Heat storage unit

Abstract

The present invention addresses the problem of providing a heat storage unit capable of sufficiently exhibiting a temperature control function by filling every nook and cranny of the gaps in an inorganic fibrous body with a heat storage body.　To solve the problem, the present invention comprises: an inorganic fibrous body formed by binding or contacting a plurality of inorganic fibers; a heat storage body in contact with the inorganic fibrous body; and a housing body for housing the inorganic fibrous body and the heat storage body, wherein the housing body has a three-dimensional shape, the housing body has a first plate portion and a second plate portion that have a first interval therebetween and extend while facing each other, and the plurality of inorganic fibers include inorganic fibers having a fiber length longer than the first interval.

Description

Heat storage unit

[0001] This invention relates to a heat storage unit.

[0002] A heat storage unit using inorganic fibers and a heat storage material is known.

[0003] International release 2020 / 218216 International release 2023 / 189974

[0004] Conventional heat storage units have struggled to fill every void in the inorganic fiber structure with heat storage material. In other words, it was difficult to supply 100% of the heat storage material relative to the porosity of the inorganic fiber structure. As a result, these heat storage units were unable to perform adequate temperature control functions.

[0005] The present invention has been made in view of the above-mentioned points. Its purpose is to provide a heat storage unit that can fully perform its temperature control function by filling every corner of the gaps between inorganic fibers with a heat storage material.

[0006] The heat storage unit according to the present invention is characterized by comprising: an inorganic fibrous body formed by bonding or contacting a plurality of inorganic fibers; and a housing for housing the inorganic fibrous body, wherein the housing has a three-dimensional shape, and the housing has a first plate portion and a second plate portion that have a first interval and extend opposite to each other, and the plurality of inorganic fibers include inorganic fibers having a fiber length longer than the first interval.

[0007] The heat storage material fills every nook and cranny of the gaps between the inorganic fibers, allowing the temperature control function to be fully utilized.

[0008] This is a perspective view showing the external appearance of the heat storage unit 10 according to this embodiment. A plan view (A) shows the first top plate portion 110a of the heat storage unit 10, and a bottom view (B) shows the second top plate portion 110b. A cross-sectional view (A) shows the orientation of the inorganic fibers 310 within the storage portion 150, the average fiber length FL of the inorganic fibers 310, and the average fiber diameter FD of the inorganic fibers 310, and a cross-sectional view (B) shows the state of the inorganic fiber body 300 within the storage portion 150. A photograph (A) shows the surface condition of a portion of the inorganic fiber body 300 on the upper surface in a plan view, a photograph (B) shows the surface condition of a portion of the inorganic fiber body 300 on the side surface in a side view, and a photograph (C) shows the cross-section indicated by arrow A-A in Figure 1. A table shows the configuration and evaluation results of the heat storage units for each embodiment and comparative example.

[0009] In this specification, when upper and lower limits are specified as numerical specifications for a certain configuration, all numerical ranges are substantially disclosed, including numerical ranges using only any upper limit, numerical ranges using only any lower limit, and numerical ranges combining any upper and lower limit.

[0010] <<<<<Summary of this embodiment>>>> <<First feature>> According to the first feature, a heat storage unit is provided, comprising: an inorganic fiber body formed by bonding or contacting a plurality of inorganic fibers; a housing for housing the inorganic fiber body, wherein the housing has a three-dimensional shape, and the housing has a first plate portion and a second plate portion that have a first interval between them and extend toward each other, and the plurality of inorganic fibers include inorganic fibers having a fiber length longer than the first interval.

[0011] The heat storage unit comprises an inorganic fiber body and a container. The inorganic fiber body is formed by binding or contacting multiple inorganic fibers. The binding or contact of the inorganic fibers allows heat to be transferred throughout the entire inorganic fiber body.

[0012] The containment body houses inorganic fibers. The containment body can stabilize the state of the inorganic fibers. The containment body can also house a heat storage material. When a heat storage material is housed in the containment body, the heat storage material comes into contact with the inorganic fibers within the containment body. Heat can be transferred from the inorganic fibers to the heat storage material, and heat can be transferred from the heat storage material to the inorganic fibers. By housing the heat storage material in the containment body, it can function as a heat storage unit. In other words, when a heat storage material is housed in the containment body, it can be called a heat storage unit, and when the heat storage material is not housed in the containment body (the state before the heat storage material is housed in the containment body), it can be called a heat storage material housing unit, a heat storage material housing unit, or a component for a heat storage unit.

[0013] Furthermore, the container has a three-dimensional shape and can hold a desired amount of inorganic fiber.

[0014] The containment has a first plate portion and a second plate portion that extend opposite each other and have a first spacing between them. The spacing between the first plate portion and the second plate portion becomes the first spacing. An inorganic fiber is held between the first plate portion and the second plate portion. When a heat storage body is contained in the containment, the inorganic fiber and the heat storage body are held between the first plate portion and the second plate portion.

[0015] Multiple inorganic fibers include inorganic fibers having a fiber length longer than the first interval. By making the fiber length longer than the first interval, the inorganic fibers can be made to come into contact with each other more easily. By supporting and repelling each other through contact, the inorganic fibers can be made to form gaps between adjacent inorganic fibers more easily. In other words, by making the inorganic fibers longer, when a heat storage body is housed in a container, space can be secured to hold the heat storage body, and the amount of heat storage body supplied to the gaps can be increased.

[0016] <<Second Feature>> The second feature is that, in the first feature, the device further comprises a heat storage material in contact with the inorganic fiber. Any heat storage material having desired thermal properties can be used.

[0017] <<Third Feature>> The third feature is that, in the first feature, the container has a flattened shape.

[0018] By forming the container into a flat shape, inorganic fibers having a fiber length longer than the first interval can be used based on the first interval. This makes it easy to form voids between adjacent inorganic fibers, thereby securing a space for holding the heat storage body.

