JP2022001771A - Heat insulation structure and manufacturing method of heat insulation structure - Google Patents

Abstract

To provide a heat insulation structure which can improve heat insulation performance while suppressing an increase of a thickness, and can suppress a rise of a surface temperature of a vacuum heat insulation material.SOLUTION: A heat insulation structure 100 comprises: a vacuum heat insulation material 130 having a core material and an outer cover material for covering the core material while vacuuming and sealing it; a first foaming heat insulation material 110 which is arranged while tightly adhering to the vacuum heat insulation material 130 at one side face, and in which a recess 111 is formed at one side face; and a second foaming heat insulation material 120 which is arranged while covering the vacuum heat insulation material 130 and the first foaming heat insulation material 110. An air heat insulation layer 101 formed of air which is sealed in the recess 111 is formed at the first foaming heat insulation material 110. The air heat insulation layer 101 is arranged at a high-temperature heat source side rather than the vacuum heat insulation material 130.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a heat insulating structure and a method for manufacturing a structural heat insulating body.

A hot water storage type equipped with a molded heat insulating material that covers the hot water storage tank from the outside and a plate-shaped vacuum heat insulating material that is embedded inside the molded heat insulating material and has an inner surface facing the hot water storage tank and an outer surface facing the outside. The heat insulating structure of the water heater is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-217505

However, in the heat insulating structure as shown in Patent Document 1, in order to improve the heat insulating performance, it is inevitable that the thickness of the heat insulating structure increases in the heat transfer direction. When, for example, an aluminum vapor-deposited film, which is less affected by the heat bridge, is used as the exterior material of the vacuum heat insulating material of the heat insulating structure, if the surface temperature of the vacuum heat insulating material rises, the aluminum vapor-filmed film deteriorates. Therefore, the thickness of the heat insulating structure is increased in order to suppress the increase in the surface temperature of the vacuum heat insulating material of the heat insulating structure.

This disclosure is made to solve such a problem. The purpose is to provide a heat insulating structure and a method for manufacturing a heat insulating structure capable of improving the heat insulating performance while suppressing an increase in thickness in the heat transfer direction and suppressing a rise in the surface temperature of the vacuum heat insulating material of the heat insulating structure. To do.

The heat insulating structure according to the present disclosure has a vacuum heat insulating material having a core material and an outer cover material that vacuum-seals and covers the core material, and one side surface of the vacuum heat insulating material is arranged in close contact with the vacuum heat insulating material. A first foam heat insulating material having a recess formed therein, a vacuum heat insulating material and a second foam heat insulating material provided over the vacuum heat insulating material and the first foam heat insulating material are provided, and the first foam heat insulating material includes the inside of the recess. An air heat insulating layer is formed by the air trapped in the vacuum heat insulating material, and the air heat insulating layer is arranged on the high temperature heat source side of the vacuum heat insulating material.

Further, the method for manufacturing a heat insulating structure according to the present disclosure is a first foam heat insulating material in which a recess is formed on one side surface of a vacuum heat insulating material having a core material and an outer cover material that vacuum-seals and covers the core material. The vacuum heat insulating material and the first foamed heat insulating material are brought into close contact with each other so that the surface on which the recess is formed is on the side of the vacuum heat insulating material. It is covered with a material and integrally molded, and an air heat insulating layer is formed by the air trapped in the recess in the first foam heat insulating material.

According to the heat insulating structure and the method for manufacturing the heat insulating structure according to the present disclosure, the heat insulating performance is improved while suppressing the increase in the thickness in the heat transfer direction, and the surface temperature of the vacuum heat insulating material of the heat insulating structure rises. It has the effect of being able to suppress it.

It is sectional drawing which shows the structure of the hot water storage tank provided with the heat insulating structure which concerns on Embodiment 1. FIG. It is a perspective view which shows typically the structure of the heat insulating structure which concerns on Embodiment 1. FIG. It is sectional drawing which shows typically the structure of the heat insulating structure which concerns on Embodiment 1. FIG. It is sectional drawing which shows typically the structure of the recess of the 1st foam insulation material provided in the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows an example of the temperature distribution of the hot water storage tank which is a high temperature heat source which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the heat transfer amount at the time of changing the air insulation pitch of the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the surface temperature of a vacuum heat insulating material when the air insulation pitch of the insulation structure which concerns on Embodiment 1 is changed. It is a figure explaining the surface temperature of the vacuum heat insulating material of the heat insulating structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation pitch of the insulation structure which concerns on Embodiment 1 and the bending amount of the 1st foam insulation material. It is a figure which shows typically the shape of the concave part and the convex part of the 1st foam insulation material provided in the heat insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth of the insulation structure which concerns on Embodiment 1 and the lower limit value of the air insulation pitch. It is a figure which shows the relationship between the air insulation depth and the heat transfer amount at the time of changing the air insulation pitch of the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the surface temperature of a vacuum heat insulating material when the air insulation pitch of the insulation structure which concerns on Embodiment 1 is changed. It is a figure explaining the combination of the air insulation depth and the air insulation pitch of the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the heat transfer amount at the time of changing the air insulation pitch of the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the surface temperature of a vacuum heat insulating material when the air insulation pitch of the insulation structure which concerns on Embodiment 1 is changed. It is a figure explaining the combination of the air insulation depth and the air insulation pitch of the insulation structure which concerns on Embodiment 1. FIG. It is a figure which shows an example of the specifications of the aluminum vapor deposition film and the aluminum foil film of the heat insulating structure which concerns on Embodiment 1. FIG. It is a perspective view which shows typically the structure of the modification of the heat insulating structure which concerns on Embodiment 1. FIG. It is a figure which shows typically the application example of the modification of the heat insulating structure which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between the air insulation depth and the heat transfer amount at the time of changing the air insulation pitch of the insulation structure which concerns on Embodiment 2. FIG. FIG. 21 is an enlarged view showing a main part of FIG. 21. It is a figure which shows the relationship between the air insulation depth and the surface temperature of a vacuum heat insulating material when the air insulation pitch of the insulation structure which concerns on Embodiment 2 is changed. It is a figure which shows the relationship between the air insulation pitch of the insulation structure which concerns on Embodiment 2 and the bending amount of the 1st foam insulation material. It is a figure explaining the combination of the air insulation depth and the air insulation pitch of the insulation structure which concerns on Embodiment 2. FIG. It is a figure which shows the relationship between the air insulation depth and the heat transfer amount at the time of changing the air insulation pitch of the insulation structure which concerns on Embodiment 2. FIG. It is a figure which shows the relationship between the air insulation depth and the surface temperature of a vacuum heat insulating material when the air insulation pitch of the insulation structure which concerns on Embodiment 2 is changed. It is a figure explaining the combination of the air insulation depth and the air insulation pitch of the insulation structure which concerns on Embodiment 2. FIG.

