, the heat of the heating element can be directly transferred to the refrigerant in the container. Thus, in the above radiative cooling device, compared with a configuration in which heat is transferred from a heating element disposed outside the container to the refrigerant in the container through a part of the container, the heat transfer efficiency from the heating element to the refrigerant is improved.

Advantages of the Invention

[0028] According to the present disclosure, in a configuration in which a refrigerant vaporized by heat from a heating element moves to a member attached to a container, the heat transfer efficiency from the heating element to the refrigerant can be improved.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0030] Hereinafter, embodiments for carrying out the present disclosure will be described based on the drawings. Components denoted by the same reference numerals in each drawing mean the same or similar components. In the embodiments described below, redundant descriptions and reference numerals may be omitted. In addition, the drawings used in the following description are all schematic, and the dimensional relationships and ratios of the respective elements shown in the drawings do not necessarily match the actual ones. Also, the dimensional relationships and ratios of the respective elements do not necessarily match even between multiple drawings.

[0031] As shown in FIG. 1, a radiative cooling device 20 according to an embodiment of the present disclosure includes a container 30 and a bag body 40.

[0032] (Container 30) As shown in FIG. 1, the container 30 houses a heating element HE and a refrigerant F that vaporizes with the heat of the heating element HE. This container 30 has a ceiling portion 30A, a bottom portion 30B, and side wall portions 30C. In the present embodiment, as an example, the container 30 is in the shape of a rectangular box.

[0033] Further, the upper part of one of the four side wall portions 30C is inclined obliquely. This inclined portion will be hereinafter referred to as the inclined portion 32 as appropriate. Also, the side wall portion 30C having the inclined portion 32 will be referred to as the side wall portion 30C1 as appropriate. This inclined portion 32 is inclined toward the inside of the container 30.

[0034] A through-hole 32A is formed in the inclined portion 32. A cylindrical mounting port 34 is fixed to the outer surface of the inclined portion 32 so as to communicate with the through-hole 32A. Further, the mounting port 34 is fixed to the inclined portion 32 on the upper side in the direction of gravity (the side in the direction indicated by the arrow UP), specifically, so as to face obliquely upward in the direction of gravity. As shown in FIGS. 4 and 5, this mounting port 34 has a cylindrical portion 34A, a flange portion 34B, and a tapered portion 34C.

[0035] As shown in FIG. 4, the flange portion 34B is an overhanging portion that projects radially outward from one end side in the axial direction of the cylindrical portion 34A. This flange portion 34B is fixed to the peripheral portion of the through-hole 32A in the inclined portion 32 (see FIG. 1). The fixing method of the flange portion 34B to the inclined portion 32 is not particularly limited. For example, fastening with a fastening component such as a screw may be used, fixing with an adhesive may be used, or welding may be used. Further, as long as the mounting port 34 can be fixed to the inclined portion 32, it is not limited to the above fixing method.

[0036] As shown in FIG. 4, the tapered portion 34C is formed at the other end in the axial direction of the cylindrical portion 34A. Specifically, the tapered portion 34C is a portion of the cylindrical portion 34A that tapers toward the other end in the axial direction of the cylindrical portion 34A. In FIG. 5, the minimum diameter of the tapered portion 34C is D min , and the maximum diameter is D max are shown. In FIG. 5, the inner diameter of the entrance / exit portion 40A of the bag body 40 is indicated by 40D. As shown in FIGS. 1 and 6, the entrance / exit portion 40A of the bag body 40 is in contact with this tapered portion 34C. Specifically, the inner surface constituting the entrance / exit portion 40A of the bag body 40 is in contact with the surface of the mounting port 34 constituting the tapered portion 34C.

[0037] Further, the container 30 of the present embodiment is a rigid body. Specifically, the container 30 is formed of a metal material. As the metal material, for example, iron, copper, or an aluminum alloy may be used. It should be noted that the metal material constituting the container 30 is preferably a metal material having a Young's modulus of 70 Mpa or more.

[0038] As shown in FIG. 1, the inside of the container 30 contains, in other words, stores, the refrigerant F. The heating element HE is immersed in the stored refrigerant F. The heating element HE of the present embodiment is, as an example, a metal pipe that penetrates the container 30. The pipe penetrates the side wall portions 30C on both sides adjacent to the side wall portion 30C1. Refrigerant flows inside the pipe. This refrigerant exchanges heat with the refrigerant F through the pipe.

