Thermal insulation structure of a heat storage tank

Abstract

This invention provides a thermal insulation structure for a thermal storage tank that minimizes the land area used while maintaining the thermal insulation performance of the thermal storage tank, and also helps to reduce the construction costs of the thermal storage tank. [Solution] The system comprises a waterproof layer in the ground, a waterproof wall penetrating from the ground surface toward the waterproof layer, and a waterproof ground partitioned by the waterproof layer and the waterproof wall. The waterproof ground includes a heat storage tank formed by excavating the ground and a means for lowering the groundwater level to pump out groundwater from within the waterproof ground. The heat storage tank includes an insulating lid that closes the opening of the heat storage tank and a waterproof section positioned between the heat storage tank and the ground. The waterproof section includes a bottom slab made of reinforced concrete that forms the bottom surface of the heat storage tank and a retaining wall made of PC sheet piles that form the side walls of the heat storage tank and penetrate the waterproof layer. The retaining wall is held horizontally by bracing and walers attached via intermediate piles of earth retaining support erected at predetermined intervals within the heat storage tank.

Description

Technical Field

[0001] The present invention relates to a heat storage tank insulation structure installed underground, and particularly to a heat storage tank insulation structure that can minimize the installation location of the heat storage tank while maintaining the heat storage effect of the heat storage tank.

Background Art

[0002] Conventionally, a heat storage tank is constructed in the ground. In summer when the air temperature is high, hot water at about 90°C is produced by solar heat collection means such as solar panels, and the hot water is stored in the heat storage tank and insulated. In winter when the air temperature drops, the hot water is used as a heat source for heating. Such heat storage tanks have various configurations. For example, as described in Patent Document 1, it has a water barrier layer in the ground, a water barrier wall penetrating from the ground surface toward the water barrier layer, and a water barrier ground partitioned by the water barrier layer and the water barrier wall. The water barrier ground includes a heat storage tank formed by excavating the ground, a water barrier portion disposed between the heat storage tank and the ground, and a groundwater level lowering means for pumping out groundwater in the water barrier ground. The groundwater level lowering means penetrates the bottom of the heat storage tank of the heat storage tank and penetrates to near the lower end of the water barrier ground. There is also a heat storage tank as described in Patent Document 2, which has a heat-resistant water barrier sheet in contact with the excavated portion of the ground surface and a heat insulation lid in contact with the surface of the stored heat medium. From the ground surface to the surface, it has a predetermined margin height, and the outer edge portions of the heat-resistant water barrier sheet and the heat insulation lid have a folded-back portion that overlaps and is joined along the margin height. The folded-back portion has a pressure release portion that communicates the inside and outside of the heat storage tank. The pressure release portion has a first pipe portion extending from the folded-back portion and a second pipe portion formed by bending substantially at a right angle from the tip of the first pipe portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

[0004] However, according to the thermal storage tanks described in Patent Documents 1 and 2, the thermal storage tank's insulation structure is constructed by excavating the ground to form an inverted pyramid-shaped recess and covering the bottom surface and slope of the recess with a waterproof sheet. This presents the problem that it is necessary to excavate a wide area to form the slope, thus requiring a wide area of ​​land use for the thermal storage tank.

[0005] Furthermore, while Patent Document 2 describes a thermal storage tank in which reinforced concrete walls are cast as the sides to form a thermal storage tank that is substantially perpendicular to the ground surface, it is necessary to cover the inside of the thermal storage tank with a waterproof sheet in order to retain the hot water, which presents a problem in that it is difficult to reduce construction costs.

[0006] Therefore, the present invention has been made in view of the above problems, and aims to provide a thermal insulation structure for a thermal storage tank that can minimize the land use area while maintaining the thermal insulation performance of the thermal storage tank, and can also reduce the construction costs of the thermal storage tank. [Means for solving the problem]

[0007] The thermal insulation structure for a heat storage tank according to the present invention comprises a watertight layer in the ground, a watertight wall penetrating from the ground surface toward the watertight layer, and a watertight ground partitioned by the watertight layer and the watertight wall, wherein the watertight ground comprises a heat storage tank formed by excavating the ground and a means for lowering the groundwater level to pump out groundwater from within the watertight ground, wherein the heat storage tank comprises an insulating lid that closes the opening of the heat storage tank and a watertight section disposed between the heat storage tank and the ground, wherein the watertight section comprises a bottom slab made of reinforced concrete that forms the bottom surface of the heat storage tank and a retaining wall made of PC sheet piles that form the side walls of the heat storage tank and penetrate the watertight layer, wherein the retaining wall is held horizontally by bracing and walers attached via intermediate piles of earth retaining supports erected at predetermined intervals within the heat storage tank.

