Radiative cooling device

Abstract

The purpose of the present invention is to provide a radiative cooling device that, by incorporating an infrared radiating section equipped with a heat collection-enhancing structure, can efficiently collect heat from the object to be cooled into the infrared radiating section without providing a special structure, and that, by incorporating a temperature rise suppression structure reliably preventing heat inflow from an external space to the infrared radiating section and irradiation thereof with sunlight, can lower the final temperature of the infrared radiating section during radiative cooling and ensure high cooling efficiency.　The radiative cooling device includes: a heat collection part 2 composed of a plate-like heat receiving fin 8 disposed in the object to be cooled; an infrared radiating section 3 in which the heat receiving fin 8 is implanted on a heat receiving surface 3a1 on the side of the object to be cooled to enable the inflow of heat, and the inflow heat is radiated as far-infrared rays from a radiation surface 3b1 on the opposite side; an opening window 12 which is provided in a partition wall 11 separating the infrared radiating section from an external space and through which the far-infrared rays from the radiation surface 3b1 are radiated to the external space; and a temperature rise suppression structure 4 preventing heat inflow from the outdoors 6 to the infrared radiating section 3 through the opening window 12 and irradiation of the infrared radiating section with sunlight.

Description

radiation cooling device

[0001] The present invention relates to a radiative cooling device comprising: a heat collection promotion structure that promotes heat collection from a cooling target; an infrared radiation section from which heat flows into a heat receiving surface by the heat collection promotion structure, while the incoming heat is radiated as far-infrared rays from a radiating surface opposite to the heat receiving surface; and a discharge section provided in a partition wall separating the infrared radiation section from the external space, which emits far-infrared rays from the radiating surface into the external space. More specifically, the present invention relates to a radiative cooling device that, by providing an infrared radiation section with a heat collection promotion structure, enables efficient heat collection from a cooling target to the infrared radiation section without the need for special structures; and further, by providing a temperature rise suppression structure that reliably prevents heat inflow from the external space and irradiation by sunlight to the infrared radiation section, the temperature reached by the infrared radiation section during radiative cooling is lowered, thereby ensuring high cooling efficiency even in various environments.

[0002] Conventionally, various cooling devices (hereinafter referred to as "radiative cooling devices") have been considered that can cool objects without consuming electrical energy by utilizing the phenomenon known as "radiative cooling," in which an object emits electromagnetic waves into its surroundings and its temperature decreases.

[0003] For example, a known technique exists in which a radiator (hereinafter referred to as the "infrared radiating section") is constructed from a selectively transparent layer that transmits sunlight and emits far-infrared rays, and a reflective layer in close contact with its back surface. Heat transmitted by heat conduction from a cooling object in contact with the back surface of the infrared radiating section is radiated into the external space as far-infrared rays from the surface of the selectively transparent layer, while sunlight that has passed through the selectively transparent layer is reflected by the reflective layer on the back surface, passes through the selectively transparent layer again, and then emitted into the external space. This suppresses heat inflow into the infrared radiating section due to sunlight irradiation, thereby lowering the temperature reached by the infrared radiating section during radiative cooling (see, for example, Patent Document 1).

[0004] In addition, the infrared radiation part is composed of a single member, and the heat conducted by heat conduction from the cooling object contacting the back surface of the infrared radiation part is radiated as far-infrared rays from the surface of the infrared radiation part. Between this infrared radiation part and a window member that reflects sunlight with the outermost reflective layer and transmits the far-infrared rays from the infrared radiation part to the external space, by interposing a transparent intermediate heat insulating material, heat inflow due to heat conduction from the window member exposed to the external space to the infrared radiation part is suppressed, and a technique for lowering the temperature reached by the infrared radiation part during radiative cooling is also known (see, for example, Patent Document 2).

[0005] Japanese Patent Application Laid-Open No. 2019-66101, Patent No. 6602487

[0006] However, in the radiative cooling device described in Patent Document 1, in order not to prevent heat conduction from the cooling object into the selective transmission layer, even a reflective layer with a small thermal resistance needs to be made as thin as possible. For this reason, when the intensity of sunlight is strong, there is a risk that the sunlight is not sufficiently reflected and is absorbed, causing the temperature of the infrared radiation part to rise, and heat inflow due to sunlight irradiation cannot be reliably suppressed, resulting in a high temperature reached by the infrared radiation part during radiative cooling and a low cooling efficiency because the temperature of the cooling object does not easily drop.

[0007] Furthermore, in the radiative cooling device described in Patent Document 2, the side surface of the infrared radiation part is surrounded by the inner wall of the heat insulating container, the cooling object contacts the back surface, and the surface is covered with the intermediate heat insulating material. The infrared radiation part is housed in a heat insulating space completely separated from the surroundings. Therefore, as in Patent Document 1, the heat transfer from the cooling object to the infrared radiation part depends only on heat conduction through a single contact surface with the cooling object, and since heat from the cooling object is not efficiently collected, there is a problem that heat collection becomes the rate-determining factor and the cooling efficiency is low.

[0008] The present invention was conceived in view of the above points, and aims to provide a radiative cooling device that can efficiently collect heat from the object to be cooled into the infrared radiator without providing a special structure by equipping it with an infrared radiator with a heat collection promotion structure, and further, by equipping it with a temperature rise suppression structure that reliably prevents heat inflow from the external space and irradiation by sunlight into the infrared radiator, thereby lowering the temperature reached by the infrared radiator during radiative cooling and ensuring high cooling efficiency even in various environments.

[0009] To achieve the above objectives, the present invention comprises: a heat collection promoting structure that promotes heat collection from a cooling target; an infrared radiation section in which heat flows into a heat receiving surface by the heat collection promoting structure, while the incoming heat is radiated as far-infrared rays from a radiating surface opposite to the heat receiving surface; a discharge section provided in a partition wall separating the infrared radiation section from the external space and emitting far-infrared rays from the radiating surface into the external space; and a temperature rise suppression structure between the radiating surface and the external space that prevents heat inflow from the external space to the infrared radiation section via the discharge section and irradiation by sunlight, thereby suppressing the temperature rise of the infrared radiation section.

[0010] Furthermore, a heat collection promotion structure is provided to facilitate heat collection from the object to be cooled. By using this heat collection promotion structure to allow heat to flow into the heat receiving surface of the infrared radiation unit, heat from the object to be cooled can be efficiently collected by the infrared radiation unit.

[0011] Furthermore, by incorporating a temperature rise suppression structure between the infrared radiation surface and the external space that reliably prevents heat inflow from the external space to the infrared radiation surface via the emission section and irradiation by sunlight, the temperature rise of the infrared radiation surface is suppressed, the temperature reached by the infrared radiation surface during radiative cooling is lowered, and high cooling efficiency can be ensured even under various environmental conditions.

[0012] Furthermore, the present invention provides a heat collection promotion structure having a heat collection section in which plate-shaped heat receiving fins, which are embedded in the heat receiving surface and into which heat flows, are arranged in the fluid to be cooled.

[0013] In this case, the heat collection area is increased by using multiple heat receiving fins arranged in a row, and the generation of thermal convection is promoted by temperature differences between the heat receiving fins and the surroundings. This allows heat from the object to be cooled to be collected more efficiently into the infrared radiating part by thermal conduction and thermal convection without the need for a special structure.

[0014] Furthermore, the present invention relates to an opening window in a partition wall that is substantially the same shape and area as the infrared radiation section, wherein the infrared radiation section is covered on the side of the opening window that is to be cooled, and the temperature rise suppression structure comprises a far-infrared transparent window insulation material fitted in the opening window on the side of the opening window that is closer to the external space than the infrared radiation section, a shade erected on the side of the opening window that blocks sunlight, and a removable structure that allows the shade to be replaced and incorporated according to the installation conditions of the opening window.

[0015] In this case, a simple configuration is provided in which an infrared radiation unit with a heat collector is installed on the side of the object to be cooled, and a transparent insulating material or shade is attached to the opposite side of the window, allowing for radiative cooling of objects of various sizes and temperatures, thus providing a highly versatile radiative cooling device.

[0016] Furthermore, the temperature rise suppression structure has a far-infrared transparent window insulation material fitted into the opening window on the side of the infrared radiation section that is closer to the outside space. As a result, far-infrared rays emitted from the radiation surface of the infrared radiation section pass through the transparent window insulation material in the opening window and are released into the outside space, while heat from the outside space is blocked by the transparent window insulation material, preventing heat from flowing into the infrared radiation section.

[0017] Furthermore, the temperature rise suppression structure has a shade erected on the external side of the opening window to block sunlight. As described above, far-infrared rays pass through the opening window and the transparent insulation material inside the window and are emitted into the external space, while sunlight is blocked by the shade, preventing sunlight from irradiating the infrared radiation part through the transparent insulation material inside the window and the opening window.

[0018] In addition, the temperature rise suppression structure has a detachable structure that allows for the replacement of shades optimized according to the installation conditions of the opening window. Therefore, even if the installation position or orientation of the opening window changes, it can be accommodated simply by changing the size and shape of the shade, thereby reducing equipment costs and improving maintainability.

[0019] The present invention provides an opening window in a partition wall, wherein the emission section is substantially the same shape and area as the infrared radiation section, and the infrared radiation section is covered on the side of the opening window that is to be cooled. The temperature rise suppression structure comprises a far-infrared transparent window insulation material fitted in the opening window on the side of the opening window that is closer to the external space than the infrared radiation section, a shade erected on the side of the opening window that blocks sunlight, and a switching mechanism that can switch between a state of sunlight transmission and a state of light blocking.

[0020] In this case, a simple configuration is provided in which an infrared radiation unit with a heat collector is installed on the side of the object to be cooled, and a transparent insulating material or shade is attached to the opposite side of the window, allowing for radiative cooling of objects of various sizes and temperatures, thus providing a highly versatile radiative cooling device.

[0021] Furthermore, the temperature rise suppression structure has a far-infrared transparent window insulation material fitted into the opening window on the side of the infrared radiation section that is closer to the outside space. As a result, far-infrared rays emitted from the radiation surface of the infrared radiation section pass through the transparent window insulation material in the opening window and are released into the outside space, while heat from the outside space is blocked by the transparent window insulation material, preventing heat from flowing into the infrared radiation section.

[0022] Furthermore, the temperature rise suppression structure has a shade erected on the external side of the opening window to block sunlight. As described above, far-infrared rays pass through the opening window and the transparent insulation material inside the window and are emitted into the external space, while sunlight is blocked by the shade, preventing sunlight from irradiating the infrared radiation part through the transparent insulation material inside the window and the opening window.

[0023] In addition, the temperature rise suppression structure has a switching mechanism that can switch between a state where sunlight is transmitted and a state where sunlight is blocked. Therefore, during the day, sunlight is reliably blocked, and only at night when there is no sunlight, far-infrared rays are emitted into the outside space, thereby more reliably preventing sunlight from irradiating the infrared radiation part.

[0024] Furthermore, the present invention includes a dimming panel in which the switching mechanism can automatically switch between a transparent state in which sunlight is transmitted and an opaque state in which the transmission of sunlight is blocked, depending on whether it is day or night.

[0025] In this case, the dimming panel is a thin plate shape with no movable parts and requires little installation space, so it can be installed even in the narrow space between the infrared radiating unit and the transparent insulation material inside the window, and the radiative cooling device can be made more compact by miniaturizing the emitting unit.

[0026] Furthermore, the present invention includes a shutter body that can automatically switch between an open state and a closed state of the opening window between day and night by a movement operation.

[0027] In this case, the opening and closing device that opens and closes the opening window by rotating or sliding the shutter body has a simple structure, and the materials of the components can be inexpensive, thus reducing the cost of the device and improving maintainability.

[0028] Furthermore, the present invention includes a light-blocking curtain that can automatically switch between an open state and a closed state of the opening window between day and night by winding and unwinding operations.

[0029] In this case, the opening and closing device that operates the blackout curtain to open and close the window has a simple structure, and the materials of its components can be inexpensive, thus reducing the cost of the device and improving maintainability.

[0030] Furthermore, the present invention provides a power supply device that is installed in conjunction with the switching mechanism, the power supply device having a solar panel that supplies operating power for switching between the light-transmitting state and the light-blocking state, a battery that stores the operating power, and a control unit that controls the power supply timing for supplying operating power to the switching mechanism.

[0031] In this case, periodic battery replacement and manual switching operations become unnecessary, improving maintenance and reducing the workload. Furthermore, the accuracy of switching between sunlight transmission and shading states is improved, making it possible to more reliably prevent sunlight from irradiating the infrared emitting part.

[0032] Furthermore, the present invention provides a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, wherein the infrared radiation portion is positioned on the cooling target side of the small hole, and the temperature rise suppression structure comprises an infrared radiation portion having a substantially hemispherical radiating surface with a recess facing the partition wall side, the small hole provided on or near a far-infrared focusing point located at a distance from the infrared radiation portion, a cylindrical heat dissipation duct inserted into the small hole, and the substantially hemispherical radiating surface fitted to the end of the heat dissipation duct on the cooling target side. The device comprises a far-infrared transparent plano-concave lens that parallelizes multiple far-infrared rays from a surface and passes them through the heat dissipation duct, a far-infrared transparent duct insulation material fitted to the end of the heat dissipation duct on the external space side of the plano-concave lens, and a conical infrared guide portion that covers the recess of the infrared radiation portion with a bottom opening and connects the upper opening to a small hole in the partition wall, thereby reflecting and concentrating the multiple far-infrared rays emitted from the radiation surface with its inner circumferential surface and guiding them to the end of the heat dissipation duct on the side of the object to be cooled.

[0033] In this case, although an infrared radiator with a heat collector is positioned on the cooling target side of the small hole that emits far-infrared rays into the external space, this small hole is located on or near the far-infrared radiating point, which is spaced apart from the infrared radiating point. Therefore, heat inflow from the external space through the small hole and sunlight irradiation through the small hole can be prevented from reaching the infrared radiating point, thereby lowering the temperature reached by the infrared radiating point during radiative cooling and ensuring high cooling efficiency.

[0034] Furthermore, the temperature rise suppression structure has an infrared radiation section with a roughly hemispherical radiation surface in which the recess faces the partition wall. This allows for the concentration of far-infrared radiation emitted from a wide-area radiation surface, increasing the energy density, reducing far-infrared radiation loss, and improving cooling efficiency.

[0035] Furthermore, the temperature rise suppression structure includes a cylindrical heat dissipation duct that is inserted into a small hole, and a plano-concave lens fitted to the end of the heat dissipation duct on the side of the object to be cooled, which parallelizes multiple far-infrared rays from the substantially hemispherical radiating surface and allows them to pass through the heat dissipation duct. As a result, the focused far-infrared rays are made into parallel light, which passes through the heat dissipation duct without scattering inside, and is emitted into the outside space through the transparent insulation material inside the duct. This reduces the scattering loss of far-infrared rays, further improving the cooling efficiency, and also prevents the backflow of heat to the infrared radiating part due to diffuse reflection during scattering.

[0036] In addition, the temperature rise suppression structure has a far-infrared transparent duct insulation material fitted to the end of the heat dissipation duct that is on the side of the plano-concave lens that is closer to the outside space. As a result, the parallelized far-infrared rays pass through the heat dissipation duct and through the transparent duct insulation material to be released into the outside space, while heat from the outside space is blocked by the transparent duct insulation material. This further ensures that heat inflow from the outside space into the infrared radiation part through the small holes is prevented.