[0039] As the refrigerant F contained in the container 30, for example, water or alternative Freon etc. may be used. Note that the type of the refrigerant F is not limited to these.

[0040] (Bag body 40) As shown in FIG. 1, the bag body 40 has heat radiation, is attached to the container 30, and its inside communicates with the inside of the container 30, and is configured to expand upward in the gravitational direction from the container 30 as the refrigerant F vaporizes. Specifically, the bag body 40 is in a cylindrical shape with a closed tip. The base end of this bag body 40 constitutes an entrance / exit portion 40A. The entrance / exit portion 40A of the bag body 40 is attached to the attachment port 34 as shown in FIG. 6. Specifically, the attachment port 34 is inserted into the entrance / exit portion 40A of the bag body 40. Therefore, the inside of the bag body 40 communicates with the inside of the container 30 through the attachment port 34. Also, in a state where the attachment port 34 is inserted into the entrance / exit portion 40A of the bag body 40, the attachment port 34 is held in a state of being inserted into the entrance / exit portion 40A of the bag body 40 by sandwiching the entrance / exit portion 40A of the bag body 40 between the tapered portion 34C of the attachment port 34 and the inclined inner peripheral surface 70A of the annular holding member 70. Note that, for example, grease etc. may be applied to the tapered portion 34C and then the bag body 40 may be attached. By doing so, the tapered portion 34C and the bag body 40 are likely to be in close contact, and the sealing performance is improved. In the present embodiment, the holding member 70 is fixed to the flange portion 34B of the attachment port 34 using a fastening component such as a screw (not shown).

[0041] As described above, since the base end (entrance / exits section 40A) of the bag body 40 is attached to the attachment port 34, the tip end is a free end. Therefore, when the vaporized refrigerant (hereinafter, the vaporized refrigerant is referred to as "vapor V") moves from the container 30 to the bag body 40 in a deflated state, the bag body 40 expands. Here, since the attachment port 34 faces upward in the direction of gravity, specifically, obliquely upward in the direction of gravity, the cylindrical bag body 40 also expands upward in the direction of gravity from the container 30, specifically, obliquely upward in the direction of gravity.

[0042] Note that FIG. 1 shows a state in which the bag body 40 is expanded and deployed. When the refrigerant F is in a liquid phase state (liquefied state), the bag body 40 deflates and enters a stored state. The stored state of the bag body 40 may be, for example, a state of being wound up in a roll shape, a folded state, or is not particularly limited.

[0043] In addition, in this embodiment, one bag body 40 is attached to one container 30, but the present disclosure is not limited to this configuration. A plurality of bag bodies 40 may be attached to one container 30. In this case, the expanding directions of the respective bag bodies 40 may be different from each other or the same. Further, for example, the bag body 40 may be attached to the ceiling portion 30A of the container 30. However, when the expanding directions of the respective bag bodies 40 are made the same, an effect of effectively utilizing the space around the container 30 can be obtained.

[0044] Further, the bag body 40 preferably has a softness such that it can be deployed and stored.

[0045] As shown in FIG. 2, the bag body 40 is a bag body having a multilayer structure. The bag body 40 includes a radiative cooling layer 42 and a reflective layer 44. Further, the bag body 40 may include a protective layer 46.

[0046] <Radiative cooling layer 42> The radiative cooling layer 42 forms the outermost layer of the bag body 40. This radiative cooling layer 42 has heat radiation properties and light transmissivity that allows sunlight (including visible light) to pass through. The radiative cooling layer 42 is preferably composed of a material with a sunlight transmittance exceeding 80% and an infrared light emissivity exceeding 50%. Such a material constituting the radiative cooling layer 42 preferably includes a transparent fluororesin. As the transparent fluororesin, tetrafluoroethylene - hexafluoropropylene copolymer (FEP), perfluoroalkoxyethyl ether copolymer (PFA), or ethylene tetrafluoroethylene copolymer (ETFE) may be used.