A form for carrying out the heat insulating structure and the method for manufacturing the structural heat insulating body according to the present disclosure will be described with reference to the attached drawings. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be appropriately simplified or omitted. In the following description, for convenience, the positional relationship of each structure may be expressed with reference to the illustrated state. It should be noted that the present disclosure is not limited to the following embodiments, and is free combination of each embodiment, modification of any component of each embodiment, or each of them, as long as the purpose of the present disclosure is not deviated. It is possible to omit any component of the embodiment.

Embodiment 1.
The first embodiment of the present disclosure will be described with reference to FIGS. 1 to 20. FIG. 1 is a cross-sectional view showing the configuration of a hot water storage tank provided with a heat insulating structure. FIG. 2 is a perspective view schematically showing the configuration of the heat insulating structure. FIG. 3 is a cross-sectional view schematically showing the structure of the heat insulating structure. FIG. 4 is a cross-sectional view schematically showing the structure of the recess of the first foamed heat insulating material included in the heat insulating structure. FIG. 5 is a diagram showing an example of the temperature distribution of the hot water storage tank which is a high temperature heat source. FIG. 6 is a diagram showing the relationship between the air insulation depth and the heat transfer amount when the air insulation pitch of the insulation structure is changed. FIG. 7 is a diagram showing the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material when the air heat insulating pitch of the heat insulating structure is changed. FIG. 8 is a diagram illustrating the surface temperature of the vacuum heat insulating material of the heat insulating structure. FIG. 9 is a diagram showing the relationship between the air insulation pitch of the heat insulating structure and the amount of bending of the first foamed heat insulating material. FIG. 10 is a diagram schematically showing the shapes of the concave portions and convex portions of the first foamed heat insulating material included in the heat insulating structure. FIG. 11 shows the relationship between the air heat insulating depth of the heat insulating structure and the lower limit of the air heat insulating pitch. It is a figure. FIG. 12 is a diagram showing the relationship between the air insulation depth and the amount of heat transfer when the air insulation pitch of the insulation structure is changed. FIG. 13 is a diagram showing the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material when the air heat insulating pitch of the heat insulating structure is changed. FIG. 14 is a diagram illustrating a combination of the air insulation depth and the air insulation pitch of the insulation structure. FIG. 15 is a diagram showing the relationship between the air insulation depth and the amount of heat transfer when the air insulation pitch of the insulation structure is changed. FIG. 16 is a diagram showing the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material when the air heat insulating pitch of the heat insulating structure is changed. FIG. 17 is a diagram illustrating a combination of the air insulation depth and the air insulation pitch of the insulation structure. FIG. 18 is a diagram showing an example of specifications of an aluminum-deposited film and an aluminum foil film of a heat insulating structure. FIG. 19 is a perspective view schematically showing the configuration of a modified example of the heat insulating structure. FIG. 20 is a diagram schematically showing an application example of a modified example of the heat insulating structure.

FIG. 1 shows a configuration example in which the heat insulating structure 100 according to this embodiment is provided in the hot water storage tank 1. Inside the hot water storage tank 1, for example, high-temperature hot water heated by an electric hot water supply device is stored. In the illustrated configuration example, the hot water storage tank 1 has a dome shape whose upper end portion is convex upward, a dome shape whose lower end portion is convex downward, and a cylindrical outer shape in the central portion. The hot water storage tank 1 is made of, for example, stainless steel (SUS).

The periphery of the hot water storage tank 1 is covered with a heat insulating material. Here, the heat insulating structure 100 of this embodiment is provided on the side surface portion of the hot water storage tank 1. Foaming heat insulating materials 10 are provided on the upper surface portion and the lower surface portion of the hot water storage tank 1. An outer shell portion 20 is provided on the outer side of the heat insulating structure 100 and the foamed heat insulating material 10. The outer shell portion 20 is made of a metal such as iron or aluminum.