[0037] Furthermore, the temperature rise suppression structure has a conical infrared guide section that covers the recess of the infrared radiation section with a bottom opening, while connecting the upper opening to a small hole in the partition wall. This section reflects and concentrates multiple far-infrared rays emitted from the approximately hemispherical radiation surface on its inner surface and guides them to the end on the cooling target side via a heat dissipation duct. This prevents multiple far-infrared rays emitted from the approximately hemispherical radiation surface from scattering far away from the concentration point and outside the radiative cooling device, and prevents the temperature of the infrared radiation section from rising due to far-infrared rays originating from fluids other than the cooling target being irradiated from the outside, thereby ensuring even higher cooling efficiency.

[0038] Furthermore, the present invention provides a structure in which the emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, the infrared radiation portion is positioned on the cooling target side of the small hole, and the temperature rise suppression structure comprises an infrared radiation portion having a substantially hemispherical radiation surface with a recess facing the partition wall side, the small hole provided on or near the far-infrared focusing point located at a distance from the infrared radiation portion, and a component inserted into the small hole, with an oblique cut portion at the tip on the external space side, and a composite radiation emitted from the radiation surface. The device includes a cylindrical heat dissipation duct that reflects multiple far-infrared rays from its inner surface and emits them into the external space from the diagonal cut section, a transparent heat insulating material that is far-infrared transparent and fitted into the diagonal cut section of the heat dissipation duct, and a conical infrared guide section that covers the recess of the infrared radiation section with a bottom opening and connects the upper opening to a small hole in the partition wall, thereby reflecting and concentrating multiple far-infrared rays emitted from the radiation surface with its inner surface and guiding them to the end of the heat dissipation duct on the side of the object to be cooled.

[0039] In this case, although an infrared radiator with a heat collector is positioned on the cooling target side of the small hole that emits far-infrared rays into the external space, this small hole is located on or near the far-infrared radiating point, which is spaced apart from the infrared radiating point. Therefore, heat inflow from the external space through the small hole and sunlight irradiation through the small hole can be prevented from reaching the infrared radiating point, thereby lowering the temperature reached by the infrared radiating point during radiative cooling and ensuring high cooling efficiency.

[0040] Furthermore, the temperature rise suppression structure has an infrared radiation section with a roughly hemispherical radiation surface in which the recess faces the partition wall. This allows for the concentration of far-infrared radiation emitted from a wide-area radiation surface, increasing the energy density, reducing far-infrared radiation loss, and improving cooling efficiency.

[0041] Furthermore, the temperature rise suppression structure has a cylindrical heat dissipation duct that is inserted into a small hole, has an oblique cut at the tip on the external side, and reflects multiple far-infrared rays emitted from the radiating surface with its inner circumferential surface and releases them into the external space from the oblique cut. As a result, sunlight is reliably blocked by the side wall portion protruding from the oblique cut of the heat dissipation duct, and far-infrared rays are released into the external space through the heat dissipation duct by internal reflection even without parallelization. Therefore, large components such as shades for blocking sunlight and special components and structures such as plano-concave lenses for parallelizing infrared rays are unnecessary, which can reduce equipment costs and improve maintainability.

[0042] In addition, the temperature rise suppression structure has a far-infrared transparent duct insulation material fitted into the diagonally cut portion of the heat dissipation duct. As a result, far-infrared rays passing through the heat dissipation duct are transmitted through the transparent duct insulation material and released into the outside space, while heat from the outside space is blocked by the transparent duct insulation material. This further ensures that heat inflow from the outside space into the infrared radiation section through small holes is prevented.

[0043] Furthermore, the temperature rise suppression structure has a conical infrared guide section that covers the recess of the infrared radiation section with a bottom opening, while connecting the upper opening to a small hole in the partition wall. This section reflects and concentrates multiple far-infrared rays emitted from the radiation surface on its inner surface and guides them to the end on the cooling target side via a heat dissipation duct. This prevents multiple far-infrared rays emitted from the approximately hemispherical radiation surface from scattering far away from the concentration point and outside the radiative cooling device, and prevents the temperature of the infrared radiation section from rising due to far-infrared rays originating from fluids other than the cooling target being irradiated from the outside, thereby ensuring even higher cooling efficiency.

[0044] Further, in the present invention, the discharge portion is a small hole that penetrates the partition wall in the thickness direction with a smaller area than the infrared radiation portion, the infrared radiation portion is disposed on the cooling target side of the small hole, the temperature rise suppression structure includes an infrared radiation portion having a flat radiation surface facing the partition wall side, the small hole provided at a condensing portion of far infrared rays spaced apart from the infrared radiation portion, a cylindrical heat radiation duct that is inserted into the small hole and has an inclined cut portion provided at the tip on the external space side, and reflects a plurality of far infrared rays radiated from the radiation surface on the inner peripheral surface and discharges them from the inclined cut portion to the external space, a duct inner transparent heat insulating material having far infrared ray transmissivity and fitted to the inclined cut portion by the heat radiation duct, and while covering the flat portion of the infrared radiation portion with a bottom opening, connecting the upper opening to the small hole of the partition wall, and reflecting and condensing a plurality of far infrared rays radiated from the radiation surface on the inner peripheral surface, and guiding them to the end portion on the cooling target side by the heat radiation duct, and having a composite parabolic infrared guide portion.

[0045] In this case, although an infrared radiation portion with a heat collecting portion is disposed on the cooling target side of the small hole that discharges far infrared rays to the external space, since this small hole is provided at a condensing portion of far infrared rays spaced apart from the infrared radiation portion, it is possible to prevent heat inflow from the external space through the small hole and sunlight irradiation through the small hole to the infrared radiation portion, lower the reaching temperature of the infrared radiation portion during radiative cooling, and ensure high cooling efficiency.

[0046] And, since the temperature rise suppression structure has a cylindrical heat radiation duct that is inserted into the small hole and has an inclined cut portion provided at the tip on the external space side, and reflects a plurality of far infrared rays radiated from the radiation surface on the inner peripheral surface and discharges them from the inclined cut portion to the external space, sunlight is surely blocked by the side wall portion protruding at the inclined cut portion of the heat radiation duct, and far infrared rays are discharged to the external space through the heat radiation duct by internal reflection even without being parallelized. Therefore, large components such as shades for sunlight shielding and special components and structures such as plano-concave lenses for infrared parallelization are not required, and it is possible to reduce the device cost and improve the maintainability.

[0047] Furthermore, since the temperature rise suppression structure has a duct inner transparent heat insulating material with far-infrared ray transmissivity that is fitted into the diagonal cut portion of the heat radiation duct, far-infrared rays passing through the heat radiation duct pass through the duct inner transparent heat insulating material and are released into the external space. On the other hand, heat from the external space is blocked by the duct inner transparent heat insulating material, and heat inflow from the external space to the infrared ray radiation portion through the small holes can be more reliably prevented.

[0048] In addition, the temperature rise suppression structure covers the flat portion of the infrared ray radiation portion with the bottom opening, and connects the upper opening to the small holes of the partition wall, so that a plurality of far-infrared rays radiated from the radiation surface are reflected and condensed on the inner peripheral surface, and guided to the end on the cooling target side by the heat radiation duct. Since it has a compound parabolic infrared ray guide portion, many of the plurality of far-infrared rays radiated from the flat radiation surface can be surely guided to the end on the cooling target side by the inner peripheral surface of the compound parabola with high condensing performance. At the same time, it is possible to prevent far-infrared rays from scattering outside the radiation cooling device and far-infrared rays from a fluid source other than the cooling target from being irradiated from the outside and causing the temperature of the infrared ray radiation portion to rise, and a higher cooling efficiency can be ensured. Moreover, there is no need to configure the infrared ray radiation portion in a substantially hemispherical shape to enhance the condensing performance. Not only the infrared ray radiation portion, but also the heat receiving fins of the heat collecting portion implanted on the heat receiving surface can have a simple structure, and the device cost can be reduced and the maintainability can be further improved.

[0049] In addition, in the present invention, the heat collection promotion structure forms a heat receiving surface into which heat from the heat generating body flows inside a housing that surrounds the heat generating body of the cooling target, and has the infrared ray radiation portion configured to form the radiation surface outside the housing.

[0050] In this case, since the heat generating body is surrounded by the housing, after forming a radiation surface on the existing housing by applying a black film or the like, the present invention's radiation cooling device can be attached as a retrofit, and most of the heat from the heat generating body can be made to flow into the heat receiving surface and radiate from the radiation surface without escaping. As a result, many components such as heat receiving fins and a complicated structure are not required, and the device cost can be reduced and the maintainability can be improved. Also, when the existing cooling system alone cannot sufficiently cool, it can be additionally introduced to improve the cooling capacity.

[0051] Furthermore, the present invention provides a structure in which the emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, the infrared radiation portion is positioned on the cooling target side of the small hole, the temperature rise suppression structure comprises a conical or composite parabolic concentrator with a bottom opening covering the radiation surface of the infrared radiation portion, which concentrates far-infrared rays emitted from the radiation surface to the vicinity of its apex either directly or by internal reflection, an optical fiber portion in which one end of an optical fiber is connected to the apex of the concentrator and the other end of the optical fiber is gathered to form an insulating optical fiber bundle, and the small hole is located spaced apart from the infrared radiation portion, with the concentrator and optical fiber portion in between, and through the inserted optical fiber bundle, the concentrated far-infrared rays are emitted into the external space.

[0052] In this case, although an infrared radiation section with a heat collection promotion structure is placed on the cooling target side of the small hole that emits far-infrared rays into the external space, this small hole is positioned at a distance from the infrared radiation section, separated by a concentrator and optical fiber section. Therefore, heat inflow from the external space through the small hole and sunlight irradiation through the small hole can be prevented from reaching the infrared radiation section, thereby lowering the temperature reached by the infrared radiation section during radiative cooling and ensuring high cooling efficiency.

[0053] Furthermore, the temperature rise suppression structure has a bottom opening covering the radiating surface of the infrared radiation section, and includes a conical or composite parabolic concentrator that focuses the far-infrared rays emitted from the radiating surface either directly or through internal reflection to the vicinity of the apex, and an optical fiber section in which one end of an optical fiber is connected to the tip of the concentrator, and the other end of the optical fiber is gathered to form an insulating optical fiber bundle. By simply adjusting the length of the optical fibers or optical fiber bundle in the optical fiber section, the position of the small holes into which the optical fiber bundle is inserted can be freely changed, thereby more reliably preventing heat inflow from the external space through the small holes and sunlight irradiation through the small holes to the infrared radiation section.

[0054] Furthermore, even if some of the far-infrared radiation from the radiating surface undergoes repeated internal reflections without being focused near the apex of the concentrator, by optimizing the angle of incidence from the bottom opening and the shape of the inner surface, for example, by reducing the angle of incidence or by making the concentrator a composite parabolic surface and the inner surface a composite parabolic surface, the majority of it can ultimately be focused near the apex of the concentrator, thereby preventing a decrease in focusing performance.

[0055] Furthermore, even if the radiating surface has a shape that prevents the far-infrared rays from being focused in one place, such as a flat surface or a wavy curved surface, simply covering the radiating surface with the bottom openings of multiple concentrators allows the far-infrared rays emitted from the radiating surface within the bottom openings to be focused near the apex of each concentrator, then sent through each optical fiber to an optical fiber bundle, and finally emitted into the outside space through the small holes into which the optical fiber bundle is inserted. As a result, regardless of the shape of the radiating surface of the infrared radiating unit, the energy density can be increased by focusing the far-infrared rays emitted from a large-area radiating surface, and even with a compact device, the radiation loss of far-infrared rays can be reduced and the cooling efficiency can be improved.

[0056] Furthermore, the present invention provides a temperature rise suppression structure having a far-infrared transmitting convex lens between the radiating surface of the infrared radiation unit and the bottom opening of the light concentrator, which concentrates the far-infrared rays from the radiating surface to the top of the light concentrator.

[0057] In this case, by focusing most of the far-infrared radiation emitted from the radiating surface directly near the apex with a convex lens, scattering caused by internal reflection can be suppressed, reducing the scattering loss of far-infrared radiation and further improving cooling efficiency.

[0058] Furthermore, the present invention provides a radiator capable of emitting far-infrared rays with high emissivity at the end of the optical fiber section.

[0059] In this case, reducing the cross-sectional area of ​​the radiator can also reduce the size of the pores, making it possible to more reliably prevent heat inflow from the external space through the pores and to prevent sunlight irradiation.

[0060] According to the present invention, by providing an infrared radiation section with a heat collection promotion structure, heat from the object to be cooled can be efficiently collected in the infrared radiation section without the need for a special structure. Furthermore, by providing a temperature rise suppression structure that reliably prevents heat inflow from the external space and irradiation by sunlight into the infrared radiation section, the temperature reached by the infrared radiation section during radiative cooling can be lowered, ensuring high cooling efficiency even in various environments.

[0061] This is a partial cross-sectional view in plan showing the overall configuration of the radiative cooling device 1 according to the present invention. This is an enlarged partial cross-sectional view in plan showing the frame and its surroundings of the radiative cooling device 1. This is a partial cross-sectional view in side view showing the overall configuration of the radiative cooling device 1. This is a partial cross-sectional view in left-right direction showing the overall configuration of another form of radiative cooling device 1-a. This is a partial cross-sectional view in front-rear direction showing the overall configuration of another form of radiative cooling device 1-a. This is a partial cross-sectional view in left-right direction showing the overall configuration of another form of radiative cooling device 1-b. This is a partial cross-sectional view in front-rear direction showing the overall configuration of another form of radiative cooling device 1-b. This is a partial cross-sectional view in left-right direction showing the overall configuration of another form of radiative cooling device 1-c. This is a partial cross-sectional view in front-rearA. This is an enlarged partial cross-sectional view in plan showing the heat dissipation duct and its surroundings of the radiative cooling device 1A. This is a partial cross-sectional view in side view showing the overall configuration of another form of radiative cooling device 1A. This is a partial cross-sectional view in left-right direction showing the overall configuration of another form of radiative cooling device 1A-a. This is a partial cross-sectional view of the left-right side of a different radiative cooling device 1A-b, showing its overall configuration. This is a partial cross-sectional view of the top view of a different radiative cooling device 1B, showing its overall configuration. This is a magnified partial cross-sectional view of the top view of the concentrator and its surroundings in the same radiative cooling device 1B. This is a partial cross-sectional view of the side of a different radiative cooling device 1B, showing its overall configuration. This is a partial cross-sectional view of the top view of a different radiative cooling device 1B-a, showing its overall configuration. This is a magnified partial cross-sectional view of the top view of the concentrator with a convex lens and its surroundings in the same radiative cooling device 1B-a. This is a partial cross-sectional view of the left-right side of a different radiative cooling device 1B-b, showing its overall configuration.

[0062] The embodiments of the present invention relating to a radiative cooling device will be described below with reference to the drawings to facilitate understanding of the present invention. In Figures 1 and 2, the directions indicated by arrows L and R, and arrows I and O, respectively, are the left and right and inward and outward directions of the radiative cooling device relating to the present invention. In Figure 3, the directions indicated by arrows U and D are the up and down directions, and in Figure 5, the directions indicated by arrows F and B are the front and rear directions. The positions and directions of each component described below are based on these arrows L, R, I, O, U, D, F, and B.