[0019] <<Fourth characteristic>> The fourth characteristic is that, in the first characteristic, among two points located on the contour of the first plate portion and positioned on the contour on the first extension surface where the first plate portion extends, a second interval between the two points that are farthest apart from each other is longer than the first interval; and among two points located on the contour of the second plate portion and positioned on the contour on the second extension surface where the second plate portion extends, a third interval between the two points that are farthest apart from each other is longer than the first interval.

[0020] Based on the first interval, the second interval, and the third interval, inorganic fibers having a fiber length that is longer than the first interval and shorter than the second interval and the third interval can be used. This makes it easy to form voids between adjacent inorganic fibers, thereby securing a space for holding the heat storage body.

[0021] Note that when the first plate portion and the second plate portion have the same shape and size, the second interval and the third interval have the same length. For example, when the container has a shape such as a rectangular parallelepiped or a cylinder, the second interval and the third interval are the same.

[0022] In contrast, when the first plate portion and the second plate portion have different shapes and sizes, the second interval and the third interval have different lengths. For example, when the container has a shape of a frustum such as a quadrangular frustum or a circular frustum, the second interval and the third interval have different lengths. Even in this case, the first interval is shorter than the second interval and the third interval, and the fiber length of the inorganic fibers is longer than the first interval and shorter than the second interval and the third interval.

[0023] <<Fifth Feature>> The fifth feature is that, in the first feature, the pressure loss of the inorganic fiber measured by the following measurement method is 0.040 MPa or less, or 0.035 MPa or less. The lower limit of the pressure loss is not particularly limited, but for example, it is 0.001 MPa or 0.010 MPa. (Measurement Method) Prepare an inorganic fiber with a planar width of 100 mm, a depth of 100 mm, and a thickness of 3 mm. Prepare two pipes (flow channels) with an inner diameter of 4.5 mm. Sandwich the inorganic fiber between the front and back (thickness direction) of the inorganic fiber with the pipes so that the openings of each pipe are in the same position, and set up so that air is supplied from the front pipe and air is discharged from the rear pipe. Place a pressure gauge in each pipe. Then, measure the flow rate of the air using a flow meter installed in the front pipe and adjust the flow rate so that the flow rate of the supplied air is 100 L / min. After 10 seconds, when the flow rate has been adjusted to 100 L / min, the pressure is read from the two pressure gauges placed in each pipe, and the pressure loss is calculated using the following equation 1. Ａ (MPa)-P Ｂ (MPa) = pressure loss (MPa) (Equation 1) P Ａ : Air pressure in the piping supplying air P Ｂ : Air pressure in the piping that discharges air

[0024] By setting the pressure loss of the inorganic fiber to this range, the heat storage material can be easily densely packed within the inorganic fiber, making it easier to form a heat storage unit with excellent heat storage capabilities.

[0025] <<Sixth Feature>> The sixth feature is that, in the first feature, the aspect ratio, which is the ratio of the average fiber length of the plurality of inorganic fibers to the average fiber diameter of the plurality of inorganic fibers (average fiber length / average fiber diameter), is between 20 and 200. The aspect ratio may be 30 or more, 40 or more, or 50 or more, and may also be 150 or less, 120 or less, or 100 or less.

[0026] By setting the aspect ratio within this range, it is easier to form an inorganic fiber 300 with desired physical properties and to create a heat storage unit with excellent heat storage capabilities.

[0027] As used herein, the average fiber diameter is calculated as the average of the fiber diameters of 20 fibers, where the fiber diameter is calculated as the equivalent circle diameter from the cross-sectional area of metal fibers in an arbitrary vertical cross-section of inorganic fibers using known software. The average fiber length is calculated as the average value obtained by measuring the fiber lengths of 20 inorganic fibers.

[0028] <<Seventh Characteristic>> The seventh characteristic is, according to the second characteristic, that where VA represents the apparent volume of the inorganic fiber body in the container, VB represents the true volume of the inorganic fiber body in the container, and VC represents the volume of the heat storage body in the container, the filling rate of the heat storage body represented by [VC / (VA-VB)] is 75.0% by volume or more. The heat storage body filling rate may be 80.0% by volume or more, 85.0% by volume or more, or 87.0% by volume or more. The upper limit of the heat storage body filling rate is, for example, 98.0% by volume, 95.0% by volume, or 92.0% by volume. The apparent volume of the inorganic fiber body in the container is calculated as the "volume of the outer dimensions of the inorganic fiber body" including the inorganic fibers and the voids between the inorganic fibers by measuring the outer dimensions of the fiber body in the container, and the true volume of the inorganic fiber body in the container is calculated from the apparent volume of the inorganic fiber body and the density (or specific gravity) of the inorganic fibers (inorganic fiber body).

[0029] More specifically, the heat storage body filling rate is calculated as follows. The heat storage body filling rate is calculated as "[heat storage body filling amount (g)] / [(ideal) heat storage body filling amount (g) calculated from the space factor of inorganic fibers] × 100". [Heat storage body filling amount (g)] is calculated as "[weight of the housing after filling the heat storage body (g)] - [weight of the housing before filling the heat storage body (g)]". [(Ideal) heat storage body filling amount (g) calculated from the space factor of inorganic fibers] is "( [volume of the internal space of the container (cm ３ )] - [true volume of the inorganic fiber body (cm ３ )]) × [heat storage body density (g / cm ３ )]". [True volume of the inorganic fiber body (cm ３ )] is calculated as "[apparent volume of the inorganic fiber body (calculated from outer dimension measurement) (cm ３ )] × [space factor of the inorganic fiber body (%)] / 100".