Next, the configuration of the heat insulating structure 100 according to this embodiment will be described with reference to FIG. 2. The heat insulating structure 100 of this embodiment includes a first foam heat insulating material 110, a second foam heat insulating material 120, and a vacuum heat insulating material 130. The vacuum heat insulating material 130 has a core material and an outer cover material. The core material is, for example, a laminated structure of glass wool or a fiber sheet. The outer cover material is vacuum-sealed with the core material.

One side of the first foam heat insulating material 110 is arranged in close contact with the vacuum heat insulating material 130. A recess 111 is formed on one side surface of the first foam heat insulating material 110, that is, a surface in close contact with the vacuum heat insulating material 130. In the illustrated configuration example, a plurality of recesses 111 are formed. A convex portion 112 is formed so as to project relatively between the plurality of concave portions 111.

The second foam heat insulating material 120 is provided so as to cover the vacuum heat insulating material 130 and the first foam heat insulating material 110. The first foam heat insulating material 110 and the vacuum heat insulating material 130 are configured so as to be completely covered with the second foam heat insulating material 120 so as not to come into contact with the outside air.

The first foam heat insulating material 110 is arranged on the high temperature heat source side with respect to the vacuum heat insulating material 130. That is, in the configuration example described here, the first foam heat insulating material 110 is arranged closer to the hot water storage tank 1 than the vacuum heat insulating material 130.

As described above, the surface of the first foam heat insulating material 110 on which the recess 111 is formed is in close contact with the vacuum heat insulating material 130. Therefore, each recess 111 of the first foam heat insulating material 110 is surrounded by the first foam heat insulating material 110 and the vacuum heat insulating material 130 and sealed. Air is confined in each of the sealed recesses 111 to form an air heat insulating portion. Then, the air heat insulating layer 101 is formed in the first foamed heat insulating material 110 as an aggregate of the air heat insulating portions formed in the respective recesses 111. As described above, the first foam heat insulating material 110 is arranged on the high temperature heat source side with respect to the vacuum heat insulating material 130. Therefore, the air heat insulating layer 101 is arranged on the high temperature heat source side with respect to the vacuum heat insulating material 130.

Next, a method for manufacturing the heat insulating structure 100 of this embodiment, which is configured as described above, will be described. First, the first foam heat insulating material 110 having the recess 111 formed on one side surface is brought into close contact with the vacuum heat insulating material 130 so that the one side surface, that is, the surface on which the recess 111 is formed is on the side of the vacuum heat insulating material 130. Let me. Next, the vacuum heat insulating material 130 and the first foamed heat insulating material 110 are covered with a second foamed heat insulating material different from the first foamed heat insulating material 110 and integrally molded. At this time, when the second foamed heat insulating material 120 is foamed, the vacuum heat insulating material 130 and the first foamed heat insulating material 110 that are brought into close contact with each other are inserted into the inside of the second foamed heat insulating material 120 and molded to integrally foam the heat insulating material. The structure is 100. As a result, the air heat insulating layer 101 is formed in the first foamed heat insulating material 110 by the air trapped in the recess 111.

The material of the second foam insulation material 120 is, for example, a two-component miscible urethane foam. Further, in this embodiment, the material of the first foamed heat insulating material 110 is also the same two-component miscible urethane foam as the second foamed heat insulating material 120.

Next, the evaluation of the heat insulating property of the heat insulating structure 100 configured as described above will be described with reference to specific examples. FIG. 3 shows various dimensional parameters used for evaluating the heat insulating property of the heat insulating structure 100. Here, the "air insulation pitch" is a dimension between the centers of the convex portions 112 sandwiching one concave portion 111, as shown in FIG. Further, the "air insulation block dimension" is the width of one convex portion 112, as also shown in FIG. That is, the air insulation block dimension is the thickness of the foam insulation between the respective air insulation portions.

As shown in FIG. 3, in the heat transfer direction, the hot water, the wall portion of the hot water storage tank 1, the second foam heat insulating material 120, the first foam heat insulating material 110 including the air heat insulating layer 101, the vacuum heat insulating material 130, and the second foam heat insulating material. The material 120, the outer shell portion 20, and the outside air are arranged in this order. The thickness of the wall portion of the hot water storage tank 1 is 0.5 mm. The thickness of the second foamed heat insulating material 120 is 4 mm for each of the hot water (high temperature heat source side) side and the outside air (low temperature heat source side). The thickness of the outer shell portion 20 is 0.5 mm. Further, the dimension of the air insulation block is 5 mm. Under the initial conditions as a reference, the thickness of the first foam insulation material 110 including the air insulation layer 101 is 8 mm, the thickness of the air insulation layer 101 (also referred to as the air insulation depth) is 4 mm, and the air insulation pitch is 5 mm. do. The thickness of the foam insulation material (air insulation block) between the air insulation layers is constant (5 mm).

FIG. 5 shows an example of the temperature distribution of the internal water temperature of the hot water storage tank 1, which is an example of a high-temperature heat source. In the hot water storage tank 1, high-temperature water is distributed in the upper part and low-temperature water is distributed in the lower part, and the high-temperature water region is divided into several temperature zones. The hot water storage temperature when the water is full is about 65 ° C. on the high temperature side and about 40 ° C. on the low temperature side. However, at the time of boiling, the water temperature in the hot water storage tank 1 rises to around 90 ° C. Therefore, in the evaluation of the heat insulating structure 100 used for the hot water storage tank 1, it is necessary to consider the maximum temperature of the high temperature heat source at 90 ° C. Therefore, from now on, when the maximum temperature of the high-temperature heat source is 90 ° C. and the minimum temperature is 40 ° C., the air insulation pitch in the vertical direction is set to a maximum of 180 mm, and the temperature distribution is given at equal intervals.