[0063] First, the overall configuration of the radiative cooling device 1 to which the present invention is applied will be explained with reference to Figures 1 to 3.

[0064] The radiative cooling device 1 is attached to an insulating partition wall 11 that makes up the exterior wall, roof, etc. of a building 10 such as a house or factory building, and is placed in a fluid to be cooled, such as the high-temperature air inside the building 5 in summer. It is equipped with a heat collection unit 2 as a heat collection promotion structure 41a that promotes heat collection from the fluid, an infrared radiation unit 3 that radiates the heat flowing in from the heat collection unit 2 as far-infrared rays 29, an opening window 12 provided in the aforementioned partition wall 11 that is an emission unit that releases the far-infrared rays 29 from the infrared radiation unit 3 to the outside space, the outdoors 6, and a temperature rise suppression structure 4 that suppresses the temperature of the infrared radiation unit 3 from rising due to heat inflow from the outdoor air 6 or irradiation by sunlight 7.

[0065] The heat collection section 2 is composed of multiple plate-shaped heat receiving fins 8 of the same shape that are vertically installed and spaced approximately equally apart in the left-right direction. The inner part I of the heat collection section 2 is exposed to the inside of the building 5, while the outer part O of the heat collection section 2 has the outer ends of all of its heat receiving fins 8 embedded in the heat receiving surface 3a1 of the infrared radiation section 3.

[0066] By using multiple heat-receiving fins 8 arranged in this manner, the heat collection area is greatly expanded. As a result, a large amount of heat flows into the heat-receiving fins 8 that come into contact with the high-temperature air inside the building 5, and is conducted through the heat-receiving fins 8 to the heat-receiving surface 3a1 of the infrared radiation unit 3. Furthermore, due to temperature differences between the heat-receiving fins 8 and the surroundings, thermal convection occurs in the gaps between the heat-receiving fins 8, and as it moves, it comes into direct contact with the heat-receiving surface 3a1 of the infrared radiation unit 3, and heat due to thermal convection also flows into the heat-receiving surface 3a1.

[0067] This allows the heat from the high-temperature air, which is the fluid to be cooled, to be efficiently collected in the infrared radiation unit 3 through thermal conduction and thermal convection.

[0068] Furthermore, the infrared radiation section 3 into which heat flows from the heat collection section 2 is a flat plate-shaped structure and consists of a substrate 3a having the aforementioned heat receiving surface 3a1 on its inner side I, and a black coating 3b formed on the coated surface 3a2 on the substrate 3a opposite to the heat receiving surface 3a1. The surface of this black coating 3b is the radiation surface 3b1 that emits far-infrared rays 29.

[0069] In this configuration, when heat from the heat collecting unit 2 flows from the heat receiving surface 3a1 to the substrate 3a, this heat is radiated from the radiating surface 3b1 of the black coating 3b on the coated surface 3a2 of the substrate 3a as far-infrared radiation 29 with a wavelength range of approximately 8 μm to 14 μm.

[0070] Of these, the substrate 3a is preferably made of a metal with high thermal conductivity, such as aluminum or copper. From the viewpoint of matching the thermal conductivity and improving heat transfer efficiency, the material of the heat receiving fins 8 that constitute the heat collecting section 2 is also preferably the same as that of the infrared radiating section 3.

[0071] Furthermore, the black coating 3b is preferably one that closely resembles a black body, such as one made by applying black paint spray or attaching black tape. The radiating surface 3b1 of such a black coating 3b can stably emit far-infrared rays 29 in the wavelength range of 8 μm to 14 μm as described above.

[0072] In this embodiment, the infrared radiation section 3 is a composite structure of a substrate 3a and a black coating 3b, with the surface of the black coating 3b serving as the radiation surface 3b1. However, it may also be a single structure made of a carbon material such as graphite, and the structure and material are not particularly limited as long as they have excellent thermal conductivity and high far-infrared radiation emissivity 29.

[0073] In addition, although the heat receiving fins 8 and the substrate 3a of the infrared radiation unit 3 are separate in this embodiment, they may be a single piece formed by casting or a single molded piece fastened together by welding or screws. As long as the heat receiving fins 8 and the substrate 3a are in thermal contact and the heat from the heat receiving fins 8 can be efficiently conducted to the substrate 3a, the connection method between the heat receiving fins 8 and the substrate 3a is not particularly limited.

[0074] Furthermore, the aforementioned opening window 12 has substantially the same shape and area as the infrared radiation unit 3, and is constructed by inserting a rectangular frame 13 into a rectangular opening 11a made in the partition wall 11.

[0075] The infrared radiation unit 3 is then fitted into the stepped portion 12a formed by the inner end surface 13a of the inner part I and the inner circumferential surface 11a1 of the opening 11a within the frame 13, thereby covering the inner part I, which is the cooling target side of the opening window 12.

[0076] Furthermore, in the aforementioned temperature rise suppression structure 4, a rectangular transparent window insulation material 14 is fitted inside the frame 13 of the opening window 12 on the outer side O, which is on the side of the infrared radiation part 3 that is in the external space.

[0077] The transparent insulation material 14 inside the window can be vacuum glass, which has a vacuum in the air gap between two transparent panes of glass, or double-glazed glass in which an inert gas such as dry air or argon gas is sealed in the air gap between two or three transparent panes of glass. However, as for the glass, quartz glass, germanium glass, chalcogenide glass, etc., are used because they have excellent far-infrared transmission properties.

[0078] As a result, the far-infrared rays 29 emitted from the radiating surface 3b1 of the infrared radiation unit 3 are transmitted through the transparent insulating material 14 inside the opening window 12 and released into the outdoor space 6, while heat from the outdoor space 6 can be blocked by the transparent insulating material 14 inside the window.

[0079] Furthermore, the aforementioned opening window 12 has a U-shaped shade 15 that opens downward when viewed from the side, which protrudes from the outer surface of the frame 13 toward the outside O, which is the external space.

[0080] As a result, far-infrared rays 29 pass through the opening window 12 and through the transparent insulation material 14 inside the window and are emitted into the outdoor space 6, while sunlight 7 can be reliably blocked by the shade 15.

[0081] This U-shaped shade 15 consists of an upper plate 15a covering the upper U, a left plate 15b covering the left L, and a right plate 15c covering the right R. In this embodiment, the maximum projection height outward O of all three plates is the same, but more specifically, it is preferable that the projection height outward O of the upper plate 15a is set to the height that blocks sunlight 7 at noon on the summer solstice, calculated from the latitude of the location where the radiative cooling device 1 is installed, and that the projection heights outward O of the left plate 15b and right plate 15c are set to the height that blocks sunlight 7 at sunrise and sunset on the summer solstice, calculated from the latitude of the location where the radiative cooling device 1 is installed.

[0082] The inner surfaces 15a2, 15b2, and 15c2 of the top plate 15a, left plate 15b, and right plate 15c that make up the shade 15 are covered with reflective materials such as aluminum and silver, or are plated with metals such as chromium and nickel, or subjected to mirror polishing or mirror finishing to form reflective surfaces. As a result, most of the far-infrared rays 29 from the infrared radiation unit 3 are reflected by the inner surfaces 15a2, 15b2, and 15c2 of the shade 15 without being absorbed, and released into the outdoor space 6, thereby further improving cooling efficiency.

[0083] The outer surfaces of the aforementioned top plate 15a, left plate 15b, and right plate 15c may be coated with heat-shielding paint, or insulation material may be used on the top plate 15a, left plate 15b, and right plate 15c themselves. This suppresses the temperature rise of the inner surfaces 15a2, 15b2, and 15c2, and prevents the temperature of the infrared radiation section 3 from rising due to the far-infrared rays 29 emitted from these inner surfaces 15a2, 15b2, and 15c2 being irradiated through the opening window 12.

[0084] Alternatively, by attaching film-type solar cells to the outer surfaces of the top plate 15a, left plate 15b, and right plate 15c, or by installing a solar panel 9, as described later, on the top plate 15a, which has a longer period of sunlight, solar power generation can also be used in combination. This configuration allows switching between radiative cooling and electric cooling depending on the object to be cooled and the sunlight conditions, thereby further improving cooling efficiency.

[0085] In addition, a detachable structure 16 for incorporating the shade 15 in a replaceable manner is provided on the frame 13.

[0086] In this detachable structure 16, the inner edges I of the upper plate 15a, left plate 15b, and right plate 15c are bent outward and protrude at a right angle to form protruding edges 15a1, 15b1, and 15c1, and multiple through holes 15d are drilled in these protruding edges 15a1, 15b1, and 15c1. Then, bolt holes 13b are screwed into the frame 13 at the positions of the through holes 15d of the shade 15 that is in contact with it.

[0087] In this state, the shade 15 can be detachably fastened and fixed to the frame 13 by inserting multiple bolts 17 vertically through the through holes 15d of the protruding edges 15a1, 15b1, and 15c1, and then screwing them into the bolt holes 13b of the frame 13.

[0088] This allows for the interchangeable incorporation of shades 15 optimized according to the installation conditions of the opening window 12, and enables flexible adaptation even if the installation position or orientation of the opening window 12 changes, simply by changing the size and shape of the shade 15.

[0089] In other words, it includes a heat collection promotion structure 41a that promotes heat collection from the high-temperature air inside the building 5 which is to be cooled; an infrared radiation section 3 in which heat flows into the heat receiving surface 3a1 by the heat collection promotion structure 41a, while the incoming heat is radiated as far-infrared rays 29 from the radiating surface 3b1 opposite to the heat receiving surface 3a1; an opening window 12 which is an emission section provided in the partition wall 11 that separates the infrared radiation section 3 from the outdoor space 6 and emits the far-infrared rays 29 from the radiating surface 3b1 into the outdoor space 6; and a temperature rise suppression structure 4 between the radiating surface 3b1 and the outdoor space 6, which prevents heat from flowing into the infrared radiation section 3 from the outdoor space 6 through the opening window 12 and irradiation by sunlight 7, thereby suppressing the temperature rise of the infrared radiation section 3.

[0090] Furthermore, a heat collection promotion structure 41a is provided to facilitate heat collection from high-temperature air. By using this heat collection promotion structure 41a to allow heat to flow into the heat receiving surface 3a1 of the infrared radiation unit 3, heat from high-temperature air can be efficiently collected by the infrared radiation unit 3.

[0091] Furthermore, by providing a temperature rise suppression structure 4 between the radiating surface 3b1 of the infrared radiating unit 3 and the outdoors 6, which reliably prevents heat inflow from outdoors 6 to the infrared radiating unit 3 via the opening window 12 and irradiation by sunlight 7, the temperature rise of the infrared radiating unit 3 is suppressed, the temperature reached by the infrared radiating unit 3 during radiative cooling is lowered, and high cooling efficiency can be ensured even in various environments.

[0092] Furthermore, if such a heat collection promoting structure 41a has a heat collection section 2 comprising plate-shaped heat receiving fins 8 embedded in the heat receiving surface 3a1 and arranged in high-temperature air, the heat collection area can be expanded by using multiple heat receiving fins 8 arranged in a row, and the generation of thermal convection can be promoted due to temperature differences between the heat receiving fins 8 and the surroundings. This allows heat from high-temperature air to be collected more efficiently into the infrared radiation section 3 by thermal conduction and thermal convection without the need for a special structure.

[0093] Furthermore, if the aforementioned emission section is an opening window 12 that opens into the partition wall 11 to substantially the same shape and area as the infrared radiation section 3, and the infrared radiation section 3 is installed on the inner side I of the opening window 12 which is the side to be cooled, and the temperature rise suppression structure 4 has a far-infrared transparent window insulation material 14 fitted to the outer side O of the opening window 12 which is on the external space side of the infrared radiation section 3, a shade 15 erected on the outer side O of the opening window 12 to block sunlight 7, and a detachable structure 16 that incorporates a replaceable shade 15 optimized according to the installation conditions of the opening window 12, then in an opening window 12 that emits far-infrared rays 29 to the outdoors 6, an infrared radiation section 3 with a heat collection section 2 is installed on the inner side I, and the window insulation material 14 and shade 15 are attached to the opposite side, it is possible to provide a highly versatile radiative cooling device 1 that can handle radiative cooling of objects of various sizes and temperatures.

[0094] Furthermore, the temperature rise suppression structure 4 has a far-infrared transparent window insulation material 14 fitted to the outside O of the opening window 12, which is on the external space side of the infrared radiation unit 3. As a result, the far-infrared rays 29 emitted from the radiation surface 3b1 of the infrared radiation unit 3 pass through the window insulation material 14 of the opening window 12 and are released to the outside 6, while heat from the outside 6 is blocked by the window insulation material 14, preventing heat from flowing into the infrared radiation unit 3.

[0095] Furthermore, since the temperature rise suppression structure 4 has a shade 15 erected outside O of the opening window 12 to block sunlight 7, as described above, far-infrared rays 29 pass through the opening window 12 and through the transparent insulation material 14 inside the window and are emitted to the outdoors 6, while sunlight 7 is reliably blocked by the shade 15, preventing sunlight from irradiating the infrared radiation part 3 through the transparent insulation material 14 inside the window and the opening window 12.

[0096] In addition, the temperature rise suppression structure 4 has a removable structure 16 that allows for the replacement of a shade 15 optimized according to the installation conditions of the opening window 12. Therefore, even if the installation position or orientation of the opening window 12 changes, it can be accommodated simply by changing the size and shape of the shade 15, thereby reducing equipment costs and improving maintainability.

[0097] Next, radiative cooling devices 1-a, 1-b, and 1-c, which are alternative forms of the aforementioned radiative cooling device 1, will be explained with reference to Figures 4 to 9.

[0098] As shown in Figures 4 to 9, in all of these radiative cooling devices 1-a, 1-b, and 1-c, the object to be cooled is not the high-temperature air of radiative cooling device 1, but the cooling water 45 in the water tank 43, which has an upper opening attached to the partition plate 11 mentioned above.

[0099] The cooling water 45 is poured in through an inlet pipe 46 located at the top of the front side plate 43a of the water tank 43 and discharged through an outlet pipe 47 located at the bottom of the rear side plate 43b of the water tank 43. These inlet pipe 46 and outlet pipe 47 are connected via piping 49 to a heat exchanger 48 incorporated into cooling equipment, air conditioning equipment, prime movers, etc.

[0100] As a result, the cooling water 45 whose temperature has risen in the heat exchanger 48 flows into the water tank 43 through the piping 49 and the inlet pipe 46, is cooled by the heat collector 52, becomes cooling water whose temperature has decreased again, and is supplied to the heat exchanger 48 through the outlet pipe 47 and the piping 49, thereby forming a cooling circuit 35.

[0101] The heat collection section 52 is similar to the heat collection section 2 of the radiative cooling device 1, and consists of multiple vertically mounted heat receiving fins 8 of the same shape, spaced approximately equally apart in the left-right direction within the cooling water 45 to be cooled. The heat collection promotion structure 41b is provided with such a heat collection section 52.