[0008] Furthermore, in the heat retention structure of the heat storage tank according to the present invention, it is preferable that a solar heat collection means is arranged on the upper part of the heat insulating lid.

[0009] Furthermore, in the heat retention structure for a heat storage tank according to the present invention, it is preferable that the solar heat collection means is held by a frame for the solar heat collection means erected between the earth retaining wall and the watertight wall, a support base for the solar heat collection means spanning across the frame for the solar heat collection means, and an intermediate pile of the earth retaining support structure that holds the support base for the solar heat collection means.

[0010] Furthermore, in the heat retention structure for the heat storage tank according to the present invention, it is preferable that the support base for the solar heat collection means is held via an insulating cap attached to the upper end of the intermediate pile of the earth retaining support structure.

[0011] Furthermore, in the heat retention structure for a heat storage tank according to the present invention, the heat insulating cap is preferably provided with a conical spacer member, and the side surface of the spacer member is preferably in contact with the heat insulating lid.

[0012] Furthermore, in the heat retention structure for the heat storage tank according to the present invention, it is preferable that the top of the heat insulating cap is provided with a dispersion shoe that is inserted into a mounting hole formed in the heat insulating lid and also contacts the support base for the solar heat collection means.

[0013] The above summary of the invention does not enumerate all the necessary features of the present invention, and subcombinations of these features may also constitute the invention. [Effects of the Invention]

[0014] According to the thermal insulation structure for a thermal storage tank of the present invention, the waterproof section comprises a bottom slab made of reinforced concrete that forms the bottom surface of the thermal storage tank, and a retaining wall made of PC sheet piles that form the side walls of the thermal storage tank and penetrate the waterproof layer. The retaining wall is held horizontally by bracing and walers attached via intermediate piles of the retaining wall support structure erected at predetermined intervals within the thermal storage tank. This minimizes the land use area and reduces costs while maintaining thermal insulation performance by reducing the amount of waterproof sheeting that was conventionally used.

[0015] Furthermore, by placing the solar heat collection system on top of the insulated lid of the heat storage tank, it becomes possible to further reduce the land area used.

[0016] Furthermore, even if the solar heat collection means is placed on top of the insulated lid, the insulated cap is placed between the support base for the solar heat collection means on which the solar heat collection means is mounted and the intermediate piles of the earth retaining support structure. As a result, the temperature of the hot water in the heat storage tank does not decrease due to transmission through the intermediate piles of the earth retaining support structure that are in contact with the hot water, and the heat retention performance of the conventional heat storage tank can be maintained. [Brief explanation of the drawing]

[0017] [Figure 1] A perspective view of a heat storage tank having an insulation structure according to this embodiment. [Figure 2] Cross-sectional view AA in Figure 1. [Figure 3] Cross-sectional view of the heat storage tank's insulating lid according to this embodiment. [Figure 4] Enlarged view of section B in Figure 2. [Figure 5] Cross-sectional view of CC in Figure 4. [Modes for carrying out the invention]

[0018] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments are not intended to limit the invention as described in each claim, and not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention.

[0019] FIG. 1 is a perspective view of a heat storage tank having a heat insulation structure of a heat storage tank according to the present embodiment, FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1, FIG. 3 is a cross-sectional view of a heat insulation lid of the heat storage tank according to the present embodiment, FIG. 4 is an enlarged view of part B in FIG. 2, and FIG. 5 is a cross-sectional view taken along line C-C in FIG. 4.

[0020] As shown in FIG. 1, the heat storage tank 1 according to the present embodiment is a heat storage tank having a rectangular upper surface with a side length of about 90 m, and solar heat collection means 2 for producing and supplying hot water is arranged on a heat insulation lid 13 (to be described later) of the heat storage tank 1. The solar heat collection means 2 may adopt any configuration as long as it can produce hot water as a heat medium. For example, it is suitable to be configured as a solar heat plant using solar heat panels.

[0021] In the heat storage tank 1 according to the present embodiment, hot water W serving as a heat medium is stored in the heat storage tank 1 from the solar heat collection means 2 arranged on the heat insulation lid 13 via a hot water supply device 5. The hot water supply device 5 has various conventionally well-known configurations. For example, it includes a pump, a water supply pipe, and the like. The hot water supply device 5 is preferably installed based on a bottom plate 21 (to be described later).