FIG. 6 shows the relationship between the air insulation depth and the amount of heat transfer when the air insulation pitch is changed in the above model. The horizontal axis of FIG. 6 is the air insulation depth dimension (mm), and the vertical axis is the heat transfer amount (W). From the figure, it can be seen that when the depth dimension of the air insulation layer 101 is 6 mm or less, the larger the air insulation pitch, the greater the amount of heat transfer suppression. However, the difference is about 0.08% at the maximum, and it can be said that there is almost no difference. On the other hand, it can be seen that the amount of heat transfer tends to increase as the air insulation pitch increases with the boundary of 6 mm. From this, when the material of the first foamed heat insulating material 110 including the air heat insulating layer 101 is the same urethane foam as the second foamed heat insulating material 120, the air heat insulating layer 101 has a thickness of 6 mm as a boundary. It is suggested that the effect of convection within 101 is significant.

FIG. 7 shows the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material 130 when the air heat insulating pitch is changed in the above model. The horizontal axis of FIG. 7 is the air heat insulating depth dimension (mm), and the vertical axis is the surface temperature (° C.) of the vacuum heat insulating material 130. As can be seen from the figure, in the region where the air insulation depth is small, the surface temperature of the vacuum heat insulating material 130 tends to decrease as the air insulation pitch increases. Further, when the air heat insulating depth is between 10 mm and 20 mm, the surface temperature difference of the vacuum heat insulating material 130 when the air heat insulating pitch is changed is not large. In the region where the air insulation depth is 20 mm or more, the temperature is the lowest at the air insulation pitch of 15 mm.

Here, the heat resistant temperature of the surface film of the vacuum heat insulating material 130 is set to 100 ° C. ± 10 to 12%. Of the total number of surface films produced, the probability of occurrence of defects (exceeding the heat resistant temperature) is 1 × E-05, and the safety factor is calculated to be 1.212. Assuming a normal distribution as the surface temperature distribution of the surface film of the vacuum heat insulating material 130, as shown in FIG. 8, the surface temperature of the vacuum heat insulating material 130 to be targeted at the safety factor 1.212 is 82.49 ° C. .. As shown in FIG. 7, it can be seen that the surface temperature of the vacuum heat insulating material 130 is the target temperature of 82.49 ° C. or lower at any air heat insulating depth and air heat insulating pitch.

In the heat insulating structure 100 of this embodiment, in order to integrally foam the first foamed heat insulating material 110 and the second foamed heat insulating material 120, the first foamed heat insulating material 110 including the air heat insulating layer 101 has a second foamed material. The pressure (300 g / cm ^ 2) at the time of foaming the heat insulating material 120 is applied evenly. Therefore, the first foam heat insulating material 110 bends so that the bottom portion of the recess 111 approaches the vacuum heat insulating material 130 side. FIG. 9 shows the relationship between the air insulation pitch (mm) and the amount of deflection (mm) of the first foam insulation material 110. The amount of bending of the first foamed heat insulating material 110 is shown by a distance at which the bottom portion of the recess 111 approaches the vacuum heat insulating material 130 side from the state where no external force acts on the first foamed heat insulating material 110. The amount of deflection y of the first foamed heat insulating material 110 at the air heat insulating pitch x can be expressed by the following approximate formula (1).

y = 1.373E-067x ^ 4-2.735E-05x ^ 3 + 1.996E-04x ^ 2-5.551E-04x + 1.431E-05 ... (1)

When the amount of bending of the first foam heat insulating material 110 reaches the air heat insulating depth, the bottom portion of the recess 111 comes into contact with the vacuum heat insulating material 130 and the air heat insulating portion disappears. From the figure, it can be seen that when the air insulation depth is 6 mm, the air insulation pitch is limited to about 50 to 51 mm. Further, it can be seen that when the air insulation depth is 4 mm (initial value), the air insulation pitch is limited to about 46 mm.

Next, the lower limit of the air insulation pitch with respect to the air insulation depth will be described. In FIG. 6, when the air insulation depth is larger than 6 mm, the heat transfer amount becomes smaller as the air insulation pitch becomes smaller, but the mold used for molding the concave portion 111 and the convex portion 112 of the first foam insulation material 110 Considering the strength and the filling state of the molding material in the tip portion of the convex portion 112 at the time of molding, there is a lower limit value for the practical air insulation pitch. Here, as shown in FIG. 10, the draft in the mold used when molding the concave portion 111 and the convex portion 112 of the first foamed heat insulating material 110 is 5 °, and the tip portion of the mold for molding the concave portion 111 is formed. The minimum dimension is 5 mm, and the minimum dimension of the tip of the convex portion 112 is 5 mm.

FIG. 11 shows the relationship between the air insulation depth and the lower limit of the air insulation pitch that satisfy the conditions shown in FIG. The relationship between the limit value y of the air insulation pitch and the air insulation depth x is expressed by the following approximate equation (2).

y = 0.350x + 10.000 ... (2)

From the figure, it can be seen that, for example, the minimum value of the air insulation depth for ensuring the minimum dimension of 5 mm at the tip of the mold is 4 mm, and the air insulation pitch at that time is 11.4 mm. In the case of the set of the air insulation depth and the air insulation pitch in the region above the line shown in FIG. 11, the first foam insulation material 110 in which the concave portion 111 and the convex portion 112 are formed is formed without affecting the manufacturing yield. It can be produced.