[0102] The infrared radiation unit 53 is similar to the infrared radiation unit 3 of the radiative cooling device 1, and is a flat plate shape, consisting of a substrate 53a having a heat receiving surface 53a1 on its inner side I to which the outer ends of the aforementioned heat receiving fins 8 are implanted, and a black coating 53b formed on this substrate 53a, the surface of which the black coating 53b becomes a radiation surface 53b1 that emits far-infrared rays 29.

[0103] The opening window 59 is similar to the opening window 12 of the radiative cooling device 1, and has substantially the same shape and area as the infrared radiation unit 53 described above. It is constructed by inserting a rectangular frame 50 into a rectangular opening 11a made in the partition wall 11. The infrared radiation unit 53 is covered on the lower surface of this frame 50.

[0104] The temperature rise suppression structures 51a, 51b, and 51c also have, similar to the transparent window insulation material 14 of the radiative cooling device 1, a rectangular transparent window insulation material 54 fitted to the outer side O of the opening window 59, which is on the side of the infrared radiation section 53 that is in the external space, and a shade 55 erected on the outdoor side 6 of the opening window 59 to block sunlight, similar to the shade 15 of the radiative cooling device 1. However, apart from these, they differ from the radiative cooling device 1 in that they are newly provided with switching mechanisms 60a, 60b, and 60c that can switch between a state where sunlight is transmitted and a state where it is blocked.

[0105] As a result, during the day, even sunlight that cannot be blocked by the shade 55 is reliably blocked by the switching mechanisms 60a, 60b, and 60c, and only at night when there is no sunlight 7, the switching mechanisms 60a, 60b, and 60c allow light to pass through, so that far-infrared rays 29 can be emitted to the outdoors 6. At this time, by providing the shade 55, it is possible to prevent sunlight 7 from mistakenly irradiating the infrared radiation unit 53 during the transition between day and night.

[0106] Here, the transparent insulation material 54 inside the window is made of a single piece of glass with excellent far-infrared transmittance, but it may also be double-glazed glass like the transparent insulation material 14 inside the window mentioned above, and is not particularly limited as long as it has excellent far-infrared transmittance.

[0107] As a result, the far-infrared rays 29 emitted from the radiating surface 53b1 of the infrared radiating unit 53 are transmitted through the transparent insulating material 54 inside the opening window 59 and released to the outdoors 6, while heat from the outdoors 6 can be blocked by the transparent insulating material 54 inside the window.

[0108] In other words, the emission section is an opening window 59 that opens into the partition wall 11 to be substantially the same shape and area as the infrared radiation section 53, the infrared radiation section 53 is covered on the inner side I of the opening window 59 which is the side to be cooled, and the temperature rise suppression structures 51a, 51b, and 51c are a far-infrared transparent window insulation material 54 fitted to the outer side O of the opening window 59 which is on the external space side than the infrared radiation section 53, a shade 55 erected on the outer side O of the opening window 59 which is the external space side to block sunlight, and sunlight 7 When a switching mechanism 60a, 60b, 60c is provided that can switch between a light-transmitting state and a light-blocking state, a radiant cooling device 1-a, 1-b, 1-c can be provided with a simple configuration in which an infrared radiation unit 53 with a heat-collecting unit 52 is installed on the inside I of an opening window 59 that emits far-infrared rays 29 to the outside 6, and a transparent insulating material 54 or shade 55 is attached to the opposite side of the window, and it can handle radiant cooling of objects of various sizes and temperatures, thus providing a highly versatile radiant cooling device 1-a, 1-b, 1-c.

[0109] Furthermore, since the temperature rise suppression structures 51a, 51b, and 51c have a far-infrared transparent window insulation material 54 fitted in the opening window 59 outward from the infrared radiation section 53, the far-infrared rays 29 emitted from the radiation surface 53b1 of the infrared radiation section 53 are transmitted through the window insulation material 54 of the opening window 59 and released to the outdoors 6, while heat from the outdoors 6 is blocked by the window insulation material 54, preventing heat from flowing into the infrared radiation section 53.

[0110] Furthermore, since the temperature rise suppression structures 51a, 51b, and 51c have shades 55 erected outside O of the opening window 59 to block sunlight 7, as described above, far-infrared rays 29 pass through the opening window 59 and through the transparent insulation material 54 inside the window and are emitted to the outdoors 6, while sunlight 7 is blocked by the shades 55, preventing sunlight from irradiating the infrared radiation section 53 through the transparent insulation material 54 inside the window and the opening window 59.

[0111] In addition, the temperature rise suppression structures 51a, 51b, and 51c have switching mechanisms 60a, 60b, and 60c that can switch between a state in which sunlight 7 is transmitted and a state in which it is blocked. Therefore, during the day, sunlight 7 is reliably blocked, and only at night when there is no sunlight 7 is emitted to the outdoors 6, thereby more reliably preventing sunlight irradiation of the infrared radiation unit 53.

[0112] Furthermore, as shown in Figures 4 and 5, in the radiative cooling device 1-a, the aforementioned transparent insulation material 54 inside the window is fitted into an L-shaped groove 50a in cross-section provided on the inner circumferential surface of the upper end of the frame 50, and a switching mechanism 60a having a dimming panel 61 is arranged inside the frame 50 between the transparent insulation material 54 inside the window and the infrared radiation unit 53.

[0113] The dimming panel 61 has substantially the same shape and area as the transparent insulation material 54 inside the window, and is a thin plate shape with no movable parts and requiring a small installation space. Its outer edge is fitted into a U-shaped groove 50b provided on the inner surface of the frame 50 approximately in the upper and lower center.

[0114] Here, the dimming panel 61 is a dimming sheet mounted on a transparent substrate such as a glass substrate with excellent far-infrared transmittance, and is composed of, for example, a dimming layer containing a liquid crystal composition such as a polymer-dispersed liquid crystal, and a pair of electrode sheets sandwiching this dimming layer.

[0115] Furthermore, the electrode sheet consists of a transparent electrode layer supported by a transparent support layer. When operating power is supplied between this pair of transparent electrode layers, the light distribution state of the liquid crystal compound in the dimming layer changes according to the voltage. This allows for switching between a transparent state in which light passes through the aforementioned dimming layer and an opaque state in which light transmission in the dimming layer is suppressed by scattering or other means.

[0116] As a result, the dimming panel 61 can also switch between a transparent state and an opaque state, that is, between a state where sunlight 7 is transmitted and a state where it is blocked, depending on whether or not operating power is supplied.

[0117] Furthermore, a control device 56 with a program timer function that can automatically switch electrical equipment on and off at specific times is mounted and fixed on the partition wall 11 near the frame 50, and a solar panel 57 that supplies operating power for switching between a light-transmitting state and a light-blocking state is installed between this control device 56 and the aforementioned frame 50.

[0118] Here, the control device 56 has a battery 56b for storing operating power and a control unit 56a for controlling the power supply timing for supplying operating power to the switching mechanisms 60a, 60b, and 60c. The aforementioned solar panel 57 and battery 56b are connected to this control unit 56a, and it is also connected to the aforementioned dimming panel 61 via wiring 58. The power supply device 62 is composed of these solar panel 57, control unit 56a, battery 56b, etc.

[0119] As a result, during the day, the solar panel 57 receives sunlight 7 and generates electricity. The generated electricity is supplied by the control unit 56a to the dimming panel 61 as operating power, causing the dimming panel 61 to become opaque. At the same time, a portion of the electricity is used to charge the battery 56b.

[0120] At night, when there is no sunlight 7, the solar panel 57 does not generate electricity, so no power is supplied to the dimming panel 61, and the dimming panel 61 becomes transparent. Under conditions where there is no sunlight irradiating the infrared radiation section 53, the far-infrared rays 29 from the far-infrared radiation section 53 can be transmitted through the transparent insulation material 54 inside the window from the dimming panel 61 and emitted into the outdoor space 6.

[0121] However, even during the daytime, if the intensity of sunlight 7 is weak and sufficient operating power is not generated, the program timer function of the control unit 56a can automatically supply operating power from the battery 56b to the dimming panel 61 at a specific time.

[0122] This configuration allows for flexible determination of the power supply timing, which automatically switches between day and night, based on the intensity of sunlight and the set time.

[0123] In other words, if the switching mechanism 60a has a dimming panel 61 that can automatically switch between a transparent state in which sunlight 7 is transmitted and an opaque state in which the transmission of sunlight 7 is blocked, the dimming panel 61 is a thin plate shape with no movable parts and does not require a large installation space, so it can be installed in the narrow space between the infrared radiation unit 53 and the transparent insulation material 54 inside the window, and the radiative cooling device 1-a can be made more compact by miniaturizing the opening window 59 which is the emission unit.

[0124] Furthermore, if the switching mechanism 60a is equipped with a power supply device 62 which includes a solar panel 57 that supplies operating power for switching between a light-transmitting state and a light-blocking state, a battery 56b that stores the operating power, and a control unit 56a that controls the timing of power supply to the switching mechanism 60a, then periodic battery replacement and manual switching operations become unnecessary, improving maintenance and reducing the workload. In addition, the accuracy of switching between the light-transmitting state and the light-blocking state of the sunlight 7 is improved, making it possible to more reliably prevent sunlight from irradiating the infrared radiation unit 53.

[0125] Furthermore, as shown in Figures 6 and 7, in the radiative cooling device 1-b, unlike the radiative cooling device 1-a, the transparent insulation material 54 inside the window is fitted into a U-shaped groove 50c provided on the inner circumferential surface approximately in the upper and lower center of the frame 50, and is positioned inside the frame 50.

[0126] A shutter frame 63 is fitted onto the lower outer surface 55b of the shade 55, which is erected on the upper surface 50d of the frame 50. Within this shutter frame 63, four rotating shafts 65 are pivotally supported between the left and right side plates 55c and 55d of the shade 55, spaced approximately equally apart in the front-to-back direction.

[0127] The center of the long plate-shaped shutter body 64 in the width direction is fixed to these rotating shafts 65, and the switching mechanism 60b having these shutter bodies 64 is arranged inside the shutter frame 63.

[0128] The shutter body 64 is a thin plate shape that rotates together with the rotation shaft 65, and since a large space is required for its rotation, the transparent insulation material 54 inside the window is housed within the frame 50, and the shutter body 64 is housed within the shutter frame 63 above it.

[0129] The material of such a shutter body 64 is not particularly limited as long as it blocks sunlight, but it is preferable that, similar to the shades 15 and 55 mentioned above, it can be used to prevent temperature rise by attaching a reflective material such as aluminum or silver to the surface to form a reflective surface, or by applying a heat-shielding paint to the surface.

[0130] On the other hand, in the notch on the right side of the shutter frame 63, the shutter drive device 67 is fitted into the stepped portion formed by the upper surface 50d of the frame 50 and the outer surface 55b of the shade 55.

[0131] This shutter drive device 67 has a simple configuration that only incorporates an electric motor 67a. The output shaft 67a1 of this electric motor 67a is connected to the rotation shaft 65 of the shutter body 64, and the rotation angle of the shutter body 64 can be freely adjusted by the rotation of the rotation shaft 65 by the electric motor 67a.

[0132] This allows the rotation shaft 65 to be rotated by supplying operating power to the electric motor 67a, and the rotation position of the shutter body 64 can be freely changed between a closed position 66a, in which the opening window 59 is closed, and an open position 66b, in which the opening window 59 is open.

[0133] Furthermore, the front end of the solar panel 57, which constitutes the aforementioned power supply device 62, is mounted and fixed on the shutter drive device 67, and the control unit 56a of the control device 56, which constitutes the power supply device 62, is connected to the electric motor 67a of the shutter drive device 67 via wiring 68.

[0134] As a result, during the day, the solar panel 57 receives sunlight 7 and generates electricity. The generated electricity is supplied by the control unit 56a to the electric motor 67a of the shutter drive device 67 as operating power, causing all four shutter bodies 64 to rotate to the closed position 66a, closing the opening window 59 and blocking sunlight 7. At the same time, a portion of the electricity is charged into the battery 56b.

[0135] At night, when there is no sunlight 7, the solar panel 57 does not generate electricity, so the control unit 56a determines that it is nighttime, and operating power is automatically supplied from the battery 56b to the electric motor 67a, causing all four shutter bodies 64 to rotate to the open position 66b, the opening window 59 to open, and under conditions where there is no sunlight irradiating the infrared radiation unit 53, far-infrared rays 29 from the far-infrared radiation unit 53 can be emitted from the transparent insulation material 54 inside the window to the outside space, which is the outdoors 6.

[0136] However, even during the daytime, if the intensity of sunlight 7 is weak and sufficient operating power is not generated, the program timer function of the control unit 56a can automatically supply operating power from the battery 56b to the electric motor 67a at a specific time.

[0137] In other words, if the switching mechanism 60b has a shutter body 64 that can automatically switch between an open state and a closed state of the opening window 59 between day and night by a rotational operation by an electric motor 67a, the shutter drive device 67, which is an opening and closing device that opens and closes the opening window 59 by rotating or sliding the shutter body 64, has a simple configuration and the materials of its components can be inexpensive, thus reducing the cost of the device and improving maintainability.

[0138] Furthermore, as shown in Figures 8 and 9, in the radiative cooling device 1-c, the transparent insulation material 54 inside the window is fitted into a U-shaped groove 50c provided on the inner circumferential surface approximately in the upper and lower center of the frame 50, similar to the radiative cooling device 1-b, and is positioned within the frame 50.

[0139] A curtain frame 73 is fitted onto the lower outer surface 55b of the shade 55, which is erected on the upper surface 50d of the frame 50. Within this curtain frame 73, a light-blocking curtain 74 is positioned approximately horizontally between the left and right side plates 55c and 55d of the shade 55.

[0140] Within the curtain frame 73, front and rear guide rails 71 and 72, which are U-shaped in cross-section and open inward, are fixed to the inside of the front and rear side plates 55e and 55f of the shade 55. The front and rear edges of the light-blocking curtain 74 are inserted into the grooves of these guide rails 71 and 72, allowing them to slide. A switching mechanism 60c having this light-blocking curtain 74 is located within the curtain frame 73.

[0141] The light-blocking curtain 74 is a thin plate that can be wound up and unwound by an electric motor 77a, which will be described later. Its material is not particularly limited as long as it blocks sunlight, but it is preferable that, like the shades 15 and 55 and the shutter body 64 described above, it can be made to form a reflective surface by attaching a reflective material such as aluminum or silver to its surface, or to apply a heat-shielding paint to its surface to prevent temperature rise.

[0142] On the other hand, in the notch on the right side of the curtain frame 73, the light-blocking curtain drive device 77 is fitted into the stepped portion formed by the upper surface 50d of the frame 50 and the outer surface 55b of the shade 55.

[0143] This light-blocking curtain drive device 77 has a simple configuration that only incorporates an electric motor 77a. The output shaft 77a1 of this electric motor 77a is connected to the right edge of the light-blocking curtain 74. By rotating the output shaft 77a1 with the electric motor 77a, the light-blocking curtain 74 can be wound onto the output shaft 77a1 or unwound from the output shaft 77a1 while sliding within the front and rear guide rails 71 and 72.

[0144] Furthermore, similar to the radiative cooling device 1-b, the front end of the solar panel 57 that constitutes the power supply device 62 is mounted and fixed on the light-shielding curtain drive device 77, and the control unit 56a of the control device 56 that constitutes the power supply device 62 is connected to the electric motor 77a of the light-shielding curtain drive device 77 via wiring 78.