[0047] <Reflective layer 44> The reflective layer 44 forms a layer inside the radiative cooling layer 42 of the bag body 40. This reflective layer 44 has light reflectivity for reflecting sunlight. The reflective layer 44 is preferably composed of a material with a sunlight reflectivity of 80% or more. Also, the reflective layer 44 is preferably composed of a metal material. Examples of the metal material constituting the reflective layer 44 include silver and aluminum. Also, for improving the reflectivity, it is preferable to form an electrolytically polished surface on the aluminum. Note that as long as it can reflect sunlight VL, the material of the reflective layer 44 is not limited.

[0048] <Protective layer 46> The protective layer 46 forms the innermost layer of the bag body 40. This protective layer 46 is a layer for protecting the reflective layer 44. The protective layer 46 is composed of a material having corrosion resistance and abrasion resistance equal to or higher than that of the reflective layer 44. The material constituting the protective layer 46 preferably includes Inconel. Also, the material constituting the protective layer 46 may include stainless steel.

[0049] Further, the bag body 40 of the present embodiment has a joint portion 40B formed by welding the outer surface 41O and the inner surface 41I of the film 41 constituting the radiation cooling layer 42 (see FIG. 3A). As shown in FIG. 3B, this joint portion 40B is formed by welding the ends of the radiation cooling layers 42 on both sides of the film 41 together after removing the reflective layer 44 and the protective layer 46 in such a manner that the ends of the radiation cooling layers 42 on both sides of the film 41 overlap each other. This joint portion 40B is formed along the longitudinal direction of the bag body 40 (in the direction of the central axis CL in the inflated state).

[0050] Here, as shown in FIG. 1, when the refrigerant F is heated by the heat of the heating element HE and undergoes a phase change from the liquid phase to the gas phase (vaporization), vapor V is generated. Then, as the refrigerant F vaporizes, the internal pressure of the bag body 40 increases, and the bag body 40 expands and unfolds upward in the direction of gravity.

[0051] The heat of the vapor V generated inside the bag body 40 is transmitted from the inner surface of the bag body 40 to the radiation cooling layer 42, and the thermal energy of the transmitted heat is radiated as electromagnetic waves EW (including infrared light). Further, when the heat of the vapor V is thus taken away by the radiation cooling layer 42, the vapor V changes from the gas phase to the liquid phase, and the vapor V is condensed into droplets D. These droplets D fall due to their own weight.

[0052] By repeating the above operations, by means of the so-called thermosiphon method, the heat of the heating element HE is transferred to the radiation cooling layer 42 of the bag body 40 along with the phase change of the refrigerant F, and the thermal energy is radiated as electromagnetic waves EW from the radiation cooling layer 42, thereby cooling the heating element HE.

[0053] When the heating element HE is cooled and the temperature inside the container 30 decreases, the internal pressure of the bag body 40 decreases, and the bag body 40 begins to deflate from the inflated state. At this time, the bag body 40 is, for example, wound up in a roll shape or folded to enter a storage state.

[0054] As described above, the container 30 and the bag body 40 of the present embodiment constitute a radiation cooling device 20 having a function as a radiator that emits the thermal energy of the heating element HE that generates heat as electromagnetic waves EW to cool the heating element HE.

[0055] Next, the operation of this embodiment will be described. In the radiative cooling device 20 of this embodiment, as described above, when the refrigerant F in the container 30 is vaporized by the heat of the heating element HE, the vaporized refrigerant (vapor V) moves into the bag body 40 attached to the container 30. Due to the movement of the vapor V, the bag body 40 bulges upward in the gravitational direction from the container 30. Then, when the heat of the vapor is transferred to the bag body 40, the thermal energy of the transferred heat is emitted from the bag body 40 as electromagnetic waves EW. Also, when the heat of the vapor V is taken away from the bag body 40, the vapor V liquefies. That is, the refrigerant F condenses from the vapor V into droplets D. These droplets D fall along the inner surface of the bag body 40 that has bulged upward in the gravitational direction due to their own weight and return to the inside of the container 30. In this way, in the radiative cooling device 20, the heating element HE is cooled by the heat of the heating element HE being radiated through the bag body 40.

[0056] Also, in the radiative cooling device 20 of this embodiment, the heating element HE and the refrigerant F are accommodated in the container 30. Therefore, the heat of the heating element HE can be directly transferred to the refrigerant F in the container 30. Thus, in the radiative cooling device 20, compared with a configuration in which heat is transferred from the heating element HE disposed outside the container 30 to the refrigerant F in the container 30 through a part of the container 30, the heat transfer efficiency from the heating element HE to the refrigerant F is improved.