12 and 13, respectively, show the case where the air insulation layer 101 is not provided in FIGS. 6 and 7, respectively, for comparison. As can be seen from these figures, when the air heat insulating depth exceeds 8.5 mm, the amount of heat transfer increases when the air heat insulating layer 101 is provided as compared with the case where the air heat insulating layer 101 is not provided. , The surface temperature of the vacuum heat insulating material 130 also becomes high. Therefore, when the first foamed heat insulating material 110 and the second foamed heat insulating material 120 are made of the same quality urethane foam, the thickness of the air heat insulating layer 101 is preferably 8.5 mm or less.

Based on the above, with reference to FIG. 14, the combination of the air insulation depth and the air insulation pitch that can be adopted in the insulation structure 100 of this embodiment will be described. First, as described above, the thickness of the air insulation layer 101, that is, the upper limit of the air insulation depth is set to 8.5 mm. The upper limit of the air insulation pitch in a certain air insulation depth is determined by the amount of bending of the first foam insulation material 110. Further, the lower limit of the air insulation pitch in a certain air insulation depth is determined by the practical limit of the mold used for molding the first foam insulation material 110. Therefore, the combination of the air insulation depth and the air insulation pitch that can be adopted is within the regions of the A portion and the B portion hatched in FIG. Within the regions of the A portion and the B portion, it is possible to achieve both the heat insulating performance and the productivity of the heat insulating structure 100.

Here, the portion B is a region where the depth of air insulation is 6 mm to 8.5 mm, and the smaller the air insulation pitch, the smaller the amount of heat transfer. Therefore, in the B portion, it is advantageous for the heat insulating performance to bring the air heat insulating pitch closer to the lower limit.

On the other hand, the part A is a region where the depth of air insulation is 4 mm to 6 mm, and the larger the air insulation pitch, the smaller the amount of heat transfer. Therefore, in the A part, it is advantageous for the heat insulating performance to bring the air heat insulating pitch closer to the upper limit. Further, in this region, the larger the air insulation depth, the smaller the amount of heat transfer. Therefore, by making the air insulation depth as large as possible, that is, close to 6 mm, and making the air insulation pitch close to 51 mm, which is the upper limit when the air insulation depth is 6 mm, the heat insulation performance is improved and the foam insulation material is used. It is possible to reduce the manufacturing cost by reducing the amount used.

15 and 16, respectively, show the case where the vertical width in the temperature distribution model of the high temperature heat source is expanded to 720 mm and the air insulation pitch is from 240 mm to 720 mm, respectively, in FIGS. 12 and 13, respectively. It is a thing. As can be seen from these figures, even if the air insulation pitch is increased to 240 mm or more, no significant change in the insulation performance is observed as compared with the case where the air insulation pitch is 180 mm or less. From this, it is presumed that the influence of heat transfer due to convection in the air insulation layer 101 when the air insulation pitch is expanded has already reached saturation. However, especially when the air insulation depth is small, a slight change in the amount of heat transfer can be seen by expanding the air insulation pitch to 240 mm or more, and the difference is about 0.6% at the maximum.

As can be seen from FIG. 15, when the vertical width of the high-temperature heat source is expanded to 720 mm and the air insulation depth exceeds 6 mm, the case where the air insulation layer 101 is provided as compared with the case where the air insulation layer 101 is not provided. The amount of heat transfer is larger in the case of. Further, as can be seen from FIG. 16, when the vertical width of the high temperature heat source is expanded to 720 mm and the air heat insulating depth exceeds 8 mm, the air heat insulating layer 101 is provided as compared with the case where the air heat insulating layer 101 is not provided. In this case, the surface temperature of the vacuum heat insulating material 130 becomes higher. Therefore, when the vertical width of the high-temperature heat source is large, the thickness of the air heat insulating layer 101 is preferably 6 mm or less.

Based on the above, with reference to FIG. 17, the combination of the air insulation depth and the air insulation pitch that can be adopted when the vertical width of the high temperature heat source is large in the insulation structure 100 of this embodiment will be described. First, as described above, the thickness of the air insulation layer 101, that is, the upper limit of the air insulation depth is 6 mm. Therefore, the combination of the air insulation depth and the air insulation pitch that can be adopted in this case is within the region of the part A hatched in FIG. Within the region of the A portion, it is possible to achieve both the heat insulating performance and the productivity of the heat insulating structure 100.

To summarize the above, when the material of the first foam insulation material 110 is urethane foam, it is desirable that the air insulation pitch is at least 55 mm and the air insulation depth is 8.5 mm or less. Further, especially when the high temperature heat source is large, it is more desirable that the air insulation pitch is 51 mm or less and the air insulation depth is 6 mm or less.

In the heat insulating structure 100 configured as described above, by forming the air heat insulating layer 101 on the high temperature heat source side of the vacuum heat insulating material 130, the heat insulating performance is improved while suppressing the increase in thickness in the heat transfer direction. As a result, it is possible to suppress an increase in the surface temperature of the vacuum heat insulating material 130.

Next, an example of an advantage by suppressing the increase in the surface temperature of the vacuum heat insulating material 130 will be described. Generally, the surface of the vacuum heat insulating material 130 is filmed by the exterior material. Examples of the exterior material for forming the vacuum heat insulating material 130 include an aluminum foil film and an aluminum vapor-deposited film (FIG. 18). FIG. 18 shows an example of the specifications of (a) an aluminum-deposited film and (b) an aluminum foil film. As shown in the figure, the difference in the thickness of the entire exterior material of the aluminum foil film and the aluminum vapor-deposited film is about 6 microns, and the aluminum foil film is thinner. On the other hand, the total thermal conductivity λ is 19.88 W / mK for the aluminum foil film, while it is 0.42 W / mK for the aluminum-deposited film, which is a big difference. Is excellent.

