Thermal insulation materials and thermal insulation windows

Abstract

A heat-insulating window according to the present invention is provided with: a pair of panels; a space sandwiched between the panels; a heat-insulating material that can fill the space; and a mechanism that can fill the space with the heat-insulating material and remove the heat-insulating material. The heat-insulating material is characterized by containing aerogel having a three-dimensional network structure, the skeleton of which is formed by clusters that are aggregates of primary particles, and containing fine particles having the three-dimensional network structure, the skeleton of which is formed by the primary particles. Such heat-insulating material has extremely high flowability and can be moved by liquid, thereby allowing filling and removal of the heat-insulating material into and from the space between the pair of panels. In addition, a heat-insulating member according to the present invention is provided with a cavity, the shape of which can be changed, and a heat-insulating material accommodated in the cavity. The heat-insulating material is a powder, has flowability, has volume retention performance that retains the volume before and after the change in the cavity shape, and moves inside the cavity as the cavity shape changes.

Description

Technical Field

[0001] The present invention relates to a heat insulating member and a heat insulating window, and in particular, it can be suitably used for a heat insulating member whose heat insulating portion can be changed, and further, it can be more suitably used for a heat insulating window capable of switching between a transparent state and a light shielding and heat shielding state.

Background Art

[0002] As attention to energy-saving houses as a measure against global warming increases, heat insulation of windows is extremely important. This is because it is necessary to suppress the intrusion of heat from the outside in summer, suppress the release of heat to the outside in winter, and further consider the balance with daylighting.

[0003] Patent Document 1 discloses a window unit capable of adjusting the amount of daylighting and heat insulation by filling and removing foamed resin particles in a hollow portion formed by sandwiching a transparent plate such as a double-glazed window. Heat insulation is enhanced by transporting foamed resin particles from a storage tank by an air flow and filling the hollow portion, and daylighting is enhanced by removing the foamed resin particles from the hollow portion by an air flow and recovering them in the storage tank. This document points out a problem that the foamed resin particles are rubbed against each other and charged when being transported by an air flow, and thus adhere to the transparent plate constituting the double-glazed window, and this problem is solved by applying an antistatic coating to the inner wall of the double-glazed window.

[0004] Patent Document 2 discloses a window that enables adjustment of the area of a portion that can transmit light. A gap is provided between a pair of glass panels, a lifter is disposed in this gap, and lightweight particles filled above the lifter are lowered to the lower end to obtain a light shielding state, and the lifter is raised to increase the transparent area and achieve daylighting.

[0005] Patent Document 3 discloses a double-glazed window configured to allow hydrophobic aerogel granules to be inserted into and removed from the internal space. The hydrophobic aerogel granules fall from the storage section and are filled into the window, and then collected in the storage section by a blowing mechanism. An embodiment is also introduced in which hydrophobic aerogel granules having a silica skeleton are used as a thermal insulation material, a transparent conductive film is formed on the inner surface of the double-glazed window, and the inner wall of the double-glazed window is charged to allow the hydrophobic aerogel to adhere.

[0006] Patent Document 4 discloses a light-shielding member in which aerogel particles are filled into a space sandwiched between two transparent panels. Although there is no mention of a mechanism for switching between a transparent state and a light-shielding / heat-shielding state, the results of a detailed analysis of the relationship between the particle size of the aerogel particles and the visible light transmittance are disclosed.

[0007] While thermal insulation and heat shielding are technical terms that should be clearly distinguished in professional contexts, they are used synonymously in this specification. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 5-86780 [Patent Document 2] Japanese Patent Application Publication No. 5-202681 [Patent Document 3] Japanese Patent Application Publication No. 11-30085 [Patent Document 4] Japanese Patent Publication No. 2018-178372 [Overview of the project] [Problems that the invention aims to solve]

[0009] As shown in Patent Documents 1 to 4, various windows have been proposed that insulate against heat by filling the gap between the double-glazed windows with insulating materials such as aerogel particles. The inventions disclosed in Patent Documents 1 to 3 have a mechanism that can switch between a state in which insulating materials such as aerogel particles are filled and a state in which they are removed, thereby controlling the balance between heat insulation and light transmission, but the control mechanism is complex. The double-glazed windows disclosed in Patent Documents 1 and 3 require an air supply fan or valve to move the particulate insulating material by airflow, and furthermore, a heater to prevent condensation and a transparent conductive film and control circuit to charge the inside of the window are provided. The double-glazed window disclosed in Patent Document 2 is equipped with an elevator to mechanically move the particulate insulating material. This is because insulating materials such as aerogel require a certain size, and a certain amount of physical force is required to move them.

[0010] The inventors of this invention have noticed that, in general insulating materials that constitute a container for keeping things cool or warm (including insulating building materials such as walls, floors, and roofs), no mechanism has yet been investigated or put into practical use that can switch between insulating and not insulating, and furthermore, adjust the insulating performance. This is thought to be because adjusting the insulating properties in an insulating material requires a complex mechanism similar to that considered in the prior art described above for windows.

[0011] The objective of the present invention is to provide an insulating member and an insulating window that have a simple mechanism for adjusting the thermal insulation state (the area to be insulated and the thermal insulation performance).

[0012] The means for solving these problems are described below, but other problems and novel features will become apparent from the description and accompanying drawings in this specification. [Means for solving the problem]

[0013] According to one embodiment of the present invention, the following applies:

[0014] That is, the heat-insulating window according to the present invention is a heat-insulating window provided with a pair of panels, a space sandwiched therebetween, a heat-insulating material capable of filling the space, and a mechanism capable of filling and removing the heat-insulating material into the space, and has the following features.

[0015] The heat-insulating material is made from an aerogel having a three-dimensional network structure in which a skeleton is formed by clusters which are aggregates of primary particles, and contains fine particles having a three-dimensional network structure formed by the primary particles as the skeleton.

[0016] The mechanism is a mechanism capable of changing the shape of the space in order to move the heat-insulating material.

[0017] The fine particles constituting the heat-insulating material according to the present invention may additionally have the feature that 50% or more of its volume is dispersed with the most frequent value in the particle diameter range of 0.1 μm or more and 1.0 μm or less.