[0030] In other words, the heat storage material filling rate is calculated as shown in the following formula (1): Heat storage material filling rate = (MB - MA) / ((VD - VB) × ρ) × 100 (1) MA = weight of the enclosure before filling with heat storage material (g) MB = weight of the enclosure after filling with heat storage material (g) VB = true volume of inorganic fiber (cm³) ３ ) VD = Volume of the internal space of the containment (cm³) ３ ρ = density of the heat storage material (g / cm³) ３ )

[0031] By setting the heat storage material filling rate within this range, it is considered that the heat storage material is adequately filled within the heat storage unit, making it easier to form a heat storage unit with excellent heat storage capabilities.

[0032] The true volume of an inorganic fiber refers to the volume of the inorganic fiber excluding the void portion (the volume occupied only by the solid portion of the inorganic fiber).

[0033] <<Feature 8>> The eighth feature is that, in the first feature, when the apparent volume of the inorganic fiber in the container is VA and the true volume of the inorganic fiber in the container is VB, the fiber occupancy rate, expressed as [VB / VA], is 10 to 60 volume%. The fiber occupancy rate may be 15 volume% or more, or it may be 50 volume% or less, 45 volume% or less, 40 volume% or less, 35 volume% or less, 30 volume% or less, or 25 volume% or less. The fiber occupancy rate indicates the proportion of inorganic fiber in the space occupied by the inorganic fiber. Note that when the inorganic fiber is contained so as to be in close contact with the inner wall of the container, the apparent volume of the inorganic fiber in the container and the volume of the internal space of the container are approximately the same. The fiber occupancy rate is calculated by measuring the volume of the external dimensions of the inorganic fiber (the volume calculated from the measurement of the external dimensions of the inorganic fiber, including the inorganic fibers and the voids between the inorganic fibers), and using the mass of the inorganic fiber and the density of the inorganic fibers based on the following formula. Fiber occupancy rate (%) = (Mass of inorganic fiber / (Volume of the external dimensions of the inorganic fiber × Density of inorganic fibers)) × 100

[0034] By setting the fiber space factor within this range, it is easier to form a heat storage unit that has sufficient void space for filling with heat storage material while also exhibiting the thermal conductivity and other properties derived from inorganic fibers.

[0035] <<Ninth Feature>> The ninth feature is that, in the first feature, it further comprises a tube for forming a cooling channel through which the heat transfer medium can flow. The heat transfer medium is used at a temperature lower than the melting point of the heat storage body, and the temperature of the heat transfer medium is not particularly limited. For example, a temperature difference of 1 to 20°C, and even 5 to 15°C or 5 to 10°C may be used.

[0036] By increasing the contact area between the heat storage element and the cooling channel, heat can be exchanged more efficiently with the refrigerant.

[0037] <<<<<Details of this embodiment>>>>> The embodiment will be described below with reference to the drawings.

[0038] <<Definition of Direction, etc.>> <Horizontal Direction> The horizontal direction is the direction that intersects the Earth's gravity at a right angle.

[0039] <Vertical Direction> The vertical direction refers to the direction of gravity. It is the direction indicated by the string from which an object is suspended. It refers to the direction perpendicular to the horizontal direction.

[0040] <Downward> This refers to the direction of gravity.

[0041] <Upward> This refers to the direction opposite to the direction of gravity.

[0042] <Upstream direction / Forward direction> This refers to the direction in which the flow of a heat transfer medium, such as a refrigerant or heating medium, moves upstream.

[0043] <Downstream direction / Backward direction> This refers to the direction downstream of the flow of a heat transfer medium such as a refrigerant or heating medium.

[0044] <Rightward direction> This refers to the direction of moving to the right when going upstream or forward.

[0045] <Left direction> This refers to the direction of moving to the left when facing upstream or forward.

[0046] <<<Specific Structure of Heat Storage Unit 10>>> Figure 1 is a perspective view showing the external appearance of the heat storage unit 10 according to this embodiment. Figure 2(A) is a plan view showing the first top plate portion 110a of the heat storage unit 10, and Figure 2(B) is a bottom view showing the second top plate portion 110b. The heat storage unit 10 includes a housing 100, a heat storage body 200, an inorganic fiber body 300, and a tubular body 400.

[0047] <<Housing 100>> The housing 100 is composed of a first top plate portion 110a and a second top plate portion 110b, a first side plate portion 120a and a second side plate portion 120b, a front portion 130a and a rear portion 130b. The housing 100 forms the enclosure.

[0048] The outline of the housing 100 is defined by the first top plate portion 110a and the second top plate portion 110b, the first side plate portion 120a and the second side plate portion 120b, the front portion 130a and the rear portion 130b. The space surrounded by the first top plate portion 110a and the second top plate portion 110b, the first side plate portion 120a and the second side plate portion 120b, the front portion 130a and the rear portion 130b becomes the housing portion 150 of the housing 100.

[0049] <First top plate portion 110a and second top plate portion 110b> The housing 100 has a first top plate portion 110a and a second top plate portion 110b facing each other. The first top plate portion 110a and the second top plate portion 110b have a flat, rectangular shape. The first top plate portion 110a and the second top plate portion 110b are positioned apart from each other in the vertical direction.

[0050] <First side plate portion 120a and second side plate portion 120b> The housing 100 has a first side plate portion 120a and a second side plate portion 120b facing each other. The first side plate portion 120a and the second side plate portion 120b have a flat, rectangular shape. The first side plate portion 120a and the second side plate portion 120b are positioned spaced apart from each other in the left-right direction.

[0051] <Front section 130a and rear section 130b> The housing 100 has a front section 130a and a rear section 130b that face each other. The front section 130a and the rear section 130b have a flat, rectangular shape. The front section 130a and the rear section 130b are positioned apart from each other in the front-rear direction.

