JPH0554028B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a low-temperature storage warehouse that cools the interior of the warehouse by freezing the ground using a heat pipe.

[Conventional technology]

Generally, when storing grains such as rice, food, etc., it is required to store them in an environment of constant low temperature and constant humidity.

Conventionally, this type of storage facility has been applied, for example, to a low-temperature storage warehouse that uses a refrigerator to maintain the interior at a constant temperature, but the equipment cost (initial cost) and running cost are high. is becoming high.

[Problem that the invention seeks to solve]

As a result of intensive research to solve these problems, the present applicant and others have found that if cold energy in winter is stored in the form of frozen soil and this cold energy is supplied in warm summer months, it will be possible to avoid using conventional refrigerators. The idea was that the initial cost and running cost would be lower compared to storage.

However, the reality is that if artificial frozen soil is created using forced cooling using electricity, it is not possible to achieve a significant reduction in initial costs and running costs.

Therefore, the applicants conducted various experiments on the creation of frozen soil using heat pipes, and researched the possibility of using it as a low-temperature storage storage. It is possible to build frozen soil in the ground, and the form of latent heat is ideal for storing natural cold heat underground for a long time via heat pipes, and for this purpose, the ground is preferable to bedrock. Among the ground types, we learned that clay soil, which has a high moisture content, is generally more suitable than sandy soil, and that if the thickness of frozen soil is 1.5 m or more, frozen soil will remain even after one year has passed. .

However, if frozen soil is created by cooling the ground with heat pipes, the cold storage facility will be ready for use after the construction of the cold storage facility and after waiting for frozen soil to form around it. A certain period of time was required. Furthermore, the heat transport capacity of a heat pipe is at its maximum when it is buried in the ground, and gradually decreases thereafter. Therefore, it takes a long time to create a predetermined thickness of permafrost layer that can be maintained as frozen soil during the warm season, and in most cases it is not possible to create a predetermined thickness of permafrost layer in one winter. .

The present invention was made based on this knowledge, and uses heat pipes to store cold energy in the winter underground, and uses this as a cold heat source to maintain the inside of the refrigerator at a low temperature. The purpose of the present invention is to provide a method of constructing a low-temperature storage facility, which can significantly reduce costs and running costs, in a ready-to-use state and in one winter.

[Means for solving problems]

This invention involves excavating an excavation hole that opens to the outside air on the surface of the ground, and
A step of forming an inclined surface with an upward slope toward the opening, and after the step of excavating the borehole,
During cold periods such as winter, the inside of this excavated hole is backfilled with soil to a predetermined thickness, and this backfilled soil is frozen by natural cold air from the aforementioned excavated hole, and then the soil is poured on top of this frozen soil. By sequentially backfilling soil to a predetermined thickness and freezing this soil, a frozen soil layer is formed inside the excavated hole, and during the process of forming this frozen soil layer, the side wall of the excavated hole is arranging a heat pipe in the frozen soil layer so that the lower end reaches the bottom of the excavation hole while following the heat pipe;
After the step of forming a frozen soil layer, the method for constructing a low temperature storage warehouse comprises the step of constructing a roof on the ground surrounding the excavation hole to cover the top surface of the excavation hole,
This solves the above problems.

[Effect]

In this invention, a frozen soil layer is formed by repeating the process of freezing while backfilling the soil inside the excavated hole, so that the cold storage is ready for use immediately after construction, and can be used even during winter. Since the soil is backfilled to a predetermined thickness and frozen during the cold season, a frozen layer can be formed in a short period of time.
In this frozen soil layer, supercooled outside air energy is stored as cold heat during cold periods such as winter by heat pipes disposed in the frozen soil layer.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are diagrams showing a low-temperature storage facility constructed according to a method for constructing a low-temperature storage facility according to an embodiment of the present invention. In Figures 1 and 2, reference numeral A indicates a low-temperature storage facility opened to the outside air made on the surface of the ground G, and reference numeral 1 indicates the interior of this low-temperature storage facility A. It is formed in a rectangular hole to constitute a storage place for food, etc. In the illustrated example, the rectangular bottom 2 of the interior 1 is formed flat, and the side wall 3 around the bottom 2 is flat. It is formed on an inclined surface that slopes upward toward the opening.

Further, a floor slab 4 is constructed on the upper surface of the bottom portion 2 using concrete or crushed stone, and sandbags 5 are stacked on the sloped side wall portion 3 in order from the bottom portion 2. Further, on the upper surface of the embankment 6 around the low-temperature storage A, a concrete foundation 8 is formed on which a roof 7, which will be described later, is placed.

A frozen layer F is formed on the ground G around the interior 1 of the low-temperature storage warehouse A so as to surround the interior 1. A plurality of heat pipes 10 that cool the interior 1 of the low-temperature storage A by freezing are installed at equal intervals along the periphery of the interior 1. Between this frozen layer F and the surrounding ground G, an impermeable membrane 13 blocks water from flowing into and out of the frozen layer F so that the water contained in the frozen layer F does not leak into the ground G. .