[0018] Further, the heat-insulating member according to the present invention includes a cavity capable of changing its shape and a heat-insulating material housed in the cavity. The heat-insulating material is a powder and moves inside the cavity as the shape changes. Here, the cavity refers to a cavity inside the heat-insulating member that can store the heat-insulating material. For example, it is a cavity formed by being sandwiched between a pair of panels, or a bag capable of housing a heat-insulating material inside. In this specification, a pair of panels or a bag containing a heat-insulating material is referred to as a heat-insulating member, and the cavity capable of storing the heat-insulating material of the heat-insulating member is called a cavity, while the cavity for cold storage and heat preservation made using the heat-insulating member is called a container.

Effects of the Invention

[0019] The effects obtained by the above-described embodiment will be briefly described as follows.

[0020] That is, it is possible to provide a heat-insulating member and a heat-insulating window having a simple mechanism for adjusting the heat-insulating state (heat-insulating location and heat-insulating performance).

Brief Description of the Drawings

[0021] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a configuration example of a heat-insulating window according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing a configuration example of a heat-insulating window according to another embodiment of the present invention. [Figure 3] FIG. 3 is an explanatory view showing a comparison of the structures of general aerogel particles and fine particles having a skeleton formed by primary particles. [Figure 4] FIG. 4 is an explanatory view showing an example of the frequency distribution of the particle diameters of general aerogel granules, powders and fine powders obtained by pulverizing them, and fine particles having a skeleton formed by primary particles. [Figure 5] FIG. 5 is an explanatory view showing a method for measuring the dynamic angle of repose. [Figure 6] FIG. 6 is an explanatory view showing the measurement results of the dynamic angle of repose. [Figure 7] FIG. 7 is an explanatory view showing a method for measuring the volume change rate. [Figure 8] FIG. 8 shows the measurement results of the volume change rate. [Figure 9] FIG. 9 shows the measurement results of the change over time of the volume change rate. [Figure 10] FIG. 10 is a schematic cross-sectional view showing a configuration example of a heat-insulating container using the heat-insulating member of the present invention. [Figure 11] FIG. 11 is a schematic cross-sectional view showing another configuration example of a heat-insulating container using the heat-insulating member of the present invention. [Figure 12] FIG. 12 is a schematic cross-sectional view showing still another configuration example of a heat-insulating container using the heat-insulating member of the present invention. [Figure 13] FIG. 13 is a schematic cross-sectional view showing a configuration example of a heat-insulating window according to still another embodiment of the present invention.

Embodiments for Carrying Out the Invention

[0022] 1. Principle of Solution of the Present Invention The principle by which the above-mentioned problems can be solved by the present invention will be explained.

[0023] The inventors have invented a thermal insulation material characterized by using an aerogel having a three-dimensional network structure formed by clusters of primary particles as a raw material, and containing fine particles having a three-dimensional network structure formed by the same primary particles, and have filed a patent application for this material as Japanese Patent Application No. 2020-193892. This thermal insulation material is called TIISA (trademark application pending from Thermalytica Co., Ltd.). TIISA has a thermal conductivity equivalent to that of high-performance aerogel and a bulk density of 0.01 g / cm³. 3 It is less than one-tenth the size of typical aerogels. Therefore, it is a lightweight and high-performance thermal insulation material. Unlike typical aerogels, which have a framework formed of secondary particles, TIISA has a framework formed mainly of primary particles that make up the secondary particles. As a result, it consists of extremely fine particles, and more than 50% of its volume is dispersed with a mode of particle size between 0.1 μm and 1.0 μm.

[0024] Figure 3 is an explanatory diagram illustrating a comparison between the structures of general aerogel particles and microparticles whose framework is formed by primary particles. The three-dimensional network structure of general aerogel particles 13 is composed of secondary particles 12, which are clusters of primary particles 11 (Figure 3(a)), whereas the microparticles 14 of the present invention (e.g., TIISA microparticles) have a three-dimensional network structure formed with their primary particles 11 as the framework (Figure 3(b)).

[0025] Aerogels commonly available on the market are in granular form, and have a three-dimensional network structure with a framework composed of 12 secondary particles. Therefore, even if they are finely ground using a grinding device, the framework structure does not change. The experimental results are shown below. Figure 4 is an explanatory diagram showing an example of the frequency distribution of particle sizes for aerogel granules, aerogel powder, aerogel fine powder, and TIISA, which are fine particles with a framework formed by primary particles, from bottom to top. The aerogel granules are the same as the aerogel granules commonly available on the market. The aerogel powder was produced by grinding aerogel granules at 5000-7000 rpm for 2 minutes using a spin mix homogenizer SX08 manufactured by Mitsui Electric Seiki Co., Ltd. The aerogel fine powder was produced by grinding aerogel granules at 21000 rpm for 20 seconds using a STEALTH885 manufactured by Blendtec. The horizontal axis of Figure 4 represents particle size, and the vertical axis represents the frequency distribution of particle size. The vertical axis on the right shows the frequency, and the vertical axis on the left shows the cumulative value. Figure 4 shows the observation results using a laser diffraction particle size distribution (PSD) analyzer. In this specification, particle size is explained assuming PSD measurement. However, in PSD measurement, not only the diameter of the particle itself but also the aggregation of particles is observed as particle size, so the true particle size is likely to be smaller than the measured value. If there is a difference in particle size depending on the measurement method, please understand it by converting. More specifically, Figure 4 is the particle size distribution measured using a laser diffraction particle size distribution analyzer SALD-2300 manufactured by Shimadzu Corporation. Particle size distribution is an index that shows what size (particle diameter) of particles and in what proportion (relative particle amount with the whole being 100%) are contained in a sample group of particles to be measured, and the dimension (order) of the particle amount is volume-based.

[0026] Generally available aerogel granules have a single peak in relative particle amount with an average particle size of approximately 400 μm (bottom of Figure 4). When these aerogel granules are pulverized using the apparatus described above, the aerogel powder has an average particle size of approximately 90 μm, and the aerogel fine powder has an average particle size of approximately 50 μm, but each has only one peak in relative particle amount (third and second rows). In contrast, TIISA has a first peak with an average particle size of approximately 20 μm and a second peak with an average particle size of approximately 0.3 μm, with the relative particle amount being 21.2% for the first peak with an average particle size of approximately 20 μm and 78.8% for the second peak with an average particle size of approximately 0.3 μm. This is because the first peak with an average particle size of approximately 20 μm is composed of fine particles with a three-dimensional network structure whose framework is composed of 12 secondary particles, while the second peak with an average particle size of approximately 0.3 μm is composed of fine particles with a three-dimensional network structure whose framework is formed by primary particles.