In the heat insulating structure 100 according to this embodiment, the exterior material of the vacuum heat insulating material 130 can be changed from the aluminum foil film to the aluminum vapor-deposited film by suppressing the increase in the surface temperature of the vacuum heat insulating material 130. By changing the film of the vacuum heat insulating material 130 from foil to thin film deposition, the influence of the heat bridge is reduced, and the heat insulating ineffective area area can be reduced to about 1/3 to 1/5. Therefore, the deterioration of the heat insulating performance of the vacuum heat insulating material 130 can be suppressed.

As a modification of the heat insulating structure 100 according to this embodiment, as shown in FIG. 19, the first foamed heat insulating material 110 forming the air heat insulating layer 101 is configured to be composed of a plurality of foamed heat insulating material blocks 113. You may do it. An example of the foam insulation block 113 is schematically shown. The first foamed heat insulating material 110 as shown in FIG. 19A is obtained by integrally foaming with the second foamed heat insulating material 120 in a state where these foamed heat insulating material blocks 113 are bonded. That is, in the method of manufacturing the heat insulating structure 100 in this modification, the foamed heat insulating material block 113, which is a plurality of heat insulating material parts, is combined to form the first foamed heat insulating material 110. By doing so, for example, as shown in FIG. 20, when the temperature distribution of the high-temperature heat source is biased, it is possible to add an air insulation layer as much as necessary. Further, the pitch of the air heat insulating portion constituting the air heat insulating layer 101 can be easily changed according to the temperature distribution of the high temperature heat source. Further, in terms of productivity, it is possible to reduce the processing cost by reducing the mold size or the like.

The air insulating portions constituting the air insulating layer 101 may be arranged in a vertical and horizontal two-dimensional direction instead of being arranged in a vertical one-dimensional direction to form a grid. By doing so, it is possible to suppress the bending of the first foamed heat insulating material 110.

Further, in the above description, the case where the heat insulating structure 100 has a flat plate shape has been described as an example for easy understanding, but the shape of the heat insulating structure 100 may be curved or the like. The same effect can be obtained even if the heat insulating structure 100 is configured according to the outer shape of the high temperature heat source. Further, the target to which the heat insulating structure 100 is provided is not limited to the hot water storage tank 1, and may be, for example, a refrigerator or the like.

Embodiment 2.
The second embodiment of the present disclosure will be described with reference to FIGS. 21 to 28. FIG. 21 is a diagram showing the relationship between the air insulation depth and the heat transfer amount when the air insulation pitch of the insulation structure is changed. FIG. 22 is an enlarged view showing a main part of FIG. 21. FIG. 23 is a diagram showing the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material when the air heat insulating pitch of the heat insulating structure is changed. FIG. 24 is a diagram showing the relationship between the air insulation pitch of the heat insulating structure and the amount of bending of the first foamed heat insulating material. FIG. 25 is a diagram illustrating a combination of the air insulation depth and the air insulation pitch of the insulation structure. FIG. 26 is a diagram showing the relationship between the air insulation depth and the heat transfer amount when the air insulation pitch of the insulation structure is changed. FIG. 27 is a diagram showing the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material when the air heat insulating pitch of the heat insulating structure is changed. FIG. 28 is a diagram illustrating a combination of the air insulation depth and the air insulation pitch of the insulation structure.

In the second embodiment described here, in the configuration of the first embodiment described above, the first foamed heat insulating material including the air heat insulating layer is made of polystyrene foam. Hereinafter, the heat insulating structure according to the second embodiment will be described focusing on the differences from the first embodiment. The configuration in which the description is omitted is basically the same as that in the first embodiment. In the following description, the same or corresponding configurations as those in the first embodiment will be described with the same reference numerals as those used in the description of the first embodiment in principle.

The basic configuration and manufacturing method of the heat insulating structure 100 according to this embodiment are the same as those described as the first embodiment with reference to FIGS. 1 to 5. However, the material of the first expanded heat insulating material 110 of this embodiment is polystyrene foam (PS-FO), particularly bead method polystyrene foam (EPS).

FIG. 21 shows the relationship between the air insulation depth and the heat transfer amount when the air insulation pitch is changed in the insulation structure 100 of this embodiment. FIG. 22 is an enlarged view of a main part of FIG. 21. The horizontal axis of FIGS. 21 and 22 is the air insulation depth dimension (mm), and the vertical axis is the heat transfer amount (W). From these figures, it can be seen that when the depth dimension of the air insulation layer 101 is 10 mm or less, the larger the air insulation pitch, the greater the amount of heat transfer suppression. However, it can be said that there is almost no difference.

On the other hand, it can be seen that the amount of heat transfer tends to increase as the air insulation pitch increases with the boundary of 10 mm. From this, when the material of the first foamed heat insulating material 110 including the air heat insulating layer 101 is polystyrene foam, the influence of convection in the air heat insulating layer 101 is remarkable when the thickness of the air heat insulating layer 101 is 10 mm. It is suggested that it will appear.