[0052] <Housing section 150> The housing 100 has a rectangular parallelepiped shape, formed by a first top plate portion 110a and a second top plate portion 110b, a first side plate portion 120a and a second side plate portion 120b, a front portion 130a and a rear portion 130b. The housing 100, which is the casing, is formed by the first top plate portion 110a and the second top plate portion 110b, the first side plate portion 120a and the second side plate portion 120b, the front portion 130a and the rear portion 130b.

[0053] The inner surface of the housing 100 defines the housing section 150, which is the housing space of the housing 100. The housing section 150 is a space surrounded by the inner surfaces of the first top plate 110a and the second top plate 110b, the inner surfaces of the first side plate 120a and the second side plate 120b, and the inner surfaces of the front section 130a and the rear section 130b. In this embodiment, the housing section 150 has a rectangular parallelepiped shape. The materials of the first top plate 110a and the second top plate 110b, the first side plate 120a and the second side plate 120b, and the front section 130a and the rear section 130b can be copper, stainless steel, or the like.

[0054] <Assembly of the container 100> For example, the container 100 can be constructed by using the first top plate portion 110a as the lid portion, and the second top plate portion 110b, the first side plate portion 120a and the second side plate portion 120b, the front portion 130a and the rear portion 130b as the dish portion, and attaching the first top plate portion 110a to the dish portion. The choice between the lid portion and the dish portion is arbitrary. It is sufficient that the container 100 can be sealed.

[0055] <First spacing DT1, spacing HL1, spacing HL2, volume of storage section 150> The spacing between the inner surface of the first top plate 110a and the inner surface of the second top plate 110b is the first spacing DT1. The first spacing DT1 indicates the vertical height of the storage section 150. The spacing between the inner surface of the first side plate 120a and the inner surface of the second side plate 120b is the spacing HL2. Spacing HL2 indicates the left-right width of the storage section 150. The spacing between the inner surface of the front part 130a and the inner surface of the back part 130b is the spacing HL1. Spacing HL1 indicates the front-rear width of the storage section 150. The first spacing DT1 is shorter than spacing HL1 and spacing HL2. That is, the first spacing DT1 < spacing HL1 and the first spacing DT1 < spacing HL2 are true. As a result, the containment body 100 has a flattened shape.

[0056] <Volume of the housing section 150, apparent volume VA of the inorganic fiber, true volume VB of the inorganic fiber 300 in the housing 100, volume VC of the heat storage body 200 in the housing> When the inorganic fiber 300 is housed in close contact with the inner wall of the housing 100, the apparent volume VA of the inorganic fiber in the housing 100 and the volume of the internal space of the housing 100 are approximately the same. In other words, the volume of the housing section 150 determined by the first spacing DT1, spacing HL1, and spacing HL2 is the same as the apparent volume VA of the inorganic fiber in the housing 100. The heat storage body 200 and the inorganic fiber 300, which will be described later, are housed in the housing section 150. The volume (true volume) occupied by the inorganic fiber 300 housed in the housing 100 (housing section 150) is referred to as VB. The volume occupied by the heat storage body 200 housed in the housing 100 (housing section 150) is referred to as VC.

[0057] <Second spacing DT2, third spacing DT3> Figure 2 is a plan view (A) showing the first top plate portion 110a of the heat storage unit 10 and a bottom view (B) showing the second top plate portion 110b.

[0058] The length of the diagonal of the first top plate portion 110a is the distance between the two points that are furthest apart from each other, among two points located on the contour of the first top plate portion 110a, on the contour of the first extending surface to which the first top plate portion 110a extends. The length of the diagonal of the first top plate portion 110a is the second distance DT2.

[0059] The length of the diagonal of the second top plate portion 110b is the distance between the two points located on the contour of the second top plate portion 110b that are furthest apart from each other, among the two points located on the contour of the first extending surface on which the second top plate portion 110b extends. The length of the diagonal of the second top plate portion 110b is the third distance DT3.

[0060] The characteristic length to which the first top plate portion 110a and the second top plate portion 110b extend may be not only the length of the sides, such as the spacing HL1 and spacing HL2, but also the length of the diagonal. In this case as well, the first spacing DT1 is shorter than the second spacing DT2 and the third spacing DT3. The conditions DT1 < DT2 and DT1 < DT3 hold true. Even in this way, the container 100 has a flattened shape.

[0061] Furthermore, if the first top plate portion 110a and the second top plate portion 110b have the same shape and size, the second spacing DT2 and the third spacing DT3 will be the same length. For example, if the container 100 has a shape such as a rectangular parallelepiped or a cylinder, the second spacing DT2 and the third spacing DT3 will be the same.

[0062] In contrast, if the first top plate portion 110a and the second top plate portion 110b have different shapes and sizes, the second spacing DT2 and the third spacing DT3 will be of different lengths. For example, if the container 100 has the shape of a truncated pyramid, such as a truncated square pyramid or a truncated cone, the second spacing DT2 and the third spacing DT3 will be of different lengths. Even in this case, the first spacing DT1 is shorter than the second spacing DT2 and the third spacing DT3, and the fiber length of the inorganic fiber is longer than the first spacing DT1 and shorter than the second spacing DT2 and the third spacing DT3.

[0063] <<Tubes 400>> The heat storage unit 10 has a plurality of tubes 400. In the example shown in Figure 1, there are three tubes 400. The tubes 400 have a long cylindrical shape. The tubes 400 have long through holes 410 along their longitudinal direction. A heat transfer medium such as a refrigerant or a thermostat can flow through the through holes 410. The three tubes 400 are arranged to be in contact with the heat storage body 200 and inorganic fiber body 300 housed in the housing section 150. Heat exchange can occur between the heat transfer medium flowing through the through holes 410 and the heat storage body 200 and inorganic fiber body 300 in the housing section 150. The material, shape, and size of the tubes 400 should be appropriately determined to allow for efficient heat exchange with the heat storage body 200 and inorganic fiber body 300.