[0027] Conventional aerogels have a three-dimensional network structure whose framework is composed of secondary particles, making it difficult to produce fine particles with a diameter of 10 μm or less, no matter how much the grinding conditions are improved. To produce fine particles with a three-dimensional network structure formed from primary particles, a fundamental change in the manufacturing method is necessary, unlike the normal aerogel manufacturing process, including significant changes not only to the grinding conditions but also to the aging conditions, as described in Japanese Patent Application No. 2020-193892.

[0028] The inventors have newly discovered, through experiments described below, that TIISA exhibits high fluidity and volume retention performance comparable to that of liquids. Dynamic angle of repose and volume change rate were adopted as indicators to represent fluidity and volume retention performance, respectively. For example, the angle of repose used in Patent Document 4 is the static angle of repose, which is suitable for measurements of powders but was found not to be necessarily appropriate for representing the fluidity of fluids. The inventors also realized that although the insulating material is subjected to forces from the outside as it flows, i.e., moves, its volume does not change as a result, i.e., volume retention performance is also an important characteristic.

[0029] [Dynamic Angle of Rest] Figure 5 is an explanatory diagram (schematic cross-sectional view) showing the method for measuring the dynamic angle of repose. The dynamic angle of repose measuring device 90 is configured such that the sample 91 is placed in a cylindrical glass container 92, rotated on two rotating pipe-shaped rollers 93, and the sample 91 can be observed from the bottom side of the glass container 92. When the sample 91 is not rotating, its surface is horizontal, and as the rotation speed increases, the surface tilts, and the angle θ from the horizontal is measured as the dynamic angle of repose.

[0030] Figure 6 is an explanatory diagram showing the measurement results of the dynamic angle of repose. The top row is water, and the others, as in Figure 4, are shown in order from the bottom row: aerogel granules, aerogel powder, aerogel fine powder, and TIISA, which are microparticles formed by a framework of primary particles, at rotation speeds of 16 rpm, 32 rpm, and 48 rpm. The surface shape is not flat as shown by the dashed line in Figure 6, but when the angle θ is quantified by linear approximation, at a rotation speed of 48 rpm, the angle is 6° for water, 50°, 20°, and 26° for aerogel granules, aerogel powder, and aerogel fine powder, respectively, while TIISA was 6-15°. The dynamic angle of repose is largest for aerogel granules, and smaller for TIISA than for aerogel powder and aerogel fine powder, indicating that it is close to that of water.

[0031] [Volume change rate] The volume change rate is an indicator adopted by the inventors in this invention as one of the indicators showing the fluidity of TIISA, and is measured by the following method.

[0032] Figure 7 is an explanatory diagram showing the method for measuring the rate of volume change. The sample 91 is placed in a transparent, cylindrical elastic tube 96 and compressed from both sides by compression blocks 97. The upper part of Figure 7 is a cross-sectional view seen from the side, and the lower part is a cross-sectional view seen from above of the area xx where the sample is compressed. From the initial state, the width of the compression blocks 97 is narrowed to compress the sample, and then it is returned to its original state (called the recovery state). The elastic tube 96 is a pipe-shaped container with a diameter of 12 mm and a wall thickness of 0.25 mm. In the compressed state, the shorter side in the direction of compression becomes 6 mm and the longer side in the vertical direction becomes 16 mm, but in the recovery state it returns to its original diameter of 12 mm. The height h of the sample 91 in the initial state. ITherefore, in a compressed state, the height is h H In the recovered state, the height h L This is the result. In a perfect fluid with no change in volume, the height of the recovery state is h. L The initial height is h I It will recover.

[0033] Figure 8 shows the measurement results of the volume change rate. The horizontal axis represents the depth of compression by the compression block 97, and h represents the change in surface height from the initial state. H -h I This graph has the vertical axis representing the pressure. The change in surface height from the initial state is roughly proportional to the depth of compression, although not strictly proportional. The maximum change in surface height for water, a perfect fluid, was 15 mm, while for TIISA it was 13 mm, for aerogel fine powder 6 mm, for aerogel powder 5 mm, and for aerogel granules 2 mm. When the change in water is set to 1, the relative values ​​of the changes in TIISA, aerogel fine powder, aerogel powder, and aerogel granules were 0.87, 0.40, 0.33, and 0.13, respectively.

[0034] Figure 9 shows the measurement results of the change in volume rate over time. The number of times the compression and recovery states were repeated is plotted on the logarithmic horizontal axis, and the rate of change of the volume of sample 91 from its initial state is plotted on the vertical axis. Similar to how the volume of water, a perfect fluid, does not change even after repeated compression and recovery (volume change rate = 0%), the volume change rate of TIISA also did not change even after 100 compression and recovery cycles (volume change rate = 0%). On the other hand, the volume change rates of aerogel granules were 21%, 53%, and 63% for 1, 10, and 100 compression and recovery cycles, respectively. The volume change rates of aerogel powder were 32%, 42%, and 53% for 1, 10, and 100 compression and recovery cycles, respectively. The volume change rates of aerogel fine powder were 42%, 53%, and 84% for 1, 10, and 100 compression and recovery cycles, respectively. All of these changes were in the direction of increasing volume compared to the initial state. This is thought to be the result of the three-dimensional network structure being partially destroyed by repeated compression and recovery, leading to larger gaps. From these experimental results and discussion, it was found that commercially available aerogels, whether in granular form or crushed, undergo irreversible volume changes with compression and recovery.

[0035] Furthermore, it was found that TIISA can be made extremely hydrophobic. (TIISA can also be processed to be hydrophilic.) The inventors focused on the fact that TIISA's high fluidity is comparable to that of a liquid, and realized that it can be moved by a liquid rather than by air as described in Patent Documents 1-3. They also found that, taking advantage of its high hydrophobicity, the liquid can be water.

[0036] If a liquid, particularly water, is used as the medium, it is relatively easy to contain it to suppress diffusion and leakage, and it is also easy to move. If the medium is a liquid mainly composed of water, it can form a clear interface without mixing with TIISA having high hydrophobicity. Furthermore, the mechanism for containing and moving the liquid (water) as the medium can be a simple elastic cavity, which can be made into an extremely simple mechanism. By compressing such an elastic cavity by applying pressure or the like to extrude the medium, TIISA can be moved to a desired position accordingly, and conversely, it can be returned to its original position by releasing it from the compressed state.