[0145] As a result, during the day, power from the solar panel 57 is supplied as operating power to the electric motor 77a of the shading curtain drive device 77 by the control unit 56a, causing the shading curtain 74 to extend until its left end hits the left side plate 55c of the shade, closing the opening window 59 and blocking sunlight 7, while simultaneously charging the battery 56b with some of the power.

[0146] At night, when there is no sunlight 7, the solar panel 57 does not generate power, so the control unit 56a determines that it is nighttime, and operating power is automatically supplied from the battery 56b to the electric motor 77a, the left end of the light-blocking curtain 74 is rolled up to the right side plate 55d of the shade, the opening window 59 is opened, and under conditions where there is no sunlight irradiating the infrared radiation unit 53 at all, far-infrared rays 29 from the far-infrared radiation unit 53 can be emitted from the transparent insulation material 54 inside the window to the outside space, which is the outdoors 6.

[0147] However, even during the daytime, if the intensity of sunlight 7 is weak and sufficient operating power is not generated, the program timer function of the control unit 56a can automatically supply operating power from the battery 56b to the electric motor 77a at a specific time.

[0148] In other words, if the switching mechanism 60c has a light-shielding curtain 74 that can automatically switch between an open state and a closed state of the opening window 59 between day and night by winding and unwinding operations, the light-shielding curtain drive device 77, which is an opening and closing device that opens and closes the opening window 59 by winding and unwinding the light-shielding curtain 74, has a simple configuration and the materials of its components can be inexpensive, thus reducing the cost of the device and improving maintainability.

[0149] Next, a different form of the radiative cooling device 1 described above, radiative cooling device 1A, will be explained with reference to Figures 10 to 12.

[0150] Unlike the opening window 12 in the radiative cooling device 1, which has substantially the same shape and area as the infrared radiation section 3, the emission section of this radiative cooling device 1A is a small hole 11b with a smaller area than the infrared radiation section 23, and is formed to penetrate the partition wall 11 in the thickness direction.

[0151] Then, the far-infrared rays 29 from the infrared radiation unit 23 located on the inner side I of the small hole 11b, which is the side to be cooled, are emitted through the small hole 11b to the outdoor space 6.

[0152] Furthermore, the shape of this infrared radiation unit 23 differs from that of the infrared radiation unit 3 of the radiative cooling device 1, being a roughly hemispherical shape with a recess 23c facing the partition wall 11. However, its structure is the same as that of the infrared radiation unit 3, consisting of a substrate 23a having a convex heat-receiving surface 23a1 on its inner side I, and a black coating 23b formed on the concave coated surface 23a2 on the substrate 23a opposite to the heat-receiving surface 23a1. The surface of this black coating 23b is the radiation surface 23b1 that emits far-infrared rays 29.

[0153] Furthermore, since this radiating surface 23b1 is also roughly hemispherical, the far-infrared rays 29 emitted from the radiating surface 23b1 are focused at the center of the hemisphere spaced apart from the infrared radiating section 23, more specifically at a focal point 20 corresponding to the center of the sphere containing the roughly hemispherical radiating surface 23b1, and the aforementioned small hole 11b is provided on this focal point 20.

[0154] In this way, since the small holes 11b are provided at a distance from the infrared radiation unit 23, it is possible to prevent heat from flowing into the infrared radiation unit 23 from the outdoor space 6 through the small holes 11b and to prevent sunlight irradiation through the small holes 11b.

[0155] Furthermore, since the infrared radiation unit 23 has such a roughly hemispherical radiation surface 23b1, it is possible to concentrate the far-infrared rays 29 emitted from the wide-area radiation surface 23b1 to increase the energy density and reduce radiation loss of the far-infrared rays 29.

[0156] Furthermore, the structure of the heat collection unit 22 attached to the infrared radiation unit 23 is the same as that of the heat collection unit 2 of the radiative cooling device 1, and consists of a plurality of vertically installed heat receiving fins 28 arranged at approximately equal intervals in the left-right direction. The inner part I of the heat collection unit 22 is exposed to the inside of the building 5, while the outer part O of the heat collection unit 22 has the outer ends of all of its heat receiving fins 28 embedded in the heat receiving surface 23a1 of the infrared radiation unit 23, and a heat collection promotion structure 41c having such a heat collection unit 22 is provided.

[0157] However, unlike the uniform rectangular heat receiving fins 8 in the heat collection section 2, the shape of the heat receiving fins 28 differs in that the outer edge 28a on the infrared radiation section 23 side is formed along the convex heat receiving surface 23a1. As a result, the shape of the outer edge 28a changes from a straight section to a concave section as it approaches the center from the left and right ends. This makes it possible to reduce the total area of ​​the heat receiving fins 28, which in turn makes the heat collection section 22 lighter and improves the ease of assembly of the radiative cooling device 1A.

[0158] In this heat collection unit 22, as in the heat collection unit 2 described above, the heat collection area is greatly expanded by using multiple heat receiving fins 28, allowing a large amount of heat to flow in. Heat also flows in through thermal convection in the gaps between the heat receiving fins 28, and the heat from the high-temperature air, which is the fluid to be cooled, can be efficiently collected in the infrared radiation unit 23 by thermal conduction and thermal convection.

[0159] Furthermore, a cylindrical heat dissipation duct 25 is inserted and fixed into the aforementioned small hole 11b. A far-infrared transparent plano-concave lens 26 is fitted to the inner end I of this heat dissipation duct 25. Multiple far-infrared rays 29 from the approximately hemispherical radiating surface 23b1 enter the heat dissipation duct 25 so as to be focused at the aforementioned focal point 20. As they pass through the plano-concave lens 26, they become parallelized and pass through the heat dissipation duct 25 along its axis.

[0160] This allows the focused far-infrared rays 29 to be converted into parallel light, pass through the heat dissipation duct 25 without scattering inside, and be emitted to the outdoors 6. This reduces the scattering loss of far-infrared rays 29 and also prevents the backflow of heat to the infrared radiation unit 23 due to diffuse reflection during scattering.

[0161] Furthermore, a transparent duct insulation material 27 made of double-glazed glass that transmits far infrared rays is fitted to the end of the heat dissipation duct 25 that is outward O from the plano-concave lens 26. As described above, the far infrared rays 29 that are parallelized by the plano-concave lens 26 pass through the heat dissipation duct 25 and through the transparent duct insulation material 27 to be released to the outdoors 6, while heat from the outdoors 6 is blocked by this transparent duct insulation material 27.

[0162] This makes it possible to more reliably prevent heat from flowing from the outdoor space 6 to the infrared radiation unit 23 through the small hole 11b.

[0163] Furthermore, an infrared guide section 21 can be provided from the outer edge of the infrared emitting section 23 to the entrance of the small hole 11b.

[0164] This infrared guide section 21 is conical in shape with an open bottom and top surface. The bottom opening 21b covers the recess 23c of the infrared radiating section 23, while the top opening 21c is connected to the small hole 11b of the partition wall 11, thereby creating communication between the two sections. This allows multiple far-infrared rays 29 emitted from the approximately hemispherical radiating surface 23b1 to be reflected and focused by the inner circumferential surface 21a, and guided by the heat dissipation duct 25 to the plano-concave lens 26 located at the inner end I, which is the side to be cooled.

[0165] On this inner circumferential surface 21a, as with the shade 15 mentioned above, a reflective surface is formed by attaching reflective materials such as aluminum or silver, or by applying metal plating such as chromium or nickel, or by mirror polishing or mirror finishing. This prevents the far-infrared rays 29 from the radiating surface 23b1 from being internally reflected by the inner circumferential surface 21a and emitted to the outside.

[0166] This prevents the temperature of the infrared radiation section 23 from rising due to significant distortion of the substrate 23a or uneven coating of the black film 23b, which would cause the far-infrared rays 29 emitted from the aforementioned radiating surface 23b1 to scatter to the outside instead of focusing at the focal point 20, or due to irradiation by far-infrared rays 29 from fluids other than the high-temperature air being cooled.

[0167] The radiative cooling device 1A of this embodiment is equipped with a temperature rise suppression structure 24 having an infrared radiation section 23, a small hole 11b, a heat dissipation duct 25, a plano-concave lens 26, a transparent heat insulating material 27 inside the duct, and an infrared guide section 21, as described above.

[0168] In other words, the emission section is a small hole 11b that penetrates the partition wall 11 in the thickness direction and has a smaller area than the infrared radiation section 23, the infrared radiation section 23 is positioned on the inner side I of the small hole 11b which is the cooling target side, and the temperature rise suppression structure 24 is provided on or near the focal point 20 of far-infrared rays 29 which is located at a distance from the infrared radiation section 23, and the infrared radiation section 23 has a substantially hemispherical radiation surface 23b1 with a recess 23c facing the partition wall 11 side, and the far-infrared ray section 29 is provided at a distance from the infrared radiation section 23. A small hole 11b, a cylindrical heat dissipation duct 25 inserted into the small hole 11b, a far-infrared transparent plano-concave lens 26 fitted to the inner end I of the heat dissipation duct 25 on the cooling target side, which parallelizes multiple far-infrared rays 29 from a substantially hemispherical radiating surface 23b1 and passes them through the heat dissipation duct 25, and a far-infrared transparent duct insulation material 27 fitted to the outer end O of the heat dissipation duct 25 which is on the external space side of the plano-concave lens 26, and infrared radiation In the case where the recess 23c of the radiation section 23 is covered by a bottom opening 21b, and the upper opening 21c is connected to a small hole 11b in the partition wall 11, a conical infrared guide section 21 reflects and concentrates multiple far-infrared rays 29 emitted from the radiation surface 23b1 with its inner circumferential surface 21a and guides them to the inner end I, which is the cooling target side, in the heat dissipation duct 25, an infrared radiation section 23 with a heat collection section 22 is arranged on the inner I of the small hole 11b that emits far-infrared rays 29 to the outdoors 6. However, since this small hole 11b is located on or near the focal point 20 of the far-infrared rays 29 which is spaced apart from the infrared radiation section 23, it is possible to prevent heat inflow from the outdoors 6 through the small hole 11b and sunlight irradiation through the small hole 11b to the infrared radiation section 23, thereby lowering the temperature reached by the infrared radiation section 23 during radiative cooling and ensuring high cooling efficiency.

[0169] Furthermore, since the temperature rise suppression structure 24 has an infrared radiation section 23 having a substantially hemispherical radiation surface 23b1 with a recess 23c facing the partition wall 11 side, it is possible to concentrate the far-infrared rays 29 emitted from the wide-area radiation surface 23b1 to increase the energy density, reduce radiation loss of far-infrared rays 29, and improve cooling efficiency.

[0170] Furthermore, the temperature rise suppression structure 24 includes a cylindrical heat dissipation duct 25 that is inserted into the small hole 11b, and a far-infrared transparent plano-concave lens 26 fitted to the inner end I of the heat dissipation duct 25, which parallelizes multiple far-infrared rays 29 from the substantially hemispherical radiating surface 23b1 and allows them to pass through the heat dissipation duct 25. As a result, the concentrated far-infrared rays 29 are made into parallel light, which passes through the heat dissipation duct 25 without scattering inside, and is emitted to the outside 6 by passing through the transparent heat insulating material 27 inside the duct. This reduces the scattering loss of far-infrared rays 29, further improving the cooling efficiency, and also prevents the backflow of heat to the infrared radiating part 23 due to diffuse reflection during scattering.

[0171] In addition, the temperature rise suppression structure 24 has a far-infrared transparent duct insulation material 27 fitted to the end of the heat dissipation duct 25 that is outward O from the plano-concave lens 26. As a result, the parallelized far-infrared rays 29 pass through the heat dissipation duct 25 and through the transparent duct insulation material 27 to be emitted to the outdoors 6, while heat from the outdoors 6 is blocked by the transparent duct insulation material 27. This further ensures that heat inflow from the outdoors 6 to the infrared radiation section 23 through the small holes 11b is prevented.

[0172] Furthermore, the temperature rise suppression structure 24 has a conical infrared guide portion 21 that reflects and concentrates multiple far-infrared rays 29 emitted from the approximately hemispherical radiating surface 23b1 with its inner circumferential surface 21a and guides them to the inner end I, which is the cooling target side, in the heat dissipation duct 25. This prevents multiple far-infrared rays 29 emitted from the approximately hemispherical radiating surface 23b1 from scattering far away from the concentration point 20 and outside the radiative cooling device 1A, and prevents the temperature of the infrared radiating surface 23 from rising due to far-infrared rays 29 originating from fluids other than the cooling target being irradiated from the outside, thereby ensuring even higher cooling efficiency.

[0173] Next, a different form of the radiative cooling device 1A described above, radiative cooling device 1A-a, will be explained with reference to Figure 13.

[0174] Unlike radiative cooling device 1A, the object to be cooled by this radiative cooling device 1A-a is the cooling water 45 in the water tank 81, as described above in radiative cooling devices 1-a, 1-b, and 1-c. This cooling water 45 is also poured in from the inlet pipe 46 and discharged from the outlet pipe 47. These inlet pipe 46 and outlet pipe 47 are connected to the heat exchanger 48 via piping 49. As a result, the cooling water 45 whose temperature has risen in the heat exchanger 48 is cooled by the heat collection unit 82 and then supplied to the heat exchanger 48 through piping 49, thereby forming a cooling circuit 35.

[0175] The emission section is similar to that of the radiative cooling device 1A, and is a small hole 11d with a smaller area than the infrared emission section 83, formed by penetrating the partition wall 11 in the thickness direction. Far-infrared rays 29 from the infrared emission section 83 are emitted through this small hole 11d to the outdoor space 6.

[0176] Furthermore, the shape of this infrared radiation unit 83 is the same as that of the infrared radiation unit 23 of the radiative cooling device 1A, with a recess 83c facing the partition wall 11 and being approximately hemispherical in shape. It is composed of a substrate 83a and a black coating 83b, and the far-infrared rays 29 emitted from the radiation surface 83b1 of the approximately hemispherical black coating 83b are focused at a focal point 80 located at the center of the hemisphere, spaced apart from the infrared radiation unit 83, and a small hole 11d is provided on this focal point 80.

[0177] In addition, the heat collection unit 82 attached to the infrared radiation unit 83 is similar to the heat collection unit 22 of the radiative cooling device 1A, and is configured with a plurality of vertically installed heat receiving fins 88 spaced apart at approximately equal intervals in the left-right direction, and the shape of the heat receiving fins 88 changes from a straight section to a concave section as it approaches the left and right center from the left and right ends, and a heat collection promotion structure 41d having such a heat collection unit 82 is provided.

[0178] Furthermore, the conical infrared guide section 84 is similar to the infrared guide section 21 of the radiative cooling device 1A, and is provided from the outer edge of the infrared radiating section 83 to the entrance of the small hole 11d. The recess 83c of the infrared radiating section 83 is covered by the bottom opening 84b, while the upper opening 84c is connected to the small hole 11d of the partition wall 11, thereby reflecting and concentrating multiple far-infrared rays 29 emitted from the approximately hemispherical radiating surface 83b1 with the inner circumferential surface 84a, and guiding them to the inner end I of the cylindrical heat dissipation duct 85 inserted into the aforementioned small hole 11d.