[0064] The front section 130a and the rear section 130b have three through holes. The three tubular bodies 400 are inserted through the through holes formed in the front section 130a and the rear section 130b. The three tubular bodies 400 are arranged in the front-rear direction. The three tubular bodies 400 have straight, curved, or bent shapes within the housing section 150. The shape and arrangement of the three tubular bodies 400 within the housing section 150 can be appropriately determined according to the amount of heat storage material 200 and inorganic fiber material 300, and the heat exchange between the heat storage material 200 and the tubular bodies.

[0065] <<Heat Storage Body 200>> The heat storage body 200 according to the present invention transfers heat from a heat transfer medium through an inorganic fiber body 300, and stores and releases heat. The heat storage body 200 can be of a sensible heat storage type, a latent heat storage type, or a chemical heat storage type, and is not particularly limited.

[0066] The sensible heat storage system 200 has a relatively low heat storage density and therefore low heat storage efficiency, but it is excellent in terms of stability, safety, cost, ease of handling, and durability. The latent heat storage system 200 has a high heat storage density and excellent heat storage efficiency, as well as excellent stability, safety, cost, ease of handling, and durability. The chemical heat storage system 200 has a very high heat storage density and very excellent heat storage efficiency, but it has low stability, safety, cost, ease of handling, and durability. Therefore, the latent heat storage system 200 can be preferably used in the heat storage unit according to the present invention. Furthermore, the heat storage temperature and heat storage energy can be controlled by adjusting the components of the heat storage system and the mixing ratio.

[0067] A preferred example of a latent heat storage type heat storage body 200 is one that stores the heat applied to the heat storage body 200 as latent heat when a solid-liquid phase transition occurs, or one that stores the heat as latent heat when a solid-solid phase transition occurs.

[0068] Examples of heat storage bodies 200 that utilize the latent heat of solid-liquid phase transitions include single-component heat storage bodies such as water (ice), paraffin-based materials, alkali metal hydroxides, magnesium hydroxide, beryllium hydroxide, alkaline earth metal hydroxides, inorganic salts such as nitrates, and inorganic hydrated salts such as sodium acetate trihydrate; and mixtures of multiple components such as mixtures of inorganic salts or inorganic hydrates such as a mixture of magnesium nitrate hexahydrate and magnesium chloride hexahydrate, mixtures of organic compounds such as a mixture of lauric acid and capric acid, and mixtures of inorganic salts and organic compounds such as a mixture of ammonium nitrate and urea. Furthermore, for paraffin-based materials, for example, n-pentadecane, an n-paraffin-based heat storage body, or a material consisting of elastomer and paraffin can be used.

[0069] The heat storage body 200, which utilizes the latent heat of solid-liquid phase transition, can be used in the heat storage unit of the present invention by, for example, applying heat to the heat storage body 200 that utilizes the latent heat of solid-liquid phase transition to make it liquid, and then impregnating it with the inorganic fiber body 300 according to the present invention, or by immersing the inorganic fiber body 300 in the heat storage body 200 in the liquid phase, then lowering the temperature to make it solid, and then embedding the inorganic fiber body 300 in the heat storage body 200.

[0070] The heat storage body 200, which utilizes the latent heat of solid-solid phase transition, can be an organic compound such as a polyethylene glycol copolymer crosslinked conjugate; LiMnO ４ LiVS ２ LiVO ２ NaNiO ２ LiRh ２ O ４ , V ２ O ３ , V ４ O ７ , V ６ O １１ Ti ４ O ７ SmBaFe ２ O ５ , EuBaFe ２ O ５ , GdBaFe ２ O ５ , TbBaFe ２ O ５ DyBaFe ２ O ５ HoBaFe ２ O ５ YBaFe ２ O ５ ,PrBaCo ２ O ５．５ DyBaCo ２ O ５．５４ HoBaCo ２ O ５．４８ YBaCo ２ O ５．４９ Transition metal ceramics such as niobium (Nb), molybdenum (Mo), ruthenium (Ru), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os), iridium (Ir), etc., in which vanadium is partially substituted with other metals such as vanadium dioxide (VO2). ２ ), can be given as examples. As vanadium dioxide obtained by substituting a portion of vanadium with the aforementioned metal, if the substituted metal is M and the amount of substituted M is x, then V １－ｘ M ｘ O ２ This is a compound that can be expressed as follows: where x is a decimal greater than 0 and less than 1.

[0071] The heat storage body 200, which utilizes the latent heat of a solid-solid phase transition, can be used in the heat storage unit of the present invention by, for example, pulverizing the heat storage body 200 that utilizes the latent heat of a solid-solid phase transition and filling or supporting it in the inorganic fiber body 300 according to the present invention, or by embedding the inorganic fiber body 300 in the pulverized heat storage body 200.

[0072] Furthermore, the heat storage body 200, which utilizes the latent heat of the solid-to-solid phase transition, can be used as a sheet, block, or other lumpy material by laminating it with or bringing it into contact with the inorganic fiber body 300.

[0073] <<Inorganic Fiber 300>> <Shape of Inorganic Fiber 300> The inorganic fiber 300 may have, for example, a long strip or a sheet shape. The inorganic fiber 300 only needs to be such that it can be housed in the storage section 150 to constitute the heat storage unit 10.

[0074] <Material of Inorganic Fiber 300> The inorganic fiber 300 is not particularly limited as long as it does not hinder the effects of the present invention, but examples include a sheet made by wet-processing inorganic fibers 310, an inorganic fiber sheet made by a known dry-process nonwoven fabric manufacturing method, and a sheet woven with inorganic filament fibers (e.g., mesh). Of these, the wet-process fiber sheet is preferable because it is possible to make the sheet thinner, and furthermore, the inorganic fibers 310 etc. are uniformly dispersed to form a dense mesh structure, resulting in a uniform sheet with little variation in thickness and weight. By making the inorganic fiber 300 thin and uniform, it is possible to include multiple inorganic fiber 300 in the heat storage unit, and the heat storage unit as a whole can be made to have uniform and rapid heat exchange for heat storage and heat dissipation. From another viewpoint, the inorganic fiber sheet made by a dry-process nonwoven fabric manufacturing method is preferable because it is easy to adjust the physical properties of the inorganic fiber sheet, including the fiber density.