Further, in FIG. 21, for comparison, the case where the first foamed heat insulating material 110 is made of bead method polystyrene foam and the air heat insulating layer 101 is not provided, and the case where the first foamed heat insulating material 110 is made of urethane foam and the air heat insulating layer 101 is provided. It also shows the case where it is not provided. When the first foamed heat insulating material 110 is compared with the same bead method polystyrene foam, when the air heat insulating depth exceeds about 15 mm to 15.5 mm, the air heat insulating layer 101 is provided as compared with the case where the air heat insulating layer 101 is not provided. In this case, the amount of heat transfer is larger. Therefore, when the first foamed heat insulating material 110 is made of beaded polystyrene foam, the air heat insulating depth, that is, the thickness of the air heat insulating layer 101 is preferably 15.5 mm or less.

On the other hand, as a reference, compared with the case where the first foamed heat insulating material 110 is made of urethane foam and the air heat insulating layer 101 is not provided, when the air heat insulating depth exceeds 6 mm, it is compared with the case where the air heat insulating layer 101 is not provided with urethane foam. Therefore, the amount of heat transfer is larger when the air insulating layer 101 is provided with polystyrene foam.

FIG. 23 shows the relationship between the air heat insulating depth and the surface temperature of the vacuum heat insulating material 130 when the air heat insulating pitch is changed in the heat insulating structure 100 of this embodiment. The horizontal axis of FIG. 23 is the air heat insulating depth dimension (mm), and the vertical axis is the surface temperature (° C.) of the vacuum heat insulating material 130. In the figure, as a comparison target, the case where the first foamed heat insulating material 110 is made of bead method polystyrene foam and the air heat insulating layer 101 is not provided, and the case where the first foamed heat insulating material 110 is made of urethane foam and the air heat insulating layer 101 is not provided. It also shows the case.

As can be seen from the figure, when the first foam heat insulating material 110 is compared with the same bead method polystyrene foam, if the air heat insulating depth is the following, the air heat insulating layer 101 is compared with the case where the air heat insulating layer 101 is not provided. The surface temperature of the vacuum heat insulating material 130 is lower when the vacuum heat insulating material 130 is provided. Further, as a reference, when the first foamed heat insulating material 110 is made of urethane foam and the air heat insulating layer 101 is not provided, if the air heat insulating depth is 5.5 mm or less, the air heat insulating layer 101 is not provided with urethane foam. In comparison with the above, the surface temperature of the vacuum heat insulating material 130 is lower when the air heat insulating layer 101 is provided with polystyrene foam.

FIG. 24 shows the relationship between the air insulation pitch (mm) and the amount of deflection (mm) of the first foam insulation material 110 in the insulation structure 100 of this embodiment. FIG. 24 corresponds to FIG. 9 described in the first embodiment. The amount of deflection y of the first foamed heat insulating material 110 at the air heat insulating pitch x can be expressed by the following approximate formula (3).

y = 2.959E-06x ^ 4-6.573E-05x ^ 3 + 6.616E-04x ^ 2-3.192E-03x + 7.085E-04 ... (3)

When the amount of bending of the first foam heat insulating material 110 reaches the air heat insulating depth, the bottom portion of the recess 111 comes into contact with the vacuum heat insulating material 130 and the air heat insulating portion disappears. From the figure, it can be seen that when the air insulation depth is 10 mm, the air insulation pitch is limited to about 47 to 48 mm. Further, it can be seen that when the air insulation depth is 4 mm (initial value), the air insulation pitch is limited to about 38 to 39 mm. Although it is out of the range shown in FIG. 24, when the air insulation depth is 15.5 mm, the air insulation pitch is limited to about 53 mm.

Based on the above, with reference to FIG. 25, the combination of the air insulation depth and the air insulation pitch that can be adopted in the insulation structure 100 of this embodiment will be described. First, as described above, the thickness of the air insulation layer 101, that is, the upper limit of the air insulation depth is 15.5 mm. The upper limit of the air insulation pitch in a certain air insulation depth is determined by the amount of bending of the first foam insulation material 110. Further, the lower limit of the air insulation pitch in a certain air insulation depth is determined by the practical limit of the mold used for molding the first foam insulation material 110. Therefore, the combination of the air insulation depth and the air insulation pitch that can be adopted is within the regions of the A portion, the B portion, and the C portion hatched in FIG. Within the regions of the A part, the B part and the C part, it is possible to achieve both the heat insulating performance and the productivity of the heat insulating structure 100.

Here, the C portion is a region where the air insulation depth is 10 mm to 15.5 mm, and the smaller the air insulation pitch, the smaller the amount of heat transfer. Therefore, in the C portion, it is advantageous for the heat insulating performance to bring the air heat insulating pitch closer to the lower limit. Further, the portion B has an air insulation depth of 5.5 mm to 10 mm, and the larger the air insulation pitch, the smaller the amount of heat transfer. Therefore, in the B portion, it is advantageous for the heat insulating performance to bring the air heat insulating pitch closer to the upper limit.

Similar to the B portion, the A portion also has an air insulation depth of 4 mm to 5.5 mm, and the larger the air insulation pitch, the smaller the amount of heat transfer. Further, the part A is a region where the amount of heat transfer is small as compared with the case where the first foam heat insulating material 110 is made of urethane foam and the air heat insulating layer 101 is not provided. Therefore, by setting the air insulation depth and the air insulation pitch of the part A, the amount of heat transfer is suppressed even when the first foam insulation material 110 is urethane foam or compared with the conventional insulation structure having no air insulation layer 101. It is possible to reduce the amount of energy consumed.