[0179] A reflective surface is also formed on this inner circumferential surface 84a, so that the far-infrared rays 29 from the radiating surface 83b1 are internally reflected by the inner circumferential surface 84a and not emitted to the outside.

[0180] However, unlike the heat dissipation duct 25 of the radiative cooling device 1A, the aforementioned heat dissipation duct 85 has a diagonally cut portion 85a at its outer end O, which faces the external space, so that the protruding side wall portion 85b has a shielding function against sunlight 7, similar to the aforementioned shades 15 and 55.

[0181] Furthermore, a reflective surface is formed on the inner circumferential surface 85c of the heat dissipation duct 85, similar to the infrared guide sections 21 and 84 described above. This allows multiple far-infrared rays emitted from the radiating surface 83b1 to be reflected by the inner circumferential surface 85c and released from the oblique cut section 85a into the outdoor space 6.

[0182] Furthermore, a transparent duct insulation material 87 that transmits far infrared rays is fitted to the outer end O of the diagonally cut portion 85a, similar to the radiative cooling device 1A. Far infrared rays 29 are released to the outdoor space 6 by passing through the transparent duct insulation material 87 through the heat dissipation duct 85, while heat from the outdoor space 6 is blocked by this transparent duct insulation material 87.

[0183] The radiative cooling device 1A-a of this embodiment is provided with a temperature rise suppression structure 89 having an infrared radiation section 83, a small hole 11b, a heat dissipation duct 85, a transparent heat insulating material 87 inside the duct, and an infrared guide section 84, as described above.

[0184] In other words, the emission part is a small hole 11d that penetrates the partition wall 11 in the thickness direction and has a smaller area than the infrared emission part 83, and the infrared emission part 83 is positioned on the inner side I of the small hole 11d which is the cooling target side, and the temperature rise suppression structure 89 is an infrared emission part 83 having a substantially hemispherical radiating surface 83b1 with a recess 83c facing the partition wall 11 side, a small hole 11d provided on or near the focal point 80 of far-infrared rays 29 which is spaced apart from the infrared emission part 83, a cylindrical heat dissipation duct 85 which is inserted into the small hole 11d and has an oblique cut portion 85a at the tip of the outer side O which is the external space side, and reflects a plurality of far-infrared rays 29 emitted from the radiating surface 83b1 with its inner circumferential surface 85c and emits them from the oblique cut portion 85a to the outdoor space 6, which is the external space, and a far-infrared transparent duct insulation material 87 which is fitted into the oblique cut portion 85a of the heat dissipation duct 85, and infrared emission part In the case where the recess 83c of 83 is covered by the bottom opening 84b, and the upper opening 84c is connected to the small hole 11d of the partition wall 11, a conical infrared guide portion 84 is provided that reflects and concentrates multiple far-infrared rays 29 emitted from the radiating surface 83b1 with the inner circumferential surface 84a and guides them to the inner end I, which is the cooling target side, in the heat dissipation duct 85, an infrared radiating portion 83 with a heat collecting portion 82 is arranged on the inner I of the small hole 11d that emits the far-infrared rays 29 to the outdoors 6. However, since this small hole 11d is provided on or near the focal point 80 of the far-infrared rays 29 which is spaced apart from the infrared radiating portion 83, it is possible to prevent heat inflow from the outdoors 6 through the small hole 11d and to prevent sunlight irradiation through the small hole 11d to the infrared radiating portion 83, thereby lowering the temperature reached by the infrared radiating portion 83 during radiative cooling and ensuring high cooling efficiency.

[0185] Furthermore, since the temperature rise suppression structure has an infrared radiation section 83 having a substantially hemispherical radiation surface 83b1 with a recess 83c facing the partition wall 11 side, it is possible to concentrate the far-infrared rays 29 emitted from the wide-area radiation surface 83b1 to increase the energy density, reduce radiation loss of far-infrared rays 29, and improve cooling efficiency.

[0186] Furthermore, the temperature rise suppression structure 89 is inserted into the small hole 11d and has an oblique cut portion 85a at its outer tip O. It also has a cylindrical heat dissipation duct 85 that reflects multiple far-infrared rays 29 emitted from the radiating surface 83b1 with its inner circumferential surface 85c and releases them to the outdoors 6 through the oblique cut portion 85a. As a result, sunlight 7 is reliably blocked by the side wall portion 85b protruding from the oblique cut portion 85a of the heat dissipation duct 85, and the far-infrared rays 29 are released to the outdoors 6 through the heat dissipation duct 85 by internal reflection even without parallelization. Therefore, large parts such as shades 15 and 55 for blocking sunlight and special parts and structures such as the plano-concave lens 26 for parallelizing infrared rays are not required, which reduces the cost of the device and improves maintainability.

[0187] In addition, the temperature rise suppression structure 89 has a far-infrared transparent duct insulation material 87 fitted into the diagonally cut portion 85a of the heat dissipation duct 85. As a result, far-infrared rays 29 passing through the heat dissipation duct 85 are transmitted through the duct insulation material 87 and released to the outdoors 6, while heat from the outdoors 6 is blocked by the duct insulation material 87. This further reliably prevents heat from flowing from the outdoors 6 to the infrared radiation section 83 through the small holes 11d.

[0188] Furthermore, the temperature rise suppression structure 89 has a conical infrared guide section 84 that reflects and concentrates multiple far-infrared rays 29 emitted from the radiating surface 83b1 with its inner circumferential surface 84a and guides them to the inner end I in the heat dissipation duct 85. This prevents multiple far-infrared rays 29 emitted from the approximately hemispherical radiating surface 83b1 from scattering far away from the focal point 80 and outside the radiative cooling device 1A-a, and prevents the temperature of the infrared radiating surface 83 from rising due to far-infrared rays 29 originating from fluids other than the object being cooled being irradiated from the outside, thereby ensuring even higher cooling efficiency.

[0189] Next, a different form of the radiative cooling device 1A described above, radiative cooling device 1A-b, will be explained with reference to Figure 14.

[0190] Unlike radiative cooling device 1A, the object to be cooled in this radiative cooling device 1A-b is the cooling water 45 in the water tank 91, just like in radiative cooling device 1A-a. This cooling water 45 is also poured in from the inlet pipe 46 and discharged from the outlet pipe 47, forming a cooling circuit 35.

[0191] Furthermore, the emission section is similar to that of the radiative cooling device 1A, and is a small hole 11d with a smaller area than the infrared emission section 83, and is formed to penetrate the partition wall 11 in the thickness direction, so that the far-infrared rays 29 from the infrared emission section 93 are emitted to the outdoor space 6 through this small hole 11d.

[0192] Unlike the radiative cooling device 1A, the heat dissipation duct 85 of the radiative cooling device 1A-a is inserted into this small hole 11d, and a diagonally cut portion 85a is provided at the outer tip O of the heat dissipation duct 85, into which a far-infrared transparent duct insulation material 87 is fitted.

[0193] However, the infrared radiation unit 93 and the heat collection unit 82 attached to the infrared radiation unit 93 are different from those of both the radiative cooling device 1A and 1A-a.

[0194] The infrared radiation section 93 is similar to the infrared radiation sections 3.53 of the radiative cooling devices 1, 1-a, 1-b, and 1-c, and is not hemispherical but a flat plate shape, and is composed of a substrate 93a having a heat receiving surface 93a1 on its inner side I to which the outer ends of the heat receiving fins 8 are implanted, and a black coating 93b formed on this substrate 93a, the surface of which the black coating 93b becomes a radiation surface 93b1 that emits far-infrared rays 29.

[0195] Therefore, the heat collection section 82 is the same as the heat collection sections 2.52 of the radiative cooling devices 1, 1-a, 1-b, and 1-c, and is composed of multiple vertically installed heat receiving fins 8 of the same shape, spaced apart at approximately equal intervals in the left-right direction, and a heat collection promotion structure 41e having such a heat collection section 82 is provided.

[0196] Furthermore, unlike the radiative cooling devices 1A and 1A-a, the infrared guide section 94 is not conical but has a composite parabolic surface with high light-gathering performance on its inner circumferential surface 94a. By covering the flat portion 93c of the infrared radiation section 93 of the flat radiation surface 93b1 with the bottom opening 94b, while connecting the upper opening 94c to the small hole 11d of the partition wall 11, even far-infrared rays 29 that do not have the aforementioned focal points 20 and 80 because they are emitted from the flat radiation surface 93b1 can be reflected by the inner circumferential surface 94a of the composite parabolic surface, efficiently focusing them into the focal portion 90 spaced away from the infrared radiation section 93. This ensures that the far-infrared rays 29 are reliably guided to the inner end I of the heat dissipation duct 85, which is inserted into the small hole 11d in this focal portion 90.

[0197] The radiative cooling device 1A-b of this embodiment is provided with a temperature rise suppression structure 99 having an infrared radiation section 93, a small hole 11d, a heat dissipation duct 85, a transparent heat insulating material 87 inside the duct, and an infrared guide section 94, as described above.

[0198] In other words, the emission part is a small hole 11d that penetrates the partition wall 11 in the thickness direction and has a smaller area than the infrared radiation part 93, the infrared radiation part 93 is positioned on the cooling target side of the small hole 11d, and the temperature rise suppression structure 99 is an infrared radiation part 93 having a flat radiation surface 93b1 facing the partition wall 11 side, a small hole 11d provided in the far-infrared 29 concentrating part 90 located spaced apart from the infrared radiation part 93, a cylindrical heat dissipation duct 85 that is inserted into the small hole 11d and has an oblique cut portion 85a at the outer end O which is on the external space side, and reflects a plurality of far-infrared rays 29 emitted from the radiation surface 93b1 with its inner circumferential surface 94a and emits them from the oblique cut portion 85a to the outdoor space 6, which is the external space, and a far-infrared transparent duct insulation material 87 fitted into the oblique cut portion 85a of the heat dissipation duct 85, and the flat portion 93c of the infrared radiation part 93 In the case where the bottom opening 94b covers the bottom opening 94b, and the upper opening 94c is connected to the small hole 11d of the partition wall 11, and there is a composite parabolic infrared guide section 94 that reflects and concentrates multiple far-infrared rays 29 emitted from the radiating surface 93b1 with the inner circumferential surface 94a and guides them to the inner end I, which is the cooling target side, in the heat dissipation duct 85, an infrared radiating section 93 with a heat collecting section 92 is arranged on the inner I of the small hole 11d that emits the far-infrared rays 29 to the outdoors 6, but since this small hole 11d is provided in the far-infrared radiating section 90 which is spaced apart from the infrared radiating section 93, it is possible to prevent heat inflow from the outdoors 6 through the small hole 11d and to prevent sunlight irradiation through the small hole 11d to the infrared radiating section 93, thereby lowering the temperature reached by the infrared radiating section 93 during radiative cooling and ensuring high cooling efficiency.

[0199] Furthermore, the temperature rise suppression structure 99 is inserted into the small hole 11d and has an oblique cut portion 85a at the outer tip O, and has a cylindrical heat dissipation duct 85 that reflects multiple far-infrared rays 29 emitted from the radiating surface 93b1 with its inner circumferential surface 94a and releases them to the outdoors 6 from the oblique cut portion 85a. As a result, sunlight 7 is reliably blocked by the side wall portion 85b protruding from the oblique cut portion 85a of the heat dissipation duct 85, and the far-infrared rays 29 are released to the outdoors 6 through the heat dissipation duct 85 by internal reflection even without parallelization. Therefore, large parts such as shades 15 and 55 for shielding sunlight and special parts and structures such as the plano-concave lens 26 for parallelizing infrared rays are not required, which can reduce equipment costs and improve maintainability.

[0200] Furthermore, since the temperature rise suppression structure 99 has a far-infrared transparent duct insulation material 87 fitted into the diagonally cut portion 85a of the heat dissipation duct 85, far-infrared rays 29 passing through the heat dissipation duct 85 are transmitted through the duct insulation material 87 and released to the outdoors 6, while heat from the outdoors 6 is blocked by the duct insulation material 87, thereby more reliably preventing heat from flowing from the outdoors 6 to the infrared radiation section 93 through the small holes 11d.

[0201] In addition, the temperature rise suppression structure 99 has a composite parabolic infrared guide section 94 that covers the flat section 93c of the infrared radiation section 93 with a bottom opening 94b, while connecting the upper opening 94c to a small hole 11d in the partition wall 11. This section reflects and concentrates multiple far-infrared rays 29 emitted from the radiation surface 93b1 with its inner circumferential surface 94a and guides them to the inner end I in the heat dissipation duct 85. As a result, many of the multiple far-infrared rays emitted from the flat radiation surface 93b1 can be reliably guided to the inner end I by the inner circumferential surface 94a of the composite parabolic surface with high light-gathering performance. Furthermore, it prevents the far-infrared rays 29 from scattering outside the radiative cooling device 1A-b, and prevents the temperature of the infrared radiation section 93 from rising due to far-infrared rays 29 originating from fluids other than the object being cooled being irradiated from the outside, thereby ensuring even higher cooling efficiency. Furthermore, it becomes unnecessary to configure the infrared radiation unit 93 in a roughly hemispherical shape to improve the light-gathering performance. This allows for a simpler structure not only for the infrared radiation unit 93 but also for the heat-receiving fins 8 of the heat-collecting unit 92 that are installed on its heat-receiving surface 93a1, thereby reducing equipment costs and further improving maintainability.

[0202] Next, a different form of radiative cooling device 1B, described above, will be explained with reference to Figures 15 to 17.

[0203] The discharge section of this radiative cooling device 1B, like the aforementioned radiative cooling devices 1A, 1A-a, and 1A-b, is a small hole 11c with a smaller area than the infrared radiation section 33, unlike the aforementioned opening window 12 in the radiative cooling device 1 which has substantially the same shape and area as the infrared radiation section 3. It is formed by penetrating the partition wall 11 in the thickness direction.

[0204] Then, the far-infrared rays 29 from the infrared radiation unit 33, which is located on the inner side I of the small hole 11c that is to be cooled, are emitted through the small hole 11c to the outdoor space 6.

[0205] Furthermore, the infrared radiation section 33 is the same as the infrared radiation section 3 of the radiative cooling device 1 in both shape and structure. It has a flat plate shape, and its structure consists of a substrate 33a having a flat heat-receiving surface 33a1 on its inner side I, and a black coating 33b formed on the coated surface 33a2 on the substrate 33a opposite to the heat-receiving surface 33a1. The surface of this black coating 33b is the radiation surface 33b1 that emits far-infrared rays 29.

[0206] The structure of the heat collection unit 32 attached to the infrared radiation unit 33 is the same as that of the heat collection unit 2 of the radiative cooling device 1, and consists of a plurality of vertically installed heat receiving fins 38 spaced approximately equally apart in the left-right direction. The inner part I of the heat collection unit 32 is exposed to the inside of the building 5, while the outer part O of the heat collection unit 32 has the outer ends of all of its heat receiving fins 38 embedded in the heat receiving surface 33a1 of the infrared radiation unit 33, and a heat collection promotion structure 41f having such a heat collection unit 32 is provided.