[0022] As shown in FIG. 2, the heat storage tank 1 according to the present embodiment suppresses a decrease in the temperature of hot water due to contact with groundwater even in a place where the groundwater level 6 is high. Specifically, it has a water barrier layer 3 in the ground G, a water barrier wall 11 penetrating into the water barrier layer 3 in the ground G, and a water barrier ground 4 partitioned by the water barrier layer 3 and the water barrier wall 11. The water barrier ground 4 includes a heat storage tank 1 formed by excavating the ground G, a water barrier portion 20 arranged between the heat storage tank 1 and the ground G, and a groundwater level lowering means 12 for pumping out groundwater in the water barrier ground 4.

[0023] The water barrier layer 3 may be any layer as long as it has water barrier properties. For example, it is suitable to use a water barrier layer made of cohesive soil or the like. Also, when such cohesive soil is not within a predetermined depth, artificial ground improvement work may be performed using a deep mixing treatment method or the like to form the water barrier layer 3.

[0024] The heat storage tank 1 is preferably formed by excavating the ground G. The sides of the heat storage tank 1 are constructed of retaining walls 22 made of PC sheet piles driven so as to penetrate the waterproof layer 3, and the bottom of the heat storage tank 1 is provided with a reinforced concrete base plate 21. The base plate 21 is preferably made of reinforced concrete with a thickness of 30 cm or more.

[0025] The retaining wall 22 is supported horizontally by bracing 24 and waling 25, which are attached via a plurality of intermediate piles 23 of the retaining wall support system that are driven through the base slab 21 at predetermined intervals. As shown in Figure 5, H-shaped steel or the like is preferably used for the intermediate piles 23 of the retaining wall support system. The base slab 21 is driven in such a way that it also serves as the lowest bracing of the bracing 24 that supports the retaining wall 22, thereby supporting the retaining wall 22 horizontally.

[0026] The waterproof section 20 is composed of a bottom plate 21 and a retaining wall 22 that form the side walls and bottom surface of the heat storage tank 1. In addition, at least one location in the retaining wall 22 is a water pumping communication pipe 26 that is located near the waterproof layer 3 and penetrates the inside and outside of the retaining wall 22 to the heat storage tank 1.

[0027] The groundwater level lowering means 12 preferably employs a deep well. The groundwater level lowering means 12 is preferably positioned between the heat storage tank 1 and the impermeable wall 11, and is equipped with a pipe section that penetrates to near the lower end of the impermeable ground 4 and a pumping means such as a pump that draws up groundwater from the lower end of the pipe section. As shown in Figure 2, the lower end of the groundwater level lowering means 12 reaches the impermeable layer 3, and groundwater flowing through the impermeable ground 4 can be pumped out of the impermeable ground 4 by the pumping means. Here, the area near the lower end of the impermeable ground 4 is preferably defined as a distance of approximately 3 m or more between the lower end of the groundwater level lowering means 12 and the bottom plate 21 of the heat storage tank 1, and it is not necessary for the groundwater level lowering means 12 to penetrate or contact the impermeable ground 4.

[0028] Because the groundwater level lowering means 12 is arranged in this manner, if the groundwater level of the impermeable ground 4 is so high that it cannot form a vertical separation distance of approximately 3m or more from the bottom slab 21 of the heat storage tank 1, the pumping means is driven to pump up the groundwater in the impermeable ground 4 and lower the groundwater level 6 of the impermeable ground 4 to a position where the separation distance from the bottom slab 21 of the heat storage tank 1 is 3m or more. By lowering the groundwater level 6 of the impermeable ground 4 in this way, it is possible to prevent the heat storage tank 1 from being cooled by the groundwater, thereby improving the heat retention effect of the impermeable ground 4.

[0029] Furthermore, since a water pumping pipe 26 is formed in the retaining wall 22, it is possible to reliably pump up groundwater from the impermeable ground 4.

[0030] Furthermore, since the waterproof section 20 includes a retaining wall 22 made of PC sheet piles and a bottom slab 21 made of reinforced concrete, it is possible to minimize heat dissipation and ensure a waterproofing effect, and the waterproofing sheets that were used on the sides and bottom of conventional heat storage tanks can be reduced, contributing to cost reduction.