[0075] The fibers used in the inorganic fiber body 300 are not particularly limited as long as they are inorganic fibers. Inorganic fibers may be metallic fibers or non-metallic fibers. Examples of inorganic fibers include single metallic fibers such as copper, silver, gold, platinum, aluminum, nickel, chromium, and tungsten; alloy fibers such as stainless steel, copper alloys, tungsten alloys, and chromium alloys; glass fibers; alumina fibers; carbon fibers; silica fibers; and boron fibers. These fibers can be used individually or in combination. Of these, materials with high thermal conductivity are preferred in order to increase the rate of heat storage and heat dissipation of the heat storage unit, metals are preferred, and copper, silver, aluminum, stainless steel, and copper alloys are more preferred.

[0076] Furthermore, the inorganic fiber 300 may contain organic fibers, as long as they do not hinder the effects of the present invention. The content of organic fibers can be, for example, 20% by mass or less, 10% by mass or less, 5% by mass or less, or 1% by mass or less, based on the total amount of the inorganic fiber 300.

[0077] Furthermore, the heat storage unit 10 can also use an organic fiber sheet instead of the inorganic fiber body 300. In particular, when using an organic fiber sheet made of a material with higher thermal conductivity than the heat storage body 200 described later, it is possible to realize the effects of the heat storage unit of the present invention. Examples of organic fiber sheets made of materials with high thermal conductivity include crystalline polymer fibers such as aramid fibers, polyethylene fibers, polyamide fibers, polytetrafluoroethylene fibers, and polyethylene terephthalate fibers. However, the fiber sheet used in the present invention is preferably made of a material with high thermal conductivity, and if an organic fiber sheet with low thermal conductivity is used instead of an inorganic fiber sheet, the performance of the heat storage unit will be inferior.

[0078] Other additives may be added to the inorganic fiber 300 as needed. Examples of additives include binders and thickeners. Examples of binders include acrylic resin and polyvinyl alcohol.

[0079] The inorganic fiber body 300 can be made by bonding inorganic fibers 310 with a binder resin during manufacturing, but it is preferable that the sheet be a sintered inorganic fiber sheet, which is sintered in a vacuum or non-oxidizing atmosphere at a temperature in which the inorganic fibers 310 do not completely melt. Thus, the inorganic fiber body 300 may have a structure in which the fibers are bonded together using a binder resin or the like, or a structure in which the inorganic fibers are fused together by sintering. Furthermore, by using a sintered inorganic fiber sheet made of 100% inorganic fibers, it is possible to produce a strong sheet in which the inorganic fibers 310 are fused together without containing any organic matter. When there are many bonding or fusion points between the inorganic fibers 310, heat transfer within the inorganic fibers 310 occurs rapidly, making it possible to efficiently store and release heat in the heat storage unit.

[0080] Figure 3(A) is a cross-sectional view showing the orientation of the inorganic fibers 310 within the housing 150, the average fiber length FL, and the average fiber diameter FD of the inorganic fibers 310. Figure 3(B) is a cross-sectional view showing the state of the inorganic fiber body 300 within the housing 150. The inorganic fiber body 300 is composed of a plurality of inorganic fibers 310. The fiber diameter and fiber length of the plurality of inorganic fibers 310 constituting the inorganic fiber body 300 are not constant but are distributed in various ways. That is, the plurality of inorganic fibers 310 constituting the inorganic fiber body 300 have fiber diameters and fiber lengths of various lengths. The fiber diameter and fiber length of the inorganic fibers 310 are typically characterized by the average fiber diameter FD and the average fiber length FL. In this specification, unless otherwise specified, fiber diameter means average fiber diameter FD, and fiber length means average fiber length FL. Furthermore, by changing the fiber diameter, fiber length, fiber density, material, etc., of the inorganic fiber, the pressure loss, heat storage capacity, fiber occupancy rate, etc., of the inorganic fiber can be adjusted.

[0081] <Average Fiber Diameter FD> The average fiber diameter FD of the fibers used in the inorganic fiber 300 is not particularly limited, but is preferably, for example, greater than 50 μm, 60 μm or more, or 70 μm or more. The upper limit of the fiber diameter is, for example, 300 μm, 200 μm, or 150 μm.

[0082] <Average Fiber Length FL> The average fiber length FL of the fibers used in the inorganic fiber 300 is not particularly limited as long as it does not hinder manufacturing, but it is preferably greater than 500 μm, 1000 μm or more, 2000 μm or more, 2500 μm or more, 3000 μm or more, or 4000 μm or more. The upper limit of the fiber length is, for example, 50 mm, 30 mm, 20 mm, 15 mm, 10 mm, or 8000 μm.

[0083] <Aspect Ratio> The ratio of the average fiber length FL to the average fiber diameter FD is called the aspect ratio. The aspect ratio is preferably 20 or more, and preferably 200 or less.

[0084] <Orientation of Inorganic Fibers 310> By increasing the aspect ratio, the length of each inorganic fiber 310 can be increased. By making the inorganic fibers 310 longer, it becomes easier for the inorganic fibers 310 to come into contact with each other. By supporting each other through contact and repelling each other, it becomes easier to form gaps between adjacent inorganic fibers 310. In other words, by making the inorganic fibers 310 longer, space can be secured to hold the heat storage body 200.

[0085] Furthermore, by making the inorganic fibers 310 longer, the amount of inorganic fibers 310 can be secured. This allows for the maintenance of the heat transfer characteristics of the heat storage unit 10 using the inorganic fibers 310 while securing space to hold the heat storage body 200.