As shown in FIG. 1, this heat pipe 10 is constructed so that a working fluid is sealed in a long cylindrical airtight container 11 that is sufficiently deaerated, and heat transfer occurs as the phase of the fluid changes. In the illustrated example, the upper end 11a of the airtight container 11 protrudes from the base 8, the lower side thereof extends parallel to the side wall 3 to the vicinity of the bottom, and the tip (lower end) 11b of the airtight container 11 protrudes from the base 8 (floor 2). ) It has a buried structure that extends to the bottom. In addition, a plurality of heat receiving and dissipating fins 12 are provided protruding along the length of the upper outer periphery of the airtight container 11 exposed to the outside air in order to increase the efficiency of heat transfer.

In the illustrated example, the lower ends of the left and right heat pipes 10 (lower ends 11b of the airtight container 11) are arranged alternately so as not to interfere with each other under the floor, but this arrangement structure is limited to this. For example, it may be a structure in which these are slightly wrapped.

The roof 7 covering the upper surface of the refrigerator interior 1 is placed on the foundation 8 around the refrigerator interior 1, and has a structure in which a roof plate 7b having a heat-insulating structure is placed on a beam 7a having a truss structure. Note that the structure of the roof 7 is not limited to this one, and may have another structure.

Reference numeral 15 in the figure indicates a heat insulating material laid on the outer surface of the embankment, and is provided especially when the outside air temperature is high, such as in summer.

Furthermore, Fig. 2 shows a state in which a plurality of low temperature storages A having such a structure are arranged side by side (in a group).
This arrangement reduces the heat load,
This is preferable because it is efficient.

Next, a low temperature storage warehouse A which is an embodiment of this invention
The construction method and its usage will be explained with reference to FIGS. 1 to 3.

First, the construction method for low temperature storage A will be explained in order of each step.

(i) Step 1 (Figure 3a) The surface of the ground G that will be the storage location is excavated to form an excavated hole 16 that opens to the outside air, and the side wall of this excavated hole 16 is inserted into the opening. It is formed into a slope that slopes upward as you go towards the area. Here, if the groundwater level of the ground G is lower than the bottom of the excavation hole 16, or if the water content ratio of the ground G is small, then in order to prevent water in the soil for backfilling, which will be described later, from seeping into the ground G, A water-impermeable membrane 13 covers the surface of the excavated hole 16.
cover with

(ii) Step 2 (Fig. 3b) During a cold season such as winter, the inside of the excavated hole 16 is backfilled with soil 17 to a predetermined thickness, and this soil 17 is frozen by natural cold air from the excavated hole 16. . This process is repeated to form several layers of frozen soil F within the excavated hole 16 up to the depth at which the heat pipe 10 is disposed. It is preferable that the soil 17 to be backfilled contains a saturated amount of water in order to promote freezing after backfilling and to facilitate maintenance of the frozen soil layer F after construction of the cold storage facility A. The water content ratio of No. 17 may be adjusted as appropriate depending on the construction conditions and the like. In addition, the thickness of the soil 17 to be backfilled at one time may be determined as appropriate depending on the construction conditions, etc., but in order to ensure that the backfilled soil 17 is frozen uniformly and quickly, the thickness should be filled in approximately 10 to 20 cm increments. It is preferable to return it.

(iii) Step 3 (Fig. 3c) In the frozen soil layer F, the airtight container 11 extends along the side wall of the excavation hole 16, and its lower end 11b reaches the bottom of the excavation hole 16. heat pipe 1
Set 0. After that, similarly to step 2, the soil 17 is backfilled to a predetermined thickness inside the frozen soil layer F, and this soil 17 is frozen by natural cold air from the excavated hole 16 and cooling from the heat pipe 10.
By repeating this process, a frozen soil layer F with a thickness sufficient to maintain the frozen soil layer F around the cold storage facility A is finally formed throughout the year, and this frozen soil layer F
Inside 1 of low temperature storage A is formed inside.

Here, the thickness of the frozen soil layer F that can be formed in one winter according to the above process reaches 3 to 4 m if the cumulative cold temperature is greater than 500°C/day, so it is sufficient to maintain it throughout the year. It can be said that one winter is sufficient to form a thick frozen layer F. Further, if there is a problem with the humidity or airtightness of the interior 1 due to evaporation of moisture in the soil 17 to be backfilled, the surface of the frozen soil layer F is also covered with a water-impermeable film 13.

(iv) Step 4 (Fig. 3 d) Sandbags 5 are stacked vertically along the side wall 3 of the warehouse interior 1, concrete is placed on the bottom 2 of the warehouse interior 1, and the floor slab 4 is placed. Along with construction, the foundation part 8
form. When a roof 7 is attached to the upper surface of this foundation 8, a low temperature storage A as shown in FIG. 1 is constructed.

Low-temperature storage A with such a configuration has a sufficiently thick frozen layer F formed around it at the time of construction, so it is ready for immediate use, but it also suffers from heat damage during cold periods such as winter. By cooling the upper part of the pipe 10 with cold air and cooling and freezing the earthen wall F around the heat pipe 10, a frozen soil layer F is built and maintained around the inside of the refrigerator 1, and supercooled outside air energy is stored.