[0031] Furthermore, the top surface of the heat storage tank 1 has an opening to the ground surface by excavating the ground G, but this opening is closed by an insulating lid 13 that has insulating properties. The insulating lid 13 can be made of any material as long as it can keep the hot water stored in the heat storage tank 1 warm, but for example, as shown in Figure 3, an insulating sheet can be used, which is made by laminating an insulating material 14 made of expanded polystyrene or the like with a surface 15 made of polyethylene or the like.

[0032] The solar thermal energy collection means 2 is positioned on a solar thermal energy collection means frame 31, which is driven between the retaining wall 22 and the retaining wall 11 in the impermeable ground 4, and on a solar thermal energy collection means support base 32, which is supported by the retaining wall support intermediate pile 23. The solar thermal energy collection means support base 32 is positioned to span across the solar thermal energy collection means frame 31.

[0033] Furthermore, the support base 32 for the solar thermal collection means is supported on the intermediate pile 23 of the earth retaining support structure via a concrete insulating cap 40. As shown in Figures 4 and 5, the insulating cap 40 is a generally conical member and has a mounting hole 41 into which the tip of the intermediate pile 23 of the earth retaining support structure is inserted, and a side surface 42 formed to widen from the top to the bottom of the insulating cap 40.

[0034] Preferably, grout or the like is injected into the gap between the mounting hole 41 and the intermediate pile 23 of the earth retaining support structure to integrate the intermediate pile 23 of the earth retaining support structure and the heat insulating cap 40.

[0035] A rubber dispersing shoe 50 is attached to the top of the insulating cap 40, and the dispersing shoe 50 contacts the support base 32 for the solar heat collection means to support the vertical load. Preferably, the dispersing shoe 50 is inserted into a through hole 16 formed in the insulating lid 13.

[0036] Furthermore, the side surface 42 of the insulating cap 40 is positioned to abut against the insulating lid 13. When the water level in the heat storage tank 1 fluctuates due to an earthquake or other event, causing shaking, the water generated by the shaking enters the space between the side surface 42 and the insulating lid 13, thereby absorbing the fluctuation in the water level.

[0037] The heat storage tank 1 configured in this embodiment has a heat insulation structure in which the solar heat collection means 2 is installed on top of the heat storage tank 1, which reduces the land use area of ​​the solar heat collection means 2, making it possible to reduce it by approximately 1 / 4 compared to conventional land use areas.

[0038] Furthermore, in this embodiment, the heat retention structure of the heat storage tank 1 is constructed with retaining plates for the side walls of the heat storage tank 1, so the surface area of ​​the heat storage tank 1 and the excavated surface area are almost the same, and the land use area can be minimized compared to the conventional method of forming a slope.

[0039] Furthermore, since the retaining wall 22 penetrates the impermeable layer 3 and comes into contact with groundwater, heat is easily radiated through the retaining wall from the point of contact with groundwater. However, in the heat retention structure of the heat storage tank 1 according to this embodiment, PC sheet piles, which have a lower thermal conductivity than conventionally used steel sheet piles, are used for the retaining wall 22. Therefore, the amount of heat radiated can be minimized, and the heat retention performance can be maintained.

[0040] Furthermore, in this embodiment, the heat storage tank 1's insulation structure utilizes the bottom plate 21 of the heat storage tank 1 as the lowest bracing beam of the retaining wall 22, thereby reducing the number of components and thus lowering costs.

[0041] Furthermore, the heat retention structure of the heat storage tank 1 according to this embodiment is composed of a watertight section 20 consisting of a retaining wall 22 made of PC sheet piles for the side walls and bottom of the heat storage tank 1, and a bottom slab 21 made of reinforced concrete for the floor plate. Therefore, the watertight function of the PC sheet piles and reinforced concrete makes it possible to reduce the amount of watertight sheets that were conventionally used, thus contributing to cost reduction.

[0042] Furthermore, in the thermal insulation structure of the heat storage tank 1 according to this embodiment, the support base 32 for the solar thermal collection means 2 on which the solar thermal collection means 2 is placed is held by an intermediate pile 23 of the earth retaining shoring, which is an intermediate pile of the earth retaining excavation. This reduces the amount of H-shaped steel used as the foundation for the support base 32 for the solar thermal collection means, thus contributing to cost reduction.

[0043] Furthermore, in this embodiment, the heat retention structure of the heat storage tank 1 also serves as the foundation for the hot water supply device 5 with a reinforced concrete bottom slab 21, thus reducing the amount of H-shaped steel used as the foundation for the hot water supply device 5 and contributing to cost reduction.