[0086] Furthermore, the inorganic fibers 310 support each other, making them less likely to fall over horizontally. Multiple inorganic fibers 310 are arranged at various angles θ with respect to the first top plate portion 110a and the second top plate portion 110b. The angle θ is preferably between 0 degrees and 45 degrees. Having multiple inorganic fibers 310 at various angles θ makes it easier for them to come into contact with the pipe body 400, thereby increasing the efficiency of heat transfer between the pipe body 400 and the heat storage body 200.

[0087] <Relationship between average fiber length FL and size of container 100> As shown in Figure 1, the size of the container is characterized by the first interval DT1, interval HL1, and interval HL2. Furthermore, as shown in Figure 2, the size of the container is also characterized by the second interval DT2 and the third interval DT3.

[0088] The average fiber length FL of the inorganic fibers 310 constituting the inorganic fiber body 300 is longer than the first interval DT1. Also, the average fiber length FL is shorter than intervals HL1, HL2, the second interval DT2, and the third interval DT3.

[0089] Thus, the typical average fiber length FL of the inorganic fibers 310 constituting the inorganic fiber body 300 can be characterized by comparing it with the size of the container.

[0090] Figure 4(A) is a photograph showing the surface condition of a portion of the inorganic fiber 300 on the upper surface in a plan view. Figure 4(B) is a photograph showing the surface condition of a portion of the inorganic fiber 300 on the side surface in a side view. Figure 4(C) is a photograph showing the section indicated by arrow A-A in Figure 1.

[0091] As can be seen from Figures 4(A) to 4(C), the average fiber length FL of the inorganic fibers 310 constituting the inorganic fiber body 300 is longer than the first interval DT1 and shorter than intervals HL1, HL2, the second interval DT2, and the third interval DT3.

[0092] <<Formation of Heat Storage Unit 10>> <Preparation of Inorganic Fiber Body 300> Multiple inorganic fibers 310 to constitute the inorganic fiber body 300 are placed on a support base (not shown). Heat is applied to the multiple inorganic fibers 310 to connect (bond) the inorganic fibers 310 to each other and form an integrated inorganic fiber body 300. By connecting the inorganic fibers 310 to each other, heat can be easily transferred to the entire integrated inorganic fiber body 300.

[0093] The length, width, and thickness of the integrated inorganic fiber body 300 can be adjusted by changing the quantity and arrangement of the multiple inorganic fibers 310. The quantity and arrangement of the multiple inorganic fibers 310 should be determined according to the desired shape and size of the inorganic fiber body 300, and then heat should be applied.

[0094] Depending on the desired characteristics of the heat storage unit 10, the inorganic fibers 310 may not be connected to each other, but rather the inorganic fibers 310 may be entangled or simply in contact with each other.

[0095] <Assembly of the heat storage unit 10> The heat storage unit 10 can be assembled by placing the inorganic fiber material 300 in the housing section 150 and filling it with the heat storage material 200.

[0096] First, three tubular bodies 400 are placed inside the housing section 150, extending from the front section 130a and the rear section 130b. One of the first top plate section 110a and the second top plate section 110b, the first side plate section 120a and the second side plate section 120b, or the front section 130a and the rear section 130b is used as a lid to house the inorganic fiber material 300 in the housing section 150. The inorganic fiber material 300 is stacked and stored in the housing section 150 to the extent that the entire housing section 150 is filled.

[0097] Alternatively, the three tubular bodies 400 may be arranged after the inorganic fiber 300 has been placed in the housing section 150.

[0098] The lid is brazed with Ni or a similar material to seal the entire container 100. Depending on the material of the container 100, the sintering temperature, whether or not brazing is performed, and the brazing material should be determined as appropriate.

[0099] After sealing the container 100, the heat storage element 200 is injected into the container section 150 through an injection hole (not shown) in the container 100. The air inside the container 100 is discharged through an exhaust hole (not shown) in the container 100. Discharging the air from the container 100 promotes the injection of the heat storage element 200, allowing the heat storage element 200 to fill the entire container section 150.

[0100] After injecting the heat storage body 200, the injection and discharge holes are sealed with a metal such as copper or stainless steel. In this way, the housing portion 150 of the heat storage unit 10 is filled with inorganic fiber 300 and heat storage body 200, and the inorganic fiber 300 is in contact with the entire housing portion 100. Heat can be accurately exchanged between the housing 160 and the inorganic fiber 300. This makes it easier to transfer heat from the heat transfer medium outside the heat storage unit 10 to the heat storage body 200 via the inorganic fiber 300, and also makes it easier to transfer heat stored in the heat storage body 200 to the heat transfer medium outside the heat storage unit 10 via the inorganic fiber 300.

[0101] In the example described above, multiple inorganic fiber sheets 300 were stacked to fill the storage section 150. However, if the thickness of a single inorganic fiber sheet 300 is approximately the same as the depth of the storage section 150, a single inorganic fiber sheet 300 can be used without stacking multiple inorganic fiber sheets 300. Furthermore, if the inorganic fiber sheet 300 is thin, the storage section 150 can be filled by stacking the inorganic fiber sheets 300 in an appropriate combination.

[0102] <<<<<Scope of Embodiments>>>>> As described above, this embodiment has been presented. However, the descriptions and drawings that constitute part of this disclosure should not be understood as limiting. Various embodiments not described herein are included.

[0103] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following.

[0104] <<Manufacturing of the Thermal Storage Unit>> A thermal storage unit with a simplified structure was manufactured for evaluation purposes as follows.