Further, if the air insulation depth can be secured to 5.5 mm or more, the first foam insulation material 110 is made of polystyrene foam and there is no air insulation layer 101 by setting the air insulation depth of the B portion and the C portion and the air insulation pitch. Compared with the case, the amount of heat transfer can be suppressed. Therefore, it can be effectively used for adjusting the balance between heat insulation performance and economy.

26 and 27 show, in FIGS. 21 and 23, the case where the vertical width of the temperature distribution model of the high-temperature heat source is expanded to 720 mm and the air insulation pitch is 240 mm or more, respectively. be. As can be seen from these figures, even if the air insulation pitch is increased to 240 mm or more, no significant change in the insulation performance is observed as compared with the case where the air insulation pitch is 180 mm or less. From this, it is presumed that the influence of heat transfer due to convection in the air insulation layer 101 when the air insulation pitch is expanded has already reached saturation. However, especially when the air insulation depth is small, a slight change in the amount of heat transfer can be seen by expanding the air insulation pitch to 240 mm or more, and the difference is about 0.7% at the maximum.

As can be seen from FIG. 26, when the vertical width of the high-temperature heat source is expanded to 720 mm and the air insulation depth is 11 mm or less, the air insulation layer 101 is provided as compared with the case where the air insulation layer 101 is not provided. In the case, the amount of heat transfer is smaller. Further, as can be seen from FIG. 27, when the vertical width of the high temperature heat source is expanded to 720 mm and the air heat insulating depth is 14 mm or less, the air heat insulating layer 101 is provided as compared with the case where the air heat insulating layer 101 is not provided. The surface temperature of the vacuum heat insulating material 130 is lower when the vacuum heat insulating material 130 is provided. Therefore, when the vertical width of the high-temperature heat source is large, the thickness of the air heat insulating layer 101 is preferably 11 mm or less.

Based on the above, with reference to FIG. 28, the combination of the air insulation depth and the air insulation pitch that can be adopted when the vertical width of the high temperature heat source is large in the insulation structure 100 of this embodiment will be described. First, as described above, the thickness of the air insulation layer 101, that is, the upper limit of the air insulation depth is 11 mm. Therefore, the combination of the air insulation depth and the air insulation pitch that can be adopted in this case is within the region of the part A hatched in FIG. 28. Within the region of the A portion, it is possible to achieve both the heat insulating performance and the productivity of the heat insulating structure 100.

To summarize the above, when the material of the first foamed heat insulating material 110 is the bead method polystyrene foam, it is desirable that the air heat insulating pitch is at least 53 mm and the air heat insulating depth is 15.5 mm or less. Further, especially when the high temperature heat source is large, it is more desirable that the air insulation pitch is 49 mm or less and the air insulation depth is 11 mm or less. Further, if the air insulation depth is set to 5.5 mm or less, even if the first foamed heat insulating material 110 is urethane foam, the amount of heat transfer can be suppressed as compared with the conventional heat insulating structure having no air heat insulating layer 101. At that time, the air insulation pitch is preferably 42 mm or less.

Even in the heat insulating structure 100 configured as described above, the same effect as that of the first embodiment can be obtained. Therefore, it is possible to select the material, various dimensions, etc. of the first foamed heat insulating material 110 according to the required heat insulating performance, manufacturing cost, and the like. The material of the first foamed heat insulating material 110 is not limited to the urethane foam and the polystyrene foam described above. Other foam insulation may be used. For other foamed heat insulating materials, the thickness and pitch of the air heat insulating portion may be determined in consideration of the foaming ratio, the amount of bending, the circumstances of the mold, and the like.

1 Hot water storage tank 10 Foam insulation 20 Outer shell 100 Insulation structure 101 Air insulation layer 110 First foam insulation 111 Concave 112 Convex 113 Foam insulation block 120 Second foam insulation 130 Vacuum heat insulating material

Claims (5)

A vacuum heat insulating material having a core material and an outer cover material that vacuum-seals and covers the core material,
A first foam heat insulating material having one side surface closely arranged on the vacuum heat insulating material and a recess formed on the one side surface.
The vacuum heat insulating material and the second foamed heat insulating material provided so as to cover the first foamed heat insulating material are provided.
In the first foamed heat insulating material, an air heat insulating layer is formed by the air trapped in the recess.
The air heat insulating layer is a heat insulating structure arranged on the high temperature heat source side of the vacuum heat insulating material. The first foam insulation material and the second foam insulation material are made of the same quality urethane foam.
The heat insulating structure according to claim 1, wherein the thickness of the air heat insulating layer is 8.5 mm or less. The first foamed heat insulating material is made of beaded polystyrene foam.
The heat insulating structure according to claim 1, wherein the thickness of the air heat insulating layer is 15.5 mm or less. The first foam heat insulating material having a recess formed on one side surface thereof is attached to the vacuum heat insulating material having a core material and an outer cover material that vacuum-seals and covers the core material, and the surface on which the recess is formed is the vacuum heat insulating material. Make it close to the side of the
The vacuum heat insulating material and the first foamed heat insulating material are covered with a second foamed heat insulating material different from the first foamed heat insulating material and integrally molded.
A method for manufacturing a heat insulating structure in which an air heat insulating layer is formed by air trapped in the recess in the first foamed heat insulating material. The method for manufacturing a heat insulating structure according to claim 4, wherein the first foamed heat insulating material is formed by connecting a plurality of heat insulating material parts.

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