[0044] Furthermore, in the thermal insulation structure of the thermal storage tank 1 according to this embodiment, the intermediate piles 23 of the earth retaining support structure serve as the foundation for the support base 32 for the solar thermal collection means. Since the intermediate piles 23 of the earth retaining support structure, which are in contact with the hot water, penetrate the insulating lid 13, heat from the thermal storage tank 1 is easily transferred to the support base 32 for the solar thermal collection means via the intermediate piles 23 of the earth retaining support structure. However, an insulating cap 40 is provided between the support base 32 for the solar thermal collection means and the intermediate piles 23 of the earth retaining support structure. This insulating cap 40 blocks the transfer of heat while allowing sectional forces such as axial forces to be transferred, thereby maintaining the thermal insulation performance of the thermal storage tank 1.

[0045] Furthermore, since the insulating cap 40 is a conical space member, if the hot water in the heat storage tank 1 shakes (sloshing) due to an earthquake or the like, the insulating lid 13 will also move up and down in accordance with the sloshing. However, because the insulating lid 13 is positioned so as to be in contact with the conical side surface, it can follow the up and down movement of the insulating lid 13, thus preventing damage to the insulating lid 13 due to sloshing caused by earthquakes or the like.

[0046] Furthermore, although the heat retention structure of the heat storage tank 1 according to the present embodiment described above has been explained in the case where the solar heat collection means 2 is a solar thermal panel, it is possible to use various low-power heat collection means other than solar thermal panels. It is clear from the description of the claims that such modified or improved forms may also be included in the technical scope of the present invention. [Explanation of Symbols]

[0047] 1 Heat storage tank, 2 Solar heat collection means, 3 Impermeable layer, 4 Impermeable ground, 5 Hot water supply device, 6 Groundwater level, 11 Impermeable wall, 12 Groundwater level lowering means, 13 Insulating cover, 14 Insulating material, 15 Skin, 16 Through hole, 20 Impermeable section, 21 Bottom slab, 22 Retaining wall, 23 Retaining wall intermediate pile, 24 Bracing, 25 Waler, 26 Pumping connecting pipe, 31 Frame for solar heat collection means, 32 Support base for solar heat collection means, 40 Insulating cap, 41 Mounting hole, 42 Side, 50 Dispersed foot G Ground.

Claims

1. The impermeable layer within the ground, A watertight wall that penetrates from the ground surface toward the aforementioned watertight layer, The ground is partitioned by the aforementioned impermeable layer and the aforementioned impermeable wall, The impermeable ground comprises a heat storage tank formed by excavating the ground and a means for lowering the groundwater level to pump out groundwater from within the impermeable ground. The heat storage tank comprises an insulating lid that closes the opening of the heat storage tank and a watertight section disposed between the heat storage tank and the ground. The waterproof section comprises a bottom slab made of reinforced concrete that forms the bottom surface of the heat storage tank, and an earth retaining wall made of PC sheet piles that forms the side wall of the heat storage tank and penetrates the waterproof layer. The heat retention structure for a heat storage tank is characterized in that the earth retaining wall is held horizontally by bracing and walers attached via intermediate piles of earth retaining support erected at predetermined intervals within the heat storage tank.

2. In the heat retention structure of the heat storage tank according to claim 1, A heat storage tank insulation structure characterized in that a solar heat collection means is arranged on the upper part of the aforementioned heat insulating lid.

3. In the heat retention structure of the heat storage tank according to claim 2, The thermal insulation structure for a heat storage tank is characterized in that the solar thermal collection means is held by a frame for solar thermal collection means erected between the earth retaining wall and the watertight wall, a support base for solar thermal collection means spanning across the frame for solar thermal collection means, and intermediate piles of the earth retaining support structure that hold the support base for solar thermal collection means.

4. In the heat retention structure of the heat storage tank according to claim 3, The thermal insulation structure for a heat storage tank is characterized in that the support base for the solar thermal collection means is held via an insulating cap attached to the upper end of the intermediate pile of the earth retaining support structure.

5. In the heat retention structure of the heat storage tank according to claim 4, The aforementioned heat-insulating cap is equipped with a conical spacer member, A heat retention structure for a heat storage tank, characterized in that the side surface of the spacer member is in contact with the heat insulating lid.

6. In the heat retention structure of the heat storage tank according to claim 5, The heat retention structure for a heat storage tank is characterized in that the top of the heat-insulating cap is provided with a dispersion shoe that is inserted into a mounting hole formed in the heat-insulating lid and also contacts the support base for the solar heat collection means.

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