[0105] <Example 1> Copper fibers with an average fiber diameter of 90 μm and an average fiber length of 6000 μm were used as the inorganic fibers. An inorganic fiber sheet was prepared from the inorganic fibers by dry papermaking. The inorganic fiber sheet was sintered at 1,020°C for 40 minutes in an atmosphere of 75% hydrogen gas and 25% nitrogen gas to produce a sintered inorganic fiber sheet. The prepared sintered inorganic fiber sheet was sealed in the internal space of a rectangular parallelepiped container as shown in Figure 1. In order to easily carry out the evaluation test described later, an acrylic container with only the top plate made of copper was used as the container. The sintered inorganic fiber sheet was pre-integrated into the copper top plate, the sintered inorganic fiber sheet was placed inside the acrylic container with the opening closed by the top plate. Heptadecane was prepared as a heat storage body. The heat storage body was introduced into the acrylic container and left to stand in a refrigerator (approximately 10°C) for a sufficient amount of time to solidify, and this was used as a heat storage unit for evaluation. In addition, the heat storage unit according to Example 1 was made without tubing for simplification. The heat storage unit according to Example 1 was manufactured as described above. The gap between the housings (corresponding to the first gap DT1 in Figure 1) is 3000 μm.

[0106] Figure 5 shows the fiber space ratio and heat storage material filling ratio of the obtained heat storage unit.

[0107] <Examples 2-5, Comparative Examples 1 and 2> Except for changing the average fiber diameter and average fiber length of the inorganic fibers used, and adjusting the density of the inorganic fiber body to obtain the fiber body fill ratio and heat storage body filling ratio shown in Figure 5, the heat storage units according to Examples 2-5 and Comparative Examples 1 and 2 were manufactured in the same manner as in Example 1.

[0108] Here, the pressure loss of the sintered inorganic fiber sheets used in the heat storage units of each example and comparative example was measured according to the measurement method described above. The measurement results are shown in Figure 5.

[0109] <<Evaluation>> For each heat storage unit, the temperature retention time was measured according to the following measurement method. The measurement results are shown in Figure 5.

[0110] (Method for measuring temperature retention time) Place the heat storage unit in an oven at 30°C. Measure the surface temperature of the copper plate (9 locations) on the top of the heat storage unit using a data logger. Calculate the time it takes for the average temperature of the 9 locations to equalize, and define this as the temperature retention time.

[0111] From the above results, it can be understood that, by setting an appropriate relationship between the fiber length of the inorganic fibers and the gap in the containment, the inorganic fibers inside the containment are easily oriented appropriately, and a heat storage unit with excellent temperature retention is constructed according to each embodiment.

[0112] It can be applied to applications that regulate temperature by transferring heat to a heat transfer medium such as a refrigerant or a thermostat. Cross-reference of related applications

[0113] This application claims priority over Japanese Patent Application No. 2025-055471, filed with the Japan Patent Office on 28 March 2025, all of which disclosures are incorporated herein by reference in their entirety.

Claims

1. A heat storage unit comprising: an inorganic fibrous body formed by bonding or contacting a plurality of inorganic fibers; and a housing for housing the inorganic fibrous body, wherein the housing has a three-dimensional shape, and the housing has a first plate portion and a second plate portion that have a first interval between them and extend opposite to each other, and the plurality of inorganic fibers include inorganic fibers having a fiber length longer than the first interval.

2. The heat storage unit according to claim 1, further comprising a heat storage body in contact with the inorganic fiber, wherein the housing houses the heat storage body together with the inorganic fiber.

3. The heat storage unit according to claim 1, wherein the housing has a flattened shape.

4. The heat storage unit according to claim 1, wherein the second distance between two points located on the contour of the first plate portion, which are the two points that are furthest apart from each other among the two points located on the contour of the first extending surface on which the first plate portion extends, is longer than the first distance, and the third distance between two points located on the contour of the second plate portion, which are the two points that are furthest apart from each other among the two points located on the contour of the second extending surface on which the second plate portion extends, is longer than the first distance.

5. The heat storage unit according to claim 1, wherein the pressure loss when air in the inorganic fiber material, measured by the measurement method described below, is measured at a flow rate of 100 L / min is 0.040 MPa or less. (Measurement method) Prepare an inorganic fiber material with a planar width of 100 mm, a depth of 100 mm, and a thickness of 3 mm. Prepare two pipes (flow channels) with an inner diameter of 4.5 mm. Sandwich the inorganic fiber material between the two pipes on the front and back (thickness direction) so that the openings of each pipe coincide, and set up so that air is supplied from the front pipe and discharged from the rear pipe. Place a pressure gauge in each pipe. Then, measure the air flow rate using a flow meter installed in the front pipe and adjust the flow rate so that the supplied air flow rate is 100 L / min. Ten seconds after the flow rate has been adjusted to 100 L / min, read the pressure from the two pressure gauges placed in each pipe and calculate the pressure loss from the following formula 1. P Ａ (MPa)-P Ｂ (MPa) = pressure loss (MPa) (Equation 1) P Ａ : Air pressure in the piping supplying air P Ｂ : Air pressure in the piping that discharges air 6. The heat storage unit according to claim 1, wherein the aspect ratio, which is the ratio of the average fiber length of the plurality of inorganic fibers to the average fiber diameter of the plurality of inorganic fibers (average fiber length / average fiber diameter), is 20 to 200.

7. The heat storage unit according to claim 2, wherein when the apparent volume of the inorganic fiber in the container is VA, the true volume of the inorganic fiber in the container is VB, and the volume of the heat storage material in the container is VC, the heat storage material filling rate, expressed as [VC / (VA-VB)], is 75.0 volume% or more.

8. The heat storage unit according to claim 1, wherein when the apparent volume of the inorganic fiber in the containment is VA and the true volume of the inorganic fiber in the containment is VB, the fiber occupancy ratio, expressed as [VB / VA], is 10 to 60 volume%.

9. The heat storage unit according to claim 1, further comprising a tubular body for forming a cooling channel through which a heat transfer medium can flow.

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