[0037] Note that the fine particles that can be used as a heat insulating material are described as "TIISA", and there are also places in this specification where "TIISA" is used to describe other material substances of the heat insulating material. Needless to say, the same solution principle applies to materials having equivalent fluidity and volume retention performance.

[0038] By utilizing this principle, a mechanism for moving the heat insulating material to a desired position can be simply configured. In particular, when applied to a double window, a mechanism for switching heat insulation and daylighting can be simply configured.

[0039] 2. Outline of Embodiment First, an outline of a typical embodiment disclosed in the present application will be described. The reference signs in the drawings referred to with parentheses in the outline description of the typical embodiment merely exemplify those included in the concept of the components to which they are attached.

[0040] 〔1〕<Heat Insulating Window Using TIISA as Heat Insulating Material> A typical embodiment of the present invention is a heat insulating window (10) including a pair of panels (7), a space (8) sandwiched between the pair of panels, a heat insulating material (1) that can be filled in the space, and a mechanism (2 to 6) that can move the heat insulating material into and out of the space for filling and removal, and has the following characteristics.

[0041] The heat insulating material uses an aerogel (13) having a three-dimensional network structure in which a framework is formed by clusters (12) that are aggregates of primary particles (11), and includes fine particles (14) having a three-dimensional network structure in which a framework is formed by the primary particles (11).

[0042] Thereby, it is possible to provide a heat insulating window having a simple mechanism for adjusting heat insulation and daylighting. Here, the mechanism for moving the heat insulating material can be realized in various modes. Since the heat insulating material has high fluidity and volume retention performance comparable to that of a liquid, as shown in [3] described later, a mechanism for moving the heat insulating material using a liquid as a medium may be used, or by adjusting the volume of the space (cavity) that houses the heat insulating material in the same manner as a liquid, a mechanism for applying force to the heat insulating material itself to move it may also be used.

[0043] Note that "a pair of panels" means "at least a pair of panels", and the heat insulating window may be a multi-window including a plurality of panels (7) and having a plurality of spaces (8). At this time, the heat insulating material may be filled / removed in the same manner in the plurality of spaces, or may be filled / removed independently in each space, or a space where filling / removing is not performed may be included.

[0044] 〔2〕<TIISA's feature: particle size> In the heat insulating window of [1], the fine particles constituting the heat insulating material are characterized in that at least 50% of their volume is dispersed with a most frequent value in a particle size range of 0.1 μm or more and 1.0 μm or less.

[0045] With this feature, high fluidity of the heat insulating material is ensured.

[0046] 〔3〕<Mechanism for moving the heat insulating material using a liquid as a medium> In the heat insulating window of [1] or [2], the mechanism is a mechanism capable of moving a liquid in contact with the heat insulating material in order to move the heat insulating material.

[0047] This makes it possible to provide an insulated window with a simple mechanism for adjusting insulation and natural light. By employing a mechanism that uses a liquid as a medium to move the insulation material, it is possible to utilize a mechanism that is widely used to move the liquid while suppressing liquid leakage.

[0048] [4] <The medium used to move the insulation material is water> The insulating window of [3] is characterized in that the liquid mainly consists of water.

[0049] This allows for the construction of a low-cost mechanism for moving the insulation material.

[0050] [5] <Insulation filling / Air switching> In the insulated window according to any one of (1) to (4), the mechanism comprises an elastic cavity (4) on the lower side of the space capable of accommodating the insulating material (and the liquid), and a compression mechanism (3) capable of increasing or decreasing the volume of the elastic cavity.

[0051] The mechanism moves the thermal insulation material from the elastic cavity to the space by reducing the volume of the elastic cavity with the compression mechanism, and moves the thermal insulation material from the space to the elastic cavity by increasing the volume of the elastic cavity with the compression mechanism.

[0052] This allows for the simple construction of a mechanism for moving the insulation material.

[0053] [6] <Insulation material filling / Switching to liquid (water)> In the insulated window of [3] or [4], the mechanism comprises an upper elastic cavity (5) capable of housing the insulating material above the space, a lower elastic cavity (4) capable of housing the liquid below the space, and a compression mechanism (3) capable of increasing or decreasing the volume of the lower elastic cavity.

[0054] The mechanism moves the liquid from the elastic cavity to the space by reducing the volume of the lower elastic cavity by the compression mechanism, moves the heat insulating material from the space to the upper elastic cavity, moves the liquid from the space into the lower elastic cavity by increasing the volume of the lower elastic cavity by the compression mechanism, and moves the heat insulating material from the upper elastic cavity to the space.

[0055] Thereby, a mechanism for moving the heat insulating material can be simply configured.

[0056] 〔7〕<Heat insulating member composed of a heat insulating material with fluidity> A typical embodiment of the present invention is a heat insulating member (20) including a cavity (21) capable of changing its shape and a heat insulating material (1) accommodated in the cavity, wherein the heat insulating material is a powder and moves within the cavity as the shape changes.

[0057] Thereby, a heat insulating member having a simple mechanism for adjusting heat insulation can be provided. A heat insulating member is a member constituting a heat insulating container or the like, and can be a member constituting a heat insulating building material such as the above-described heat insulating window, or a member constituting a heat insulating container or the like. The cavity may have a gap sandwiched between side walls such as a pair of panels, and as long as the heat insulating material can be accommodated in the gap, its shape is arbitrary. Further, the change in shape includes any change such as a change in the volume of the cavity, a change in the shape for changing the place where the heat insulating material is held, a change in the thickness of the heat insulating material, etc.

[0058] 〔8〕<Heat insulating member using TIISA as a heat insulating material> In the heat insulating member of 〔7〕, the heat insulating material uses an aerogel (13) having a three-dimensional network structure in which a cluster (12) that is an aggregate of primary particles (11) forms a skeleton, and includes fine particles (14) having a three-dimensional network structure in which the primary particles form a skeleton.

[0059] This characteristic ensures that the insulation material has high fluidity and volume retention capabilities.

[0060] [9] <Insulating material that uses insulating material with fluidity and volume retention properties> In the thermal insulation member of [7], the thermal insulation material is fluid and has volume-retaining properties such that its volume is maintained before and after the change in the shape of the cavity.

[0061] Any insulating material with high fluidity and volume retention performance can be used in the insulating member of the present invention, even if it does not possess the characteristics of [7] above. This applies to all embodiments, including the insulating windows of [1] to [5] above.