[0057] Also, in the radiative cooling device 20 of this embodiment, since the bag body 40 bulges obliquely upward in the gravitational direction from the container 30, for example, compared with a configuration in which the bag body 40 bulges directly upward in the gravitational direction from the container 30, it becomes possible to effectively utilize the space above the container 30.

[0058] Also, in the radiative cooling device 20 of this embodiment, when the bag body 40 is in the stored state, the bag body 40 is expanded while bulging as the refrigerant F vaporizes. Here, in the radiative cooling device 20, when the bag body 40 is in the stored state, it becomes possible to effectively utilize the space around the container 30. And when the bag body 40 is in the deployed state, the heat dissipation area increases compared with when it is in the stored state. Thereby, highly efficient heat dissipation becomes possible.

[0059] Further, in the radiative cooling device 20 of the present embodiment, since the container 30 is a rigid body, damage to the container 30 due to the pressure increase in the container 30 accompanying the vaporization of the refrigerant F can be suppressed. Further, the bag body 40 that bulges upward in the gravitational direction from the container 30 can be supported.

[0060] Further, in the radiative cooling device 20 of the present embodiment, by attaching a plurality of bag bodies 40 to one container 30, for example, the cooling rate of the heating element HE is improved as compared with a configuration in which one bag body 40 is attached to one container 30.

[0061] Further, in the radiative cooling device 20 of the present embodiment, since the tapered portion 34C is provided on the outer periphery of the tip of the attachment port 34 in the container 30, when the outer periphery of the tip of the attachment port 34 is inserted into the entrance / exit portion 40A of the bag body 40, the tapered portion 34C on the outer periphery of the tip serves as a guide for the entrance / exit portion 40A. As a result, in the radiative cooling device 20, for example, it is easier to insert the attachment port 34 into the entrance / exit portion 40A of the bag body 40 as compared with a configuration in which the outer periphery of the tip of the attachment port 34 has a constant diameter.

[0062] Further, in the radiative cooling device 20 of the present embodiment, the state in which the attachment port 34 is inserted into the entrance / exit portion 40A of the bag body 40 is held by sandwiching the bag body 40 between the attachment port 34 and the holding member 70. Therefore, in the radiative cooling device 20, for example, it is possible to suppress the detachment of the attachment port 34 from the bag body 40 due to an increase in internal pressure as compared with a configuration that suppresses the detachment of the attachment port 34 from the bag body 40 by the frictional force between the attachment port 34 (tapered portion 34C) and the entrance / exit portion 40A of the bag body 40. That is, even if the internal pressure in the container 30 increases due to the vaporization of the refrigerant F, the bag body 40 can be held at the attachment port 34 of the container 30 by the holding member 70.

[0063] Further, in the radiative cooling device 20 of the present embodiment, since the bag body 40 has a heat radiation property with a solar reflectance of more than 80% and an infrared radiation rate of more than 50%, high-efficiency heat dissipation becomes possible.

[0064] [Other Embodiments] In the radiative cooling device 20 of the foregoing embodiment, the bag body 40 has flexibility to the extent that it can be deployed and stored, but the present disclosure is not limited to this configuration. For example, the bag body 40 may not have flexibility, in other words, the bag body 40 may be configured in a cylindrical shape and attached to the container 30 such that the tip of the cylinder is located above the base end in the direction of gravity. Even in a configuration where the cylindrical shape of the bag body 40 is maintained in this way, the bag body 40 can take heat from the vaporized refrigerant F and dissipate heat. Further, a cylindrical body whose cylindrical shape is maintained may be used instead of the bag body 40.

[0065] [Application Example] Next, examples to which the technology of the present disclosure is applicable will be described.

[0066] As shown in FIG. 7, the radiative cooling device 20 in the foregoing embodiment may be used, for example, as a radiator of an outdoor unit 82 installed on the roof of a building 80. That is, the radiative cooling device 20 functions as a radiator of the outdoor unit when a pipe as a heat generating body HE is connected to the outdoor unit. Thereby, the heat of the outdoor unit can be radiated as electromagnetic waves EW from the radiative cooling layer 42. The building 80 is, for example, a building, a factory, or the like. According to this application example, the cooling of the outdoor unit that requires a large output can be efficiently performed. Further, since the performance of the outdoor unit improves as the ambient temperature becomes lower, further performance improvement of the outdoor unit can be expected by using the radiative cooling device 20. Note that the above application example of the present disclosure is merely an example.