[0207] In this heat collection section 32, similar to the heat collection section 2 of the radiative cooling device 1, the use of multiple heat receiving fins 38 greatly expands the heat collection area, allowing a large amount of heat to flow in. Heat also flows in through thermal convection in the gaps between the heat receiving fins 38, and the heat from the high-temperature air, which is the fluid to be cooled, can be efficiently collected in the infrared radiation section 33 by thermal conduction and thermal convection.

[0208] Furthermore, multiple concentrators 30 are arranged on the radiating surface 33b1 that emits far-infrared rays 29.

[0209] The light concentrator 30 is conical in shape with an open bottom, and the bottom opening 30a of the bottom is fitted over the radiating surface 33b1. The inner circumferential surface 30b of the light concentrator 30 is formed by attaching a reflective material such as aluminum or silver, or by applying metal plating such as chromium or nickel, or by mirror polishing or mirror finishing, similar to the infrared guide section 21 described above.

[0210] Therefore, the heat collected by the heat collecting unit 32 in the infrared radiation unit 33 is radiated as far-infrared rays 29 from the radiation surface 33b1, and then enters each concentrator 30 from the bottom opening 30a. These far-infrared rays 29 are internally reflected by the inner circumferential surface 30b and concentrated near the apex 30c.

[0211] However, of the far-infrared rays 29 that enter the light concentrator 30, most of those that are not focused near the vertex 30c but undergo repeated internal reflection can ultimately be focused near the vertex 30c of the light concentrator 30 by optimizing the incident conditions and the inner surface 30b, for example, by reducing the incident angle or making the inner surface 30b a composite parabolic surface.

[0212] As a result, by using the concentrator 30, the far-infrared rays 29 from the radiating surface 33b1 can be concentrated to increase the energy density, reduce radiation loss of the far-infrared rays 29, and improve cooling efficiency.

[0213] Furthermore, an optical fiber section 31 is arranged from the light concentrator 30 to the small hole 11c.

[0214] This optical fiber section 31 consists of an optical fiber 31a, one end of which is optically connected to the vertex 30c of each of the aforementioned light concentrators 30, and an insulating optical fiber bundle 31b formed by the aggregation of the other ends of each optical fiber 31a, and this optical fiber bundle 31b is inserted into the aforementioned small hole 11c.

[0215] As a result, the far-infrared rays 29, which are focused by multiple concentrators 30 covering the radiating surface 33b1, are collected through numerous optical fibers 31a and can be emitted together from a single optical fiber bundle 31b into the outdoor space 6.

[0216] By providing the light concentrators 30 and optical fiber section 31 as described above, even if the radiating surface 33b1 has a shape that prevents the far-infrared rays 29 from being focused in one place, such as a flat surface like the radiative cooling devices 1 and 1B, or a wavy curved surface, simply covering the radiating surface 33b1 with the bottom openings 30a of the multiple light concentrators 30 allows the far-infrared rays 29 emitted from the radiating surface 33b1 within the bottom openings 30a to be focused near the vertices 30c of each light concentrator 30, then sent through each optical fiber 31a to the optical fiber bundle 31b, and finally emitted into the outdoor space 6 through the small hole 11c into which the optical fiber bundle 31b is inserted.

[0217] Furthermore, by simply adjusting the length of the optical fiber 31a and optical fiber bundle 31b of the optical fiber section 31, the position of the small hole 11c into which the optical fiber bundle 31b is inserted can also be freely changed.

[0218] Furthermore, since the light concentrator 30 and the optical fiber section 31 are interposed between the aforementioned infrared radiation section 33 and the small hole 11c, the small hole 11c is located at a distance from the infrared radiation section 33.

[0219] As a result, even if a gap is created between the small hole 11c and the optical fiber bundle 31b, and heat from the hot air outdoors 6 tries to flow into the infrared radiating section 33 through this gap, or sunlight 7 tries to irradiate the infrared radiating section 33, the small hole 11c is located at a distance from the infrared radiating section 33, so the heat and sunlight 7 that reach the infrared radiating section 33 are attenuated or blocked by the concentrator 30 and the optical fiber section 31.

[0220] The radiative cooling device 1B of this embodiment is equipped with a light collector 30, an optical fiber section 31, and a temperature rise suppression structure 34 having the small holes 11c, all configured as described above.

[0221] In other words, the emission part is a small hole 11c that penetrates the partition wall 11 in the thickness direction and has a smaller area than the infrared emission part 33, the infrared emission part 33 is positioned on the inner side I of the small hole 11c which is the cooling target side, and the temperature rise suppression structure 34 has a bottom opening 30a covering the radiating surface 33b1 of the infrared emission part 33, a conical light concentrator 30 that focuses the far infrared rays 29 emitted from the radiating surface 33b1 directly or by internal reflection to the vicinity of the apex 30c, one end of an optical fiber 31a is connected to the apex 30c of the light concentrator 30, and the other end of the optical fiber 31a is gathered to form an insulating optical fiber bundle 31b, and the focused far infrared rays 29 are emitted via the inserted optical fiber bundle 31b In the case where the infrared radiation unit 33 emits far-infrared rays 29 into the outdoor space 6 and has a small hole 11c located spaced apart from the infrared radiation unit 33 by a concentrator 30 and an optical fiber unit 31, the infrared radiation unit 33 with a heat collection promotion structure 41f is positioned on the inner side I of the cooling target side of the small hole 11c that emits far-infrared rays 29 into the outdoor space 6. However, since this small hole 11c is located spaced apart from the infrared radiation unit 33 by a concentrator 30 and an optical fiber unit 31, it is possible to prevent heat inflow from the outdoor space 6 to the infrared radiation unit 33 through the small hole 11c and to prevent sunlight irradiation through the small hole 11c, thereby lowering the temperature reached by the infrared radiation unit 33 during radiative cooling and ensuring high cooling efficiency.

[0222] Furthermore, the temperature rise suppression structure 34 has a bottom opening 30a covering the radiating surface 33b1 of the infrared radiation section 33, and includes a conical light concentrator 30 that focuses the far-infrared rays 29 emitted from the radiating surface 33b1 directly or by internal reflection to the vicinity of the apex 30c, and an optical fiber section 31 in which one end of an optical fiber 31a is connected to the tip of the light concentrator 30, and the other end of the optical fiber 31a is gathered to form an insulating optical fiber bundle 31b. By adjusting the length of the optical fiber 31a and the optical fiber bundle 31b of the optical fiber section 31, the position of the small hole 11c into which the optical fiber bundle 31b is inserted can be freely changed, and heat inflow from the outdoors 6 through the small hole 11c and sunlight irradiation through the small hole 11c can be prevented even more reliably from reaching the infrared radiation section 33.

[0223] Furthermore, even if some of the far-infrared rays 29 from the radiating surface 33b1 are repeatedly reflected internally without being focused near the apex 30c of the light concentrator 30, by optimizing the angle of incidence from the bottom opening 30a and the shape of the inner surface 30b, for example by reducing the angle of incidence or making the inner surface 30b a composite parabolic surface, most of these rays can ultimately be focused near the apex 30c of the light concentrator 30, thereby preventing a decrease in focusing performance.

[0224] Furthermore, even if the radiating surface 33b1 has a shape that prevents the far-infrared rays 29 from being focused in one place, such as a flat surface or a wavy curved surface, simply covering the radiating surface 33b1 with the bottom openings 30a of multiple concentrators 30 allows the far-infrared rays 29 emitted from the radiating surface 33b1 within the bottom openings 30a to be focused near the vertices 30c of each concentrator 30, then sent through each optical fiber 31a to the optical fiber bundle 31b, and finally emitted into the outdoor space 6 through the small holes 11c into which the optical fiber bundle 31b is inserted. As a result, regardless of the shape of the radiating surface 33b1 of the infrared radiating unit 33, the far-infrared rays 29 emitted from a large-area radiating surface 33b1 can be focused to increase the energy density, and even with a compact device, radiation loss of far-infrared rays 29 can be reduced and cooling efficiency can be improved.

[0225] Next, a different form of the radiative cooling device 1B described above, radiative cooling device 1B-a, will be explained with reference to Figures 18 and 19.

[0226] This radiative cooling device 1B-a is an improved version of the radiative cooling device 1B described above, with an improved focusing configuration using a light concentrator 30, thereby enhancing the focusing ability of far-infrared rays 29 to the apex of the light concentrator 30.

[0227] Since its configuration is the same as that of radiative cooling device 1B, except for the light-concentrating configuration, in Figures 18 and 19, the same reference numerals are used for components that are the same as those in radiative cooling device 1B, and their explanations are omitted.

[0228] The focusing configuration of the radiative cooling device 1B-a consists of a light concentrator 40 having substantially the same structure as the light concentrator 30 of the radiative cooling device 1B, and a convex lens 41 covering the bottom opening 40a of the light concentrator 40. This convex lens 41 is positioned on the radiating surface 33b1 of the infrared radiating section 33 of the radiative cooling device 1B, and is interposed between this radiating surface 33b1 and the bottom opening 40a of the light concentrator 40.

[0229] Furthermore, the bottom opening 40a has an end cut at an angle, and the convex lens 41 is positioned so that its surface abuts against this end.

[0230] The focal position of the convex lens 41 is set to the apex 40c of the conical light condenser 40, and the far-infrared rays 29 emitted from the radiating surface 33b1 parallel to the optical central axis 40d of the light condenser 40 are focused near the apex 40c after passing through the convex lens 41.

[0231] This reduces the proportion of far-infrared rays 29 emitted from the radiating surface 33b1 that are focused near the vertex 40c after undergoing internal reflection multiple times q on the inner surface 40b of the light concentrator 40. As a result, most of the far-infrared rays 29 can be directly focused near the vertex 40c by the convex lens 41, thereby suppressing scattering caused by internal reflection and reducing the scattering loss of far-infrared rays 29. In addition, similar to the light concentrator 30 described above, the inner surface 40b of the light concentrator 40 is also formed by attaching reflective materials such as aluminum or silver, or by applying metal plating such as chromium or nickel, or by mirror polishing or mirror finishing.

[0232] The radiative cooling device 1B-a of this embodiment is equipped with a light collector 40, a convex lens 41, an optical fiber section 31, and a temperature rise suppression structure 44 having a small hole 11c, all configured as described above.

[0233] In other words, if the temperature rise suppression structure 44 has a far-infrared transparent convex lens 41 between the radiating surface 33b1 of the infrared radiating section 33 and the bottom opening 40a of the concentrator 40, which focuses the far-infrared rays 29 from the radiating surface 33b1 onto the apex 40c of the concentrator 40, then by directly focusing most of the far-infrared rays 29 emitted from the radiating surface 33b1 onto the vicinity of the apex 40c with the convex lens 41, scattering caused by internal reflection can be suppressed, reducing the scattering loss of far-infrared rays 29 and further improving the cooling efficiency.

[0234] Next, a different form of the radiative cooling device 1B described above, radiative cooling device 1B-b, will be explained with reference to Figure 20.

[0235] This radiative cooling device 1B-b is an improved version of the heat collection enhancement structure 41f of the aforementioned radiative cooling device 1B, with the aim of simplifying the parts and structure and improving versatility.

[0236] In the heat collection promotion structure 41g of the radiative cooling device 1B-b, the housing 102 surrounding the heat-generating elements 101 such as the CPU, power semiconductors, generator, and transformer of the data server functions as the substrate for the infrared radiation unit 113.

[0237] In other words, a heat receiving surface 102a is formed on the inside of the housing 102, and heat from the heating element 101 can efficiently flow into this heat receiving surface 102a through heat transfer via the support frame between the heating element 101 and the housing 102, thermal convection by the high-temperature air heated by the heating element 101 in the sealed space inside the housing 102, and thermal radiation from far-infrared rays emitted from the surface of the heating element 101.

[0238] On the other hand, on the outside of the housing 102, a black coating 106 is applied to the coated surface 102b opposite to the heat-receiving surface 102a as described above, and the surface of this black coating 106 becomes a radiating surface 106a that emits far-infrared rays 29.

[0239] Therefore, by simply applying a black coating 106 to the surface of the existing housing 102, the heat collection promotion structure 41g of this radiant cooling device 1B-b, which efficiently collects heat from the heating element 101 and emits it as far-infrared radiation, can be easily constructed.

[0240] In other words, if the heat collection promotion structure 41g has an infrared radiation section 113 which is configured by forming a heat receiving surface 102a on the inside of a housing 102 surrounding the heat-generating element 101 to be cooled, into which heat from the heat-generating element 101 flows, and forming a radiation surface 106a on the outside of the housing 102, then because the heat-generating element 101 is surrounded by the housing 102, by forming the radiation surface 106a on the existing housing 102 by applying a black coating 106 or the like, and then retrofitting the radiative cooling device 1B-b of the present invention, most of the heat from the heat-generating element 101 can flow into the heat receiving surface 102a without escaping and be radiated from the radiation surface 106a. As a result, many parts and complex structures such as heat receiving fins are unnecessary, which can reduce the cost of the device and improve maintainability, and it can also be introduced to improve cooling capacity when the existing cooling system alone is not sufficient.

[0241] Furthermore, regarding the thermal radiation from the aforementioned heating element 101, applying the black coating 107 to the heat receiving surface 102a promotes the inflow of radiant heat to the infrared radiation section 113. Therefore, when newly installing the housing 102 on the heating element 101, it is preferable to apply the black coatings 106 and 107 to both the inner and outer surfaces of the housing 102.

[0242] Furthermore, the emission section of the radiative cooling device 1B-b is the same as that of the radiative cooling device 1B, and is a small hole 11c with a smaller area than the infrared emission section 113, and is formed to penetrate the partition wall 11 in the thickness direction.

[0243] Furthermore, multiple concentrators 100 are arranged on the aforementioned radiating surface 106a that emits far-infrared rays 29, similar to the radiative cooling device 1B.

[0244] The light concentrator 100 has a bottom opening 100a that covers the radiating surface 106a, and a reflective surface is formed on the inner circumferential surface 100b of the light concentrator 100. The heat collected by the aforementioned heat collection promotion structure 41g to the infrared radiation section 113 is radiated from the radiating surface 106a as far-infrared rays 29, and then enters each light concentrator 100 from the bottom opening 100a. These far-infrared rays 29 are internally reflected by the inner circumferential surface 100b and focused near the apex 100c.

[0245] However, unlike the concentrator 30 of the radiative cooling device 1B, the concentrator 100 is not conical but a composite parabolic surface. Therefore, it can concentrate multiple far-infrared rays 29 emitted from the radiating surface 106a to the vicinity of the vertex 100c more efficiently than in the case of a conical shape.

[0246] In other words, if the bottom opening 100a of the light concentrator 100 is covered on the radiating surface 106a of the infrared radiating section 113, and the light concentrator 100 is a composite parabolic shape that concentrates the far infrared rays 29 radiated from the radiating surface 106a to the vicinity of its apex 100c, then even if some of the far infrared rays 29 from the radiating surface 106a undergo repeated internal reflection without being concentrated to the vicinity of the apex 100c of the light concentrator 100, by making the light concentrator a composite parabolic shape and optimizing the shape of the inner surface 100b by making the inner surface a composite parabolic shape, then the majority of these rays can ultimately be concentrated to the vicinity of the apex 100c of the light concentrator 100, thereby preventing a decrease in light concentrating performance.