[0062]

[10] <Cavity decompression> In the thermal insulation member of [7] or [8], the pressure inside the cavity is lower than the outside air pressure.

[0063] This significantly reduces the thermal conductivity of the insulating material (improving its thermal insulation performance). The improvement in thermal insulation performance is particularly pronounced in [7].

[0064]

[11] <Filling cavities with a gas that has a lower thermal conductivity than air> In the insulating member of [7] or [8], the cavity is filled with a gas that has a lower thermal conductivity than air (for example, carbon dioxide).

[0065] This makes it possible to lower the thermal conductivity of the insulating material (improve the insulating performance). After depressurizing as described in [9] above, it is easier to maintain the filled state for a longer period of time than maintaining the depressurized state. Furthermore, it is easy to combine with the following

[11] to

[14] .

[0066]

[12] <Movement of insulating material using a liquid as a medium> In the thermal insulation member of [7], the cavity further contains a liquid (2) that is mutually exclusive with the thermal insulation material. Here, mutual exclusivity is the opposite of affinity and means the property of not being able to mix, and corresponds to hydrophobicity, for example, the property of a substance that does not mix with water.

[0067] This allows for the simple construction of a mechanism for moving the insulation material.

[0068]

[13] <Movement of insulating material using water as a medium> In the thermal insulation member of [7], the thermal insulation material is hydrophobic, and the cavity further contains water (2).

[0069] This allows water to be used as a medium for moving the insulation material, and the mechanism can be easily constructed.

[0070]

[14] <Insulation material transfer mechanism> In the thermal insulation member of [7], the cavity has one or more pairs of panels (21i, 21w) and a thermal insulation material storage section (23), and each of the one or more pairs of panels has a gap (22) on the inside in which the thermal insulation material can be accommodated. The thermal insulation material storage section accommodates the thermal insulation material, and the volume of the space continuous with the gap changes, thereby pushing the thermal insulation material into the gap of the panel or recovering it from the gap of the panel.

[0071] This allows the insulation material to be moved between the gaps in the paired panels and the insulation storage area, thereby adjusting the insulation performance of the panel section.

[0072]

[15] <Mechanism for transporting insulating material using a liquid medium> In the thermal insulation member of

[12] , the cavity has one or more pairs of panels (21i, 21w), a thermal insulation material storage section (23), and a liquid storage section (24), and each of the one or more pairs of panels has a gap (22) on the inside in which the thermal insulation material can be accommodated.

[0073] The insulation material storage section has a space continuous with the gap, and the insulation material can be stored in the space. The liquid storage section stores the liquid, and the liquid is moved by a change in the volume of the space continuous with the gap, thereby pushing the insulation material into the gap of the panel or recovering it from the gap of the panel.

[0074] This allows the insulation material to be moved between the gaps in the paired panels and the insulation material storage section, thereby adjusting the insulation performance of the panel section. The liquid storage section (24) is a volume adjustment mechanism that uses liquid as a medium. Because a liquid (e.g., water) is used as a medium for moving the insulation material, it has the effect of suppressing leakage even if there are moving parts, and increases the degree of freedom in designing the volume adjustment mechanism.

[0075] 3. Details of the Embodiment The embodiments will be described in more detail.

[0076] [Embodiment 1] Figure 1 is a schematic cross-sectional view showing an example of the configuration of an insulated window 10 according to one embodiment of the present invention.

[0077] The insulated window 10 of this embodiment comprises a pair of panels 7, a space 8 sandwiched between them, an insulating material 1 that can be filled into the space 8, and mechanisms 2 to 6 that can move the insulating material 1 to fill the space 8 and move it out of the space 8 to remove it. The insulating material 1 is made from an aerogel 13 having a three-dimensional network structure in which the framework is formed by clusters 12 which are aggregates of primary particles 11, and contains fine particles 14 having a three-dimensional network structure in which the framework is formed by the primary particles 11. The above mechanism is a mechanism that can move the liquid 2 that is in contact with the insulating material 1 in order to move the insulating material 1. By using liquid 2 as the medium for moving the insulating material 1, sealing becomes easier than using a gas (air), and there is an advantage that the volume changes almost when pressure is applied, so the applied pressure can be directly transmitted to the insulating material 1 and moved. This makes it possible to provide an insulated window 10 with a simple mechanism for adjusting insulation and natural light.

[0078] The fine particles 14 constituting the thermal insulation material 1 preferably have a frequency distribution of particle size with a mode (peak) of dispersion of 1.0 μm or less, and it is even more preferable that 50% or more of the volume is dispersed with a mode of particle size between 0.1 μm and 1.0 μm. Since the thermal insulation material 1 has this characteristic, its high fluidity is ensured.

[0079] The thermal insulation material 1 is preferably a powder composed of fine particles with the following characteristics regarding particle size distribution, but it is not limited to this; any material with similar fluidity (dynamic angle of repose) and volume retention performance is acceptable. For example, regarding the dynamic angle of repose, referring to the experimental results shown in Figure 6, it can be seen that a thermal insulation material with a dynamic angle of repose three to four times that of water can be used. It is also desirable that the volume retention performance is similar to that of a liquid. The mechanism for moving the thermal insulation material is optimally designed using the force applied to move the thermal insulation material, the frequency of movement, and the lifespan of the thermal insulation material as parameters.

[0080] In this insulated window 10, it is preferable that the liquid 2 is a liquid mainly composed of water. By making the insulating material 1 a material that is highly hydrophobic and, as described above, highly fluid, it does not mix with the liquid 2 which is mainly composed of water, a clear interface is formed, and the liquid 2 can move smoothly. In addition, by using water as the liquid 2, the mechanism for moving the insulating material can be constructed at low cost.

[0081] The mechanism for moving the insulation material 1 can be configured as shown in Figure 1, for example. In the insulated window 10, this mechanism has a lower elastic cavity 4 and an upper elastic cavity 5 on the lower and upper sides of the space 8 sandwiched between transparent panels 7, such as glass, and is composed of a frame that supports the panels 7 and houses the lower elastic cavity 4 and upper elastic cavity 5, respectively. The lower frame 6 houses a compression mechanism 3 that can control the volume of the lower elastic cavity 4. As shown in Figure 1(a), the lower elastic cavity 4 has a volume that can accommodate the insulation material 1 and liquid 2 within the lower frame 6. At this time, the space 8 is filled with air, and the insulated window 10 is transparent, transmitting visible light. The upper elastic cavity 5 has the minimum volume. The volume of the lower elastic cavity 4 decreases when pressure is applied from the compression mechanism 3 provided around it, pushing the insulation material 1 into the space 8. The space 8 becomes filled with the insulation material 1 and is insulated from heat. At this time, the upper elastic cavity 5 expands to accommodate the air pushed out from the space 8. This makes it possible to easily construct a mechanism for moving the insulation material.