[0067] Although one embodiment of the technology disclosed in the present application has been described above, the technology disclosed in the present application is not limited to the above, and it goes without saying that various modifications can be made without departing from the gist thereof.

[0068] Regarding the above embodiments, the following is further disclosed.

[0069] (Supplementary Note 1) A container that houses a heat generating body and a refrigerant that vaporizes with the heat of the heat generating body, It has heat radiation, is attached to the container, has an interior that communicates with the interior of the container, and is a bag that expands upward in the gravitational direction from the container as the refrigerant vaporizes, and A radiative cooling device comprising

[0070] (Appendix 2) The bag expands obliquely upward in the gravitational direction from the container. The radiative cooling device according to Appendix 1.

[0071] (Appendix 3) The bag is configured to be deployable and storable, and is deployed while expanding as the refrigerant vaporizes. The radiative cooling device according to Appendix 1 or Appendix 2.

[0072] (Appendix 4) The container is a rigid body. The radiative cooling device according to any one of Appendices 1 to 3.

[0073] (Appendix 5) A plurality of the bags are attached to one of the containers. The radiative cooling device according to any one of Appendices 1 to 4.

[0074] (Appendix 6) The container has a cylindrical attachment port that is inserted into the inlet / outlet portion of the bag, The tip outer periphery of the attachment port has a tapered portion. The radiative cooling device according to any one of Appendices 1 to 5.

[0075] (Appendix 7) The radiative cooling device according to Appendix 6, further comprising a holding member that holds the attachment port inserted into the inlet / outlet portion of the bag by sandwiching the bag between the attachment port.

[0076] (Appendix 8) The heat radiation of the bag has a solar reflectance of more than 80% and an infrared emissivity of more than 50%. The radiative cooling device according to any one of Appendices 1 to 7.

[0077] (Appendix 9) A heating element, a container that houses the heating element and a refrigerant that vaporizes with the heat of the heating element, A cylindrical body having heat radiation, formed in a cylindrical shape with a closed tip, attached to the container, having an interior that communicates with the interior of the container, and having a tip positioned above the base end in the direction of gravity. A radiation cooling device comprising the above.

Explanation of Signs

[0078] 20 Radiation cooling device 30 Container 34 Mounting port 40 Bag body 40A Entrance / exit part 40B Joint part 41 Film 41I Inner surface 41O Outer surface 70 Holding member F Refrigerant HE Heating element

Claims

1. A container that houses a heating element and a refrigerant that vaporizes with the heat of the heating element, a bag having heat radiation, attached to the container with its interior communicating with the interior of the container, and swelling upward in the gravitational direction from the container as the refrigerant vaporizes, A radiation cooling device comprising:

2. The radiation cooling device according to claim 1, wherein the bag swells obliquely upward in the gravitational direction from the container.

3. The radiation cooling device according to claim 1, wherein the bag is configured to be deployable and retractable, and is deployed while swelling as the refrigerant vaporizes.

4. The radiation cooling device according to claim 1, wherein the container is a rigid body.

5. The radiation cooling device according to claim 1, wherein a plurality of the bags are attached to one container.

6. The container has a cylindrical attachment port that is inserted into an inlet / outlet portion of the bag, The radiation cooling device according to claim 1, having a tapered portion on the outer periphery of the tip of the attachment port.

7. The radiation cooling device according to claim 6, further comprising a holding member that holds the attachment port inserted into the inlet / outlet portion of the bag by sandwiching the bag between the attachment port.

8. The radiation cooling device according to claim 1, wherein the heat radiation of the bag has a solar reflectance of more than 80% and an infrared radiation rate of more than 50%.

9. A container that houses a heating element and a refrigerant that vaporizes with the heat of the heating element, a cylindrical body having heat radiation, formed in a cylindrical shape with a closed tip, attached to the container with its interior communicating with the interior of the container, and having the tip positioned above the base end in the gravitational direction, A radiation cooling device comprising:

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