That is, when the upper part of the heat pipe 10 is cooled by cold air in winter, the working fluid in the airtight container 11 condenses and becomes a liquid, which falls by gravity along the pipe wall of the airtight container. As a result, cold heat is carried to the lower part, and the frozen soil layer F around the airtight container 11 is cooled and frozen by this carried cold heat.
A frozen soil layer F is constructed and maintained around the airtight container 11, as shown in FIG. This phenomenon is repeated in winter, and a frozen layer F is built around the heat pipe 10, and supercooled outside air energy (cold energy) is stored in the frozen layer F and ice.

On the other hand, in warm spring and summer,
The local cold storage thermal energy in the frozen soil layer F is released,
The temperature inside the refrigerator 1 is maintained at a low temperature.

The low temperature storage A is constructed by the construction method described above. Here, this low-temperature storage A is constructed while forming a frozen layer F inside the excavated hole 16, so when the low-temperature storage A is completed, there is already a sufficiently thick frozen layer around the low-temperature storage amount A. F is formed. Therefore, this low-temperature storage A can be used to store food and the like in the interior 1 at the same time as it is completed. In addition, the formation of the frozen soil layer F is carried out during cold seasons such as winter, and the soil to be backfilled is divided into predetermined thicknesses that facilitate the formation of the frozen soil layer F, and after being backfilled, it is sequentially frozen. Therefore, the formation of frozen soil layer F is carried out in a short period of time, and if the conditions are right, it is possible to form frozen soil layer F of sufficient thickness in one winter.

In addition, in the construction of this low-temperature storage facility A, the ground G is excavated from the surface, the heat pipes 10 are installed while backfilling with soil 17, and the roof 7 is placed on the upper surface of the ground G.
It is a simple work such as constructing a heat pipe 10, and does not require special techniques (boring, etc.) for the construction (for example, installing the heat pipe 10).In addition, the maintenance-free heat pipe 10 can be used instead of a refrigerator to provide cooling and heating. Since cold storage A is easy to install and maintain, the initial cost is low.
It is possible to significantly reduce both running costs.

In the low temperature storage A of the embodiment, the side wall portion 3
Since it is formed on an inclined surface, it is possible to support it with inexpensive materials such as sandbags 5, and the cost of constructing the storage place can be reduced.

In the above-mentioned embodiment, the interior 1 itself is used as a storage place and the roof 7 is attached above it. However, it is also possible to install large-diameter corrugated pipes, box culverts, etc. in this interior 1 and use these as a storage place. It is also possible to have a backfilled structure. In this case, while backfilling soil 17 as described above, this soil 1
If 7 is frozen, rapid construction and immediate use are possible.

〔Effect of the invention〕

As explained in detail above, according to the present invention, when the cold storage facility is completed, a sufficiently thick layer of frozen soil has already been formed around it, so that the cold storage facility is ready for use upon completion. In addition, the formation of the frozen soil layer is carried out during cold seasons such as winter, and the soil to be backfilled is divided into predetermined thicknesses and frozen sequentially after being backfilled.
The formation of a frozen layer takes place in a short period of time, and if the conditions are right, it is possible to form a frozen layer of sufficient thickness in one winter. After the low-temperature storage is constructed, the energy of the surrounding supercooled outside air can be used to form and maintain frozen soil due to the action of the heat pipe. Therefore, during the warm spring and summer months, the cold thermal energy stored in the frozen ground is released, thereby maintaining the temperature inside the low-temperature storage at a low temperature.

In addition, the construction of this low-temperature storage facility itself is a simple task and does not require any special technology.
In addition, since the cold heat source is composed of a maintenance-free heat pipe instead of a refrigerator, the installation and maintenance of the low-temperature storage is easy, which significantly reduces both the initial cost and running cost of the low-temperature storage. is possible.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a low-temperature storage facility constructed according to the method for constructing a low-temperature storage facility according to an embodiment of the present invention, FIG. 2 is a perspective view showing a state in which the low-temperature storage facilities are arranged in groups, and FIG. The figure is a diagram illustrating a method of constructing a low temperature storage warehouse according to an embodiment of the present invention. A... Low temperature storage, F... Frozen soil layer, G... Ground, 7... Roof, 10... Heat pipe, 11b
... lower end of heat pipe, 16 ... drilling hole, 17 ...
…soil.

Claims (1)

[Claims] 1. A step of excavating an excavation hole that opens to the outside air on the surface of the ground, and forming the side wall of this excavation hole into an inclined surface that slopes upward toward the opening; After the process, during the cold season such as winter, the inside of this excavated hole is backfilled with soil to a predetermined thickness, and this backfilled soil is frozen by natural cold air from the aforementioned excavated hole, and then this frozen soil is A process of forming a frozen soil layer inside the excavated hole by sequentially backfilling soil to a predetermined thickness and freezing this soil, and a process of forming a frozen soil layer inside the excavated hole. A step of arranging a heat pipe in the frozen soil layer so that the lower end reaches the bottom of the excavation hole along the side wall, and after the step of forming the frozen soil layer, installing the heat pipe on the ground around the excavation hole. A method for constructing a cold storage facility, which includes the step of constructing a roof to cover the top of the hole.