[0082] The lower elastic cavity 4 is bonded to the panel 7 at its lower end, and the upper elastic cavity 5 is bonded to the panel 7 at its upper end, sealing the space 8 to prevent the insulation material 1 from leaking out and the liquid 2 from volatilizing. The lower and upper elastic cavities 4 and 5 can be made of, for example, rubber or latex. The lower elastic cavity 4 is preferably configured to expand to its maximum volume by the weight of the liquid 2 it contains. The upper elastic cavity 5 is preferably configured to expand naturally by containing air and to contract naturally as the space 8 is depressurized as the liquid 2 returns to the lower elastic cavity 4. The compression mechanism 3 for compressing the lower elastic cavity 4 can be, for example, a mechanism that transmits the pressure applied from outside the frame either directly or by amplifying the displacement using gears.

[0083] The mechanism for moving the thermal insulation material 1 can be implemented in various forms different from that of this embodiment 1. For example, instead of the lower elastic cavity 4, a cavity for housing the thermal insulation material 1 can be provided at the bottom of the space 8 sandwiched between a pair of panels 7, and the thermal insulation material 1 can be moved into the space 8 by injecting the liquid 2, which is the medium, into the cavity. This is effective because, when the panels 7 are large, the volume of thermal insulation material 1 to fill the space 8 is large, and the power required to move the thermal insulation material 1 into the space 8 is large, the liquid 2 can be injected using energy such as electricity.

[0084] For example, the lower elastic cavity 4 can be configured to extend to the left and right window frames. By effectively utilizing the volume of the window frame that contains the liquid (water) 2, the window frame can be made smaller. Also, by appropriately balancing the water level when the liquid (water) 2 is contained in the left and right window frames, the weight of the liquid (water) 2 contained in the left and right window frames can be used as a force to push up the insulation material 1 from inside the lower frame, allowing the insulation material 1 to be moved with little force.

[0085] Although the gas filling space 8 was described as air, it can be replaced with a gas with lower thermal conductivity, such as carbon dioxide. This can suppress the decrease in heat shielding performance while the material is transparent.

[0086] [Embodiment 2] Figure 2 is a schematic cross-sectional view showing an example of the configuration of an insulated window 10 according to another embodiment of the present invention. Basically, it has the same configuration as the insulated window 10 of Embodiment 1 shown in Figure 1, but the lower elastic cavity 4 has a volume that can accommodate the liquid 2 within the lower frame 6, and the upper elastic cavity 5 has a volume that can accommodate the insulating material 1 within the upper frame 6. When the lower elastic cavity 4 contains the liquid 2 and the insulating material 1 fills the space 8, the insulated window 10 enters a heat-shielding state (Figure 2(a)). When the lower elastic cavity 4 is compressed, the liquid 2 is pushed out into the space 8, and the upper elastic cavity 5 contains the insulating material 1, it becomes transparent (Figure 2(b)). This explanation naturally assumes that the liquid 2 is transparent. By making the liquid 2 semi-transparent to the same degree as the insulating material 1, the heat-shielding performance can be controlled without changing the transparency and therefore without affecting the amount of light entering the room. It is also possible to make the liquid 2 more opaque than the insulating material 1. Even with such embodiments, a mechanism for moving the insulating material can be easily constructed.

[0087] By using water for liquid 2, the construction can be made at a lower cost. If panel 7 is made of a hydrophilic material such as glass, the inner wall of panel 7 will become wet when liquid (water) 2 is discharged, but since the space 8 is filled with translucent insulation material 1 and the window is translucent, the aesthetics will not be compromised.

[0088] Furthermore, the detailed embodiments and various modifications described in Embodiment 1 can also be applied to Embodiment 2.

[0089] [Embodiment 3] Both Embodiments 1 and 2 are mechanisms (4-6) configured using liquid (water) 2 as a medium to move the heat insulating material 1, but the mechanism for moving the heat insulating material 1 can be realized in various other forms.

[0090] Figure 13 is a schematic cross-sectional view showing an example of the configuration of an insulated window 10 according to yet another embodiment of the present invention. It is basically the same configuration as the insulated window 10 of embodiments 1 and 2 shown in Figures 1 and 2, but it uses a mechanism that applies force to the insulation material 1 itself to move it, rather than using a liquid (water) 2 as a medium. Specifically, the lower elastic cavity 4 has a volume that can accommodate the insulation material 1 within the lower frame 6, and the upper elastic cavity 5 has a volume that can accommodate the air pushed out by the insulation material 1 within the upper frame 6. Other configurations are the same as in embodiments 1 and 2, so redundant explanations are omitted.

[0091] When the lower elastic cavity 4 is compressed, the insulating material 1 contained within is pushed out and filled into the space 8, causing the insulating window 10 to enter a heat-shielding state (Figure 13(a)). At this time, any gas such as air that was in the space 8 is further pushed out, causing the upper elastic cavity 5 to expand within the frame 6. On the other hand, when the lower elastic cavity 4 is released from compression and expands, and the insulating material 1 that was pushed out into the space 8 returns to be contained within the lower elastic cavity 4, it becomes transparent (Figure 13(b)). In this way, a mechanism can be constructed to move the insulating material 1 by directly applying force to it. The detailed embodiments and various modifications described in Embodiment 1 can also be applied to Embodiment 3. Embodiment 3 is an example in which cavities 4 and 5 are formed from elastic material, but it is not necessary to use elastic material for cavities 4 and 5 as long as their volume can be adjusted.

[0092] Furthermore, this third embodiment can be positioned as an embodiment in which the fourth embodiment, described later, is applied to the insulated window 10. That is, it is an insulated window comprising a cavity whose shape can be changed and an insulating material housed in the cavity, wherein the insulating material is a powder that moves within the cavity in accordance with the change in the shape of the cavity. In this case, the powder insulating material is required to have high fluidity, and it is even more preferable if it has volume retention performance comparable to that of a liquid. In this case, various modifications described in the fourth embodiment can also be applied to the insulated window 10 of this third embodiment. For example, although not shown in the illustration, an insulated window can be configured in which the insulating performance can be adjusted by adjusting the spacing (gap) between a pair of panels 7, following the example configuration shown in Figure 12.