[0247] Furthermore, in the same manner as the radiative cooling device 1B, an optical fiber section 103 is arranged from the light concentrator 100 to the small hole 11c.

[0248] This optical fiber section 103 consists of an optical fiber 103a, one end of which is optically connected to the vertex 100c of each light concentrator 100, and an insulating optical fiber bundle 103b formed by the other ends of each optical fiber 103a. This optical fiber bundle 31b is inserted into the aforementioned small hole 11c, and the far-infrared rays 29 focused by the multiple light concentrators 100 covering the radiating surface 106a can be collected through a large number of optical fibers 103a and emitted together from a single optical fiber bundle 103b into the outdoor space 6.

[0249] Furthermore, a radiator 105 capable of emitting far-infrared rays 29 that have passed through the optical fiber 103a with high emissivity is provided at the end of the optical fiber bundle 103b.

[0250] This radiator 105 can be a ceramic, far-infrared radiating paint, or photoelectronic fiber, and absorbs the far-infrared rays 29 emitted from the tip of the optical fiber bundle 103b on its back surface 105a, and then emits them to the outdoors 6 from its front surface 105b.

[0251] In this case, by reducing the cross-sectional area of ​​the radiator 105, and then reducing the gaps between the optical fibers 103a within the optical fiber bundle 103b to match that cross-sectional area, and also reducing the cross-sectional area of ​​the tip of the optical fiber bundle 103b, the amount of far-infrared rays 29 emitted from the surface 105b of the radiator 105 to the outdoors 6 can be reduced, thereby also reducing the size of the holes 11c through which the optical fiber bundle 103b passes.

[0252] In other words, when a radiator 105 capable of emitting far-infrared rays 29 with high emissivity is provided at the end of the optical fiber section 103, the cross-sectional area of ​​the radiator 105 can be reduced, thereby reducing the size of the small holes 11c, and further reliably preventing heat inflow from the outdoor space 6 through the small holes 11c and sunlight irradiation.

[0253] The radiative cooling device 1B-b of this embodiment is equipped with a light collector 100, an optical fiber section 103, and a temperature rise suppression structure 104 having the small holes 11c, as described above.

[0254] In other words, the emission part is a small hole 11c that penetrates the partition wall 11 in the thickness direction and has a smaller area than the infrared emission part 113, the infrared emission part 113 is positioned on the inner side I of the small hole 11c which is the cooling target side, and the temperature rise suppression structure 104 has a bottom opening 100a covering the radiating surface 106a of the infrared emission part 113, and a composite parabolic concentrator 100 that focuses the far infrared rays 29 emitted from the radiating surface 106a directly or by internal reflection to the vicinity of the apex 100c, and one end of an optical fiber 103a is connected to the apex 100c of the concentrator 100, and the other end of the optical fiber 103a is gathered to form an insulating optical fiber bundle 103b, and the focused far infrared rays When the infrared radiation 29 is emitted into the outdoor space 6, and the infrared radiation unit 113 has a small hole 11c located spaced apart from it by a concentrator 100 and an optical fiber unit 103, the infrared radiation unit 113 with a heat collection promotion structure 41g is positioned on the inner side I of the small hole 11c that emits far-infrared rays 29 into the outdoor space 6. However, since the small hole 11c is located spaced apart from the infrared radiation unit 113 by a concentrator 100 and an optical fiber unit 103, it is possible to prevent heat inflow from the outdoor space 6 to the infrared radiation unit 113 through the small hole 11c and to prevent sunlight irradiation through the small hole 11c, thereby lowering the temperature reached by the infrared radiation unit 113 during radiative cooling and ensuring high cooling efficiency.

[0255] Furthermore, the temperature rise suppression structure 104 has a bottom opening 100a covering the radiating surface 106a of the infrared radiation section 113, and a composite parabolic concentrator 100 that focuses the far-infrared rays 29 radiated from the radiating surface 106a directly or by internal reflection near the apex 100c, and an optical fiber section 103 in which one end of an optical fiber 103a is connected to the apex 100c of the concentrator 100, and the other end of the optical fiber 103a is gathered to form an insulating optical fiber bundle 103b. Therefore, by simply adjusting the length of the optical fiber 103a and the optical fiber bundle 103b of the optical fiber section 103, the position of the small hole 11c into which the optical fiber bundle 103b is inserted can be freely changed, and heat inflow from the outdoors 6 through the small hole 11c and sunlight irradiation through the small hole 11c can be prevented even more reliably from reaching the infrared radiation section 113.

[0256] Furthermore, even if the radiating surface 106a has a shape that prevents the far-infrared rays 29 from being focused in one place, such as a flat surface or a wavy curved surface, simply covering the radiating surface 106a with the bottom openings 100a of multiple concentrators 100 allows the far-infrared rays 29 emitted from the radiating surface 106a within the bottom openings 100a to be focused near the vertices 100c of each concentrator 100, then sent through each optical fiber 103a to the optical fiber bundle 103b, and finally emitted into the outdoor space 6 through the small holes 11c into which the optical fiber bundle 103b is inserted. As a result, regardless of the shape of the radiating surface 106a of the infrared radiation unit 113, the far-infrared rays 29 emitted from a large-area radiating surface 106a can be focused to increase the energy density, reducing radiation loss of far-infrared rays 29 and improving cooling efficiency, even with a compact device.

[0257] Furthermore, if a radiator 105 capable of emitting far-infrared rays with high emissivity is provided at the end of the optical fiber section 103, the cross-sectional area of ​​the radiator 105 can be reduced to more reliably prevent sunlight from irradiating the infrared radiation section 113 through the small holes 11c, or conversely, the cross-sectional area of ​​the radiator 105 can be increased to make the optical fiber 103a thicker and increase the amount of far-infrared rays 29 emitted, making it easier to adapt to various device environments.

[0258] As described above, the radiative cooling device according to the present invention, by having an infrared radiation section with a heat collection promotion structure, can efficiently collect heat from the object to be cooled into the infrared radiation section without the need for a special structure. Furthermore, by having a temperature rise suppression structure that reliably prevents heat inflow from the external space and irradiation by sunlight into the infrared radiation section, the temperature reached by the infrared radiation section during radiative cooling is lowered, ensuring high cooling efficiency even in various environments.

[0259] Although the present invention has been described through the above embodiments, the present invention is not limited to these embodiments. Furthermore, the effects described above are merely a list of the most preferred effects arising from the present invention, and the effects of the present invention are not limited to those described in these embodiments.

[0260] 2.22.32 Heat collecting section 3.23.33.53.83.93.113 Infrared radiating section 3a1.23a1.33a1.102a Heat receiving surface 3b1.23b1.33b1.83b1.93b1.106a Radiating surface 4.24.34.44.51a.51b.51c.89.99.104 Temperature rise suppression structure 6 Outdoor (external space) 7 Sunlight 8.28.38 Heat receiving fins 11 Partition wall 11b.11c.11d Small holes 12.59 Opening window (emission section) 14.54 Transparent insulation material inside the window 15.55 Shade 16 Detachable structure 20.80 Focusing point 21.84.94 Infrared guide section 21a, 84a, 94a Inner surface (of infrared guide section) 21b, 84b, 94b Bottom opening (of infrared guide section) 21c, 84c, 94c Top opening 23c, 83c Recess 25, 85 Heat dissipation duct 26 Plano-concave lens 26 27, 87 Transparent insulation material inside the duct 29 Far infrared rays 30, 40, 100 Concentrator 30a, 40a, 100a Bottom opening (of concentrator) 30c, 40c, 100c Apex 31, 103 Optical fiber section 31a, 103a Optical fiber 31b, 103b Optical fiber bundle 41 Convex lens 41a, 41g Heat collection promotion structure 56a Control unit 56b Battery 57 Solar panel 60a, 60b, 60c Switching mechanism 61 Dimming panel 62 Power supply device 64 Shutter body 74 Light-shielding curtain 85a Diagonal cut section 85c・94a Inner surface (of heat dissipation duct) 90 Light-collecting section 93c Flat section 102 Housing 105 Radiator I Inner side (cooling target side) O Outer side (external space side)

Claims

1. A radiative cooling device comprising: a heat collection promotion structure that promotes heat collection from a cooling target; an infrared radiation section in which heat flows into a heat receiving surface by the heat collection promotion structure, while the incoming heat is radiated as far-infrared radiation from a radiating surface opposite to the heat receiving surface; a discharge section provided in a partition wall separating the infrared radiation section from the external space, which discharges far-infrared radiation from the radiating surface into the external space; and a temperature rise suppression structure between the radiating surface and the external space that prevents heat inflow from the external space to the infrared radiation section via the discharge section and irradiation by sunlight, thereby suppressing the temperature rise of the infrared radiation section.

2. The radiative cooling device according to claim 1, characterized in that the heat collection promotion structure has a heat collection section comprising plate-shaped heat receiving fins, which are embedded in the heat receiving surface and into which heat flows, arranged within the fluid to be cooled.

3. The radiant cooling device according to claim 2, characterized in that the emission section is an opening window opened in a partition wall having substantially the same shape and area as the infrared radiation section, the infrared radiation section covering the side of the opening window that is to be cooled, and the temperature rise suppression structure comprises a far-infrared transparent window insulation material fitted in the opening window on the side of the opening window that is closer to the external space than the infrared radiation section, a shade erected on the side of the opening window that blocks sunlight, and a removable structure that allows the shade, which is optimized according to the installation conditions of the opening window, to be replaced.

4. The radiative cooling device according to claim 2, characterized in that the emission section is an opening window opened in a partition wall having substantially the same shape and area as the infrared radiation section, the infrared radiation section covering the side of the opening window that is to be cooled, and the temperature rise suppression structure comprises a far-infrared transparent window insulation material fitted in the opening window on the side of the opening window that is closer to the external space than the infrared radiation section, a shade erected on the side of the opening window that blocks sunlight, and a switching mechanism that can switch between a state of sunlight transmission and a state of sunlight blocking.

5. The radiative cooling device according to claim 4, characterized in that the switching mechanism has a dimming panel capable of automatically switching between a transparent state in which sunlight is transmitted and an opaque state in which the transmission of sunlight is blocked, depending on whether it is day or night.

6. The radiative cooling device according to claim 4, characterized in that the switching mechanism has a shutter body that can automatically switch between an open state and a closed state of the opening window between day and night by a movement operation.

7. The radiative cooling device according to claim 4, characterized in that the switching mechanism has a light-shielding curtain that can automatically switch between an open state and a closed state of the opening window between day and night by winding and unwinding operations.

8. The radiative cooling device according to any one of claims 4 to 7, characterized in that the switching mechanism is accompanied by a power supply device having a solar panel that supplies operating power for switching between the light-transmitting state and the light-shielding state, a battery that stores the operating power, and a control unit that controls the timing of power supply for supplying operating power to the switching mechanism.

9. The emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, with the infrared radiation portion positioned on the side of the small hole that is to be cooled. The temperature rise suppression structure comprises: an infrared radiation portion having a substantially hemispherical radiation surface with a recess facing the partition wall; the small hole provided on or near a far-infrared focusing point located at a distance from the infrared radiation portion; a cylindrical heat dissipation duct inserted into the small hole; a far-infrared transparent plano-concave lens fitted to the end of the heat dissipation duct on the side of the cooling object, which parallelizes multiple far-infrared rays from the substantially hemispherical radiation surface and allows them to pass through the heat dissipation duct; and a far-infrared transparent duct insulation material fitted to the end of the heat dissipation duct on the side of the plano-concave lens that is to the external space. The radiative cooling device according to claim 2, characterized in that it has a conical infrared guide portion which covers the recess of the infrared radiation portion with a bottom opening and connects the upper opening to a small hole in the partition wall, thereby reflecting and concentrating multiple far-infrared rays emitted from the radiation surface with its inner circumferential surface and guiding them to the end on the cooling target side with the heat dissipation duct.

10. The emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, with the infrared radiation portion positioned on the cooling target side of the small hole, and the temperature rise suppression structure comprises: an infrared radiation portion having a substantially hemispherical radiation surface with a recess facing the partition wall side; the small hole provided on or near the far-infrared focusing point located at a distance from the infrared radiation portion; a cylindrical heat dissipation duct inserted into the small hole, having an oblique cut portion at its end facing the external space, and reflecting a plurality of far-infrared rays emitted from the radiation surface with its inner circumferential surface and releasing them into the external space from the oblique cut portion; and a far-infrared transparent duct insulation material fitted into the oblique cut portion of the heat dissipation duct. The radiative cooling device according to claim 2, characterized in that it has a conical infrared guide portion which covers the recess of the infrared radiation portion with a bottom opening and connects the upper opening to a small hole in the partition wall, thereby reflecting and concentrating multiple far-infrared rays emitted from the radiation surface with its inner circumferential surface and guiding them to the end on the cooling target side with the heat dissipation duct.

11. The emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, with the infrared radiation portion positioned on the cooling target side of the small hole, and the temperature rise suppression structure comprises an infrared radiation portion having a flat radiating surface facing the partition wall side, the small hole provided in a far-infrared light concentrating portion located at a distance from the infrared radiation portion, a cylindrical heat dissipation duct fitted into the small hole and having an oblique cut portion at its end facing the external space, which reflects a plurality of far-infrared rays emitted from the radiating surface with its inner circumferential surface and emits them into the external space from the oblique cut portion, and a far-infrared transparent duct insulation material fitted into the oblique cut portion of the heat dissipation duct, The radiative cooling device according to claim 2, characterized in that it has a composite parabolic infrared guide section which covers the flat portion of the infrared radiation section with a bottom opening and connects the upper opening to a small hole in the partition wall, thereby reflecting and concentrating multiple far-infrared rays emitted from the radiation surface with its inner circumferential surface and guiding them to the end on the cooling target side with the heat dissipation duct.

12. The radiant cooling device according to claim 1, characterized in that the heat collection promotion structure has an infrared radiation section formed by creating a heat receiving surface on the inside of a housing surrounding the heat-generating element to be cooled, into which heat from the heat-generating element flows, and creating the radiating surface on the outside of the housing.

13. The radiant cooling device according to claim 2 or 12, characterized in that the emission portion is a small hole that penetrates the partition wall in the thickness direction and has a smaller area than the infrared radiation portion, the infrared radiation portion is positioned on the cooling target side of the small hole, and the temperature rise suppression structure comprises a conical or composite parabolic concentrator with a bottom opening covering the radiating surface of the infrared radiation portion, which concentrates far-infrared rays emitted from the radiating surface to the vicinity of its apex, either directly or by internal reflection; an optical fiber portion to which one end of an optical fiber is connected to the apex of the concentrator, and the other end of the optical fiber is gathered to form an insulating optical fiber bundle; and the small hole is positioned spaced apart from the infrared radiation portion, with the concentrator and optical fiber portion in between, through which the concentrated far-infrared rays are emitted into the external space via the inserted optical fiber bundle.

14. The radiative cooling device according to claim 13, characterized in that the temperature rise suppression structure has a far-infrared transparent convex lens between the radiating surface of the infrared radiating unit and the bottom opening of the concentrator, which concentrates the far-infrared rays from the radiating surface to the top of the concentrator.

15. The radiative cooling device according to claim 13, characterized in that a radiator capable of emitting far-infrared rays with high emissivity is provided at the end of the optical fiber section.

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