[0093] [Embodiment 4] Embodiments 1, 2, and 3 are examples of applying the present invention to an insulated window 10, but the present invention can be applied to more general insulated members. That is, a more general embodiment of the present invention is an insulated member comprising a cavity whose shape can be changed and an insulated material housed in the cavity, wherein the insulated material is a powder that moves within the cavity in accordance with the change in the shape of the cavity. In this case, the powdered insulated material is required to have fluidity comparable to that of a liquid, and it is even more preferable if it has volume retention performance comparable to that of a liquid. This makes it possible to provide an insulated member with a simple mechanism for adjusting the insulation.

[0094] A suitable material for thermal insulation is TIISA. TIISA is a powder made from aerogel 13, which has a three-dimensional network structure formed by clusters 12, which are aggregates of primary particles 11, and contains fine particles 14, which also have a three-dimensional network structure formed by the primary particles 11. This structure allows TIISA to achieve the aforementioned fluidity and volume retention performance required for thermal insulation.

[0095] The cavity should be reduced to a pressure lower than the ambient air pressure. This significantly reduces the thermal conductivity of the insulating material (improving its thermal insulation performance). The improvement in thermal insulation performance is particularly pronounced when TIISA is used as the insulating material. With TIISA, the skeleton accounts for less than 1% of the total volume, and convection is suppressed by reducing the pressure by exhausting air from the remaining 99% or more of the space (gaps). Because the contribution of the space (gaps) to thermal conductivity is large, the improvement in thermal insulation performance by exhausting is remarkable. On the other hand, with conventional aerogel, the proportion of the skeleton (solid) to the total volume is high at about 5%, and the contribution of the skeleton (solid) to thermal conductivity is large, so even if convection is suppressed by exhausting the gaps, the improvement in thermal insulation performance is relatively small.

[0096] Alternatively, the cavity may be filled with a gas with lower thermal conductivity than air (e.g., carbon dioxide). This can lower the thermal conductivity of the insulating material (improving its insulating performance). After depressurizing as described above, it is easier to maintain the filled state for a longer period than maintaining the depressurized state. Furthermore, when a liquid (e.g., water) is used as a medium for moving the insulating material, as in the example shown in Figure 11, a gas with lower thermal conductivity (e.g., carbon dioxide) is more appropriate than the depressurized state described above.

[0097] Figure 10 is a schematic cross-sectional view showing one example of the configuration of an insulated container 20 using an insulating material according to this embodiment. The insulated container 20 is composed of an insulating material surrounding the perimeter. Specifically, the container 20 comprises side walls composed of cavities with gaps 22 sandwiched between an inner wall 21i and an outer wall 21w, a top cavity 21c, and a cavity at the bottom that constitutes an insulating material storage section 23. The top cavity 21c is filled with insulating material 1. A continuous space is formed between the gaps 22 sandwiched between the inner wall 21i and the outer wall 21w and the insulating material storage section 23, and the insulating material 1 is filled into this space. The insulating material storage section 23 is configured to change its volume, and by reducing its volume, the insulating material 1 inside is sent into the gaps 22 sandwiched between the inner wall 21i and the outer wall 21w, and by returning the volume to its original state, the insulating material 1 is recovered from the gaps 22 into the insulating material storage section 23.

[0098] The mechanism for changing the volume of the heat material storage section 23 may consist, for example, of an outer cylinder 27, a piston 28, and an operating rod 29 for pushing in or pulling out the piston 28. To prevent the heat insulating material 1 inside the heat material storage section 23 from entering the contact area between the outer cylinder 27 and the piston 28, a bag made of a flexible sheet such as latex (not shown) may be tightly attached from the tip of the outer cylinder 27 to the tip of the piston 28, or the inner and outer spaces may be separated.

[0099] The portion of the side wall where the insulation material 1 is filled into the gap 22 has high thermal insulation performance, while the portion where it has not reached has low thermal insulation performance. For example, the insulation material 1 can be selectively moved to areas where high thermal insulation performance is required, such as when there is a large temperature difference between the inside and outside. It can also be said that the thermal insulation performance of the entire side wall is controlled by the size of the area that the insulation material 1 reaches and fills.

[0100] Figure 11 is a schematic cross-sectional view showing another configuration example of an insulated container 20 using the insulated material according to this embodiment. This example of the insulated container 20 differs from the insulated container 20 in Figure 10 in that the bottom cavity is composed of an insulated material storage section 23 and a liquid storage section 24. Other configurations are the same as those of the insulated container 20 in Figure 10, so their explanation is omitted. The mechanism for adjusting the volume of the bottom cavity can be configured similarly to the mechanism for changing the volume of the heat material storage section 23 shown in Figure 10, but the bottom cavity contains liquid 2 in addition to the insulated material 1, and when the volume changes due to this mechanism, it is the liquid 2 that is directly moved, and the insulated material 1 is pushed and moved by the liquid 2. The liquid 2 is exclusive to the insulated material 1, that is, the liquid 2 is made of a material such that it does not mix with the insulated material 1 and a clear interface is formed. For example, if TIISA is used as the insulated material 1, the liquid 2 should be a liquid mainly composed of water. Because TIISA has extremely high hydrophobicity, it can be moved in accordance with the change in volume through a clear interface without mixing with water. By introducing liquid (water) 2 into the bottom cavity, known means of suppressing water leakage can be employed even when a volume adjustment mechanism such as an outer cylinder 27 and a piston 28 is provided. In other words, since a liquid (e.g., water) is used as a medium for moving the insulating material, it is possible to suppress leakage even if there are moving parts, and this increases the degree of freedom in designing the volume adjustment mechanism.

[0101] Figure 12 is a schematic cross-sectional view showing yet another configuration example of an insulated container using the insulating material according to this embodiment. In the configuration examples shown in Figures 10 and 11, a volume adjustment mechanism is provided in the bottom cavity, but the insulation performance is adjusted by changing the thickness of the insulating material 1 filled in the side wall cavity. The side wall cavity is made up of a gap sandwiched between the inner wall 21i and the outer wall 21w. The bottom of the container 20 has a double structure of a floor surface 21f and a bottom surface 21b, and the insulating material 1 is filled in the gap. The cavity 21c of the lid is configured such that the gap sandwiched between the inner wall 21i and the outer wall 21w is continuous with the space, and the insulating material 1 can move freely. By widening the outer wall 21w outward, the gap sandwiched between the inner wall 21i and the outer wall 21w becomes maximum, and the insulation performance is maximized (Figure 12(a)). By pushing the outer wall 21w toward the inner wall 21i and narrowing the gap, the filled insulation material 1 is pushed out into the cavity 21c of the canopy, and the thickness of the insulation material 1 filled into the cavity of the side wall becomes thinner, thus reducing the insulation performance (Figure 12(b)). The cavity 21c of the canopy should be inclined inward toward the gap in the side wall. The angle of inclination should be such that the insulation material 1 moves into the gap in the side wall due to its own weight.

[0102] Adjusting thermal insulation performance has various potential applications. For example, liquid hydrogen tanks used to supply hydrogen to fuel cell vehicles require proper internal pressure management. If the internal pressure is too high, the tank needs to be vented to prevent rupture, resulting in the wasteful disposal of hydrogen. On the other hand, if the internal pressure is too low, it becomes impossible to properly fill the fuel cell vehicle with hydrogen from the tank. Similar internal pressure adjustment is also necessary for tankers that transport liquid hydrogen over long distances.

[0103] Although the present inventor's invention has been specifically described above based on embodiments, it goes without saying that the present invention is not limited thereto and can be modified in various ways without departing from its essence. [Industrial applicability]

[0104] The present invention can be suitably used in thermal insulation members in which the location of insulation can be changed, and can be suitably applied to thermal insulation windows that can switch between a transparent state and a light-blocking / heat-shielding state. [Explanation of symbols]

[0105] 1. Insulation 2 Liquid (water) 3. Compression mechanism 4 Lower elastic cavity 5. Upper elastic cavity 6th slot 7 Panels 8 Space 10. Insulated windows 11 Primary particles 12. Secondary particles (collections of primary particles, clusters) 13. Aerogel particles (particles in which a framework has been formed by secondary particles) 14. Microparticles whose framework is formed by primary particles (e.g., TIISA) 20 Insulated containers 21 Cavity 21i, 21w, 21f, 21b: Inner wall, outer wall, floor, and bottom of an insulated container. 21c Cavity in the lid portion of an insulated container 22 Gap (space) 23 Insulation storage section 24. Liquid storage compartment, volume adjustment mechanism using liquid as a medium. 27 Outer cylinder 28 pistons 29 Operation rod 90 Dynamic Angle of Repose Measurement Device 91 samples 92 Glass containers 93 Rollers 96 Elastic tube 97 Compression Block

Claims

1. An insulated window comprising a pair of panels, a space sandwiched between the pair of panels, an insulating material that can be filled into the space, and a mechanism that allows the insulating material to be moved to fill the space and moved out of the space for removal, The aforementioned thermal insulation material is made from an aerogel having a three-dimensional network structure in which a framework is formed of secondary particles, which are aggregates of primary particles, and contains fine particles having a three-dimensional network structure in which a framework is formed of primary particles generated when the secondary particles are broken down. The fine particles constituting the aforementioned heat insulating material are characterized in that 50% or more of their volume are dispersed with a mode of particle size between 0.1 μm and 1.0 μm. Insulated windows.

2. In claim 1, The aforementioned mechanism is a mechanism that can move the liquid in contact with the insulating material in order to move the insulating material. Insulated windows.

3. Claim 2 is characterized in that the heat insulating material is hydrophobic and the liquid mainly consists of water. Insulated windows.

4. In claim 2, The mechanism comprises an elastic cavity capable of accommodating the thermal insulation material and the liquid on the lower side of the space, and a compression mechanism that can increase or decrease the volume of the elastic cavity. The mechanism moves the thermal insulation material from the elastic cavity to the space by reducing the volume of the elastic cavity using the compression mechanism, and moves the thermal insulation material from the space to the elastic cavity by increasing the volume of the elastic cavity using the compression mechanism. Insulated windows.

5. In claim 2, The mechanism comprises an upper elastic cavity capable of housing the thermal insulation material above the space, a lower elastic cavity capable of housing the liquid below the space, and a compression mechanism capable of increasing or decreasing the volume of the lower elastic cavity. The aforementioned mechanism is By reducing the volume of the lower elastic cavity using the compression mechanism, the liquid is moved from the lower elastic cavity to the space, and the insulating material is moved from the space to the upper elastic cavity. The compression mechanism increases the volume of the lower elastic cavity, thereby moving the liquid from the space into the lower elastic cavity and moving the insulating material from the upper elastic cavity into the space. Insulated windows.

6. The device comprises a cavity whose shape can be changed, and an insulating material housed in the cavity, wherein the insulating material is in powder form and moves within the cavity in accordance with the change in shape. The aforementioned thermal insulation material is made from an aerogel having a three-dimensional network structure in which a framework is formed of secondary particles, which are aggregates of primary particles, and includes fine particles having a three-dimensional network structure in which a framework is formed of primary particles generated when the secondary particles are broken down. Thermal insulation material.

7. In claim 6, The aforementioned thermal insulation material is fluid and has volume-retaining properties that maintain its volume before and after the change in the shape of the cavity. Thermal insulation material.

8. In claim 6, The inside of the cavity is reduced to a pressure lower than the outside air pressure. Thermal insulation material.

9. In claim 6, The cavity is filled with a gas that has a lower thermal conductivity than air. Thermal insulation material.

10. In claim 6, The cavity further contains a liquid that is exclusive to the insulating material. Thermal insulation material.

11. In claim 6, the thermal insulation material is hydrophobic, The cavity is further filled with water. Thermal insulation material.

12. In claim 6, The cavity has one or more pairs of panels and an insulation material storage section. Each of the pair or more of the panels has a gap on the inside that can accommodate the insulation material. The insulation material storage section houses the insulation material, and as the volume of the space continuous with the gap changes, the insulation material is pushed into the gap of the panel or retrieved from the gap of the panel. Thermal insulation material.

13. In claim 10, The cavity comprises one or more pairs of panels, an insulation material storage section, and a liquid storage section. Each of the pair or more of the panels has a gap on the inside that can accommodate the insulation material. The insulation material storage section has a space continuous with the gap, and the insulation material can be stored in the space. The liquid storage section contains the liquid, and the liquid moves as the volume of the space continuous with the gap changes, pushing the insulating material into the gap of the panel or recovering it from the gap of the panel. Thermal insulation material.

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