CN111854227A

CN111854227A - High-heat-conductivity energy pile and manufacturing method thereof

Info

Publication number: CN111854227A
Application number: CN202010634775.XA
Authority: CN
Inventors: 王宇虓; 时刚; 王维蒙; 李超越; 朱邦华; 田孝伟
Original assignee: Zhengzhou University
Current assignee: Zhengzhou University
Priority date: 2020-07-03
Filing date: 2020-07-03
Publication date: 2020-10-30
Anticipated expiration: 2040-07-03
Also published as: CN111854227B

Abstract

The invention relates to a high-heat-conductivity energy pile and a manufacturing method thereof, wherein the high-heat-conductivity energy pile comprises a concrete pile body, a steel bar framework and a heat exchange tube structure, wherein the steel bar framework is embedded in the concrete pile body, the steel bar framework is a cylindrical steel bar net, and the heat exchange tube structure comprises a plurality of heat exchange tubes fixedly arranged on the inner side of the steel bar net, a liquid inlet convergence cavity connected with liquid inlets of the heat exchange tubes, a liquid inlet tube connected with the liquid inlet convergence cavity, a liquid outlet convergence cavity connected with liquid outlets of the heat exchange tubes and a liquid outlet tube connected with the liquid outlet convergence cavity. According to the high-heat-conductivity energy pile, the heat exchange tube structure is fixed on the inner side of the steel reinforcement framework, so that the heat exchange tube structure and the steel reinforcement framework form a connected whole, the stability of the energy pile is enhanced, the plurality of heat exchange tubes form a general branch structure through the liquid inlet gathering cavity and the liquid outlet gathering cavity, liquid contacts heated concrete with a larger area through the plurality of heat exchange tubes, heat is gathered conveniently, and the temperature of the liquid is increased rapidly.

Description

High-heat-conductivity energy pile and manufacturing method thereof

Technical Field

The invention relates to the field of buildings, in particular to a high-heat-conductivity energy pile and a manufacturing method thereof.

Background

Shallow geothermal energy is more and more concerned by society as a clean, efficient and environment-friendly renewable energy source. The ground source heat pump system completes heat exchange with the rock-soil body through the heat exchanger buried underground, so as to refrigerate or heat the building and realize utilization of shallow geothermal energy. The energy pile is used as a novel buried pipe form of the ground source heat pump, and a circulating pipeline is buried in a pile foundation of a building. Compared with the traditional drilling buried pipe, the heat exchanger increases the contact area between the heat exchanger and the soil body, fully utilizes the higher volume specific heat and the heat conductivity coefficient of concrete to improve the heat exchange efficiency, saves the underground space and the engineering cost, has the design concept meeting the development trend of energy conservation, emission reduction, environmental protection and no pollution, and has good development prospect and popularization value

At present, although the application of the energy pile is more extensive than before, the research on the technology is still lagged, the heat exchange efficiency of the energy pile is improved by optimizing the type and the operation mode of a heat exchanger, and the like, so that the utilization efficiency of the geothermal energy of a shallow layer cannot be further improved, and the comprehensive popularization and development of the energy pile are hindered. Therefore, the research on how to efficiently improve the heat exchange performance of the energy pile has important practical significance and social significance.

Disclosure of Invention

The invention aims to provide a high-heat-conductivity energy pile and a manufacturing method thereof.

The scheme of the invention is as follows:

the utility model provides a high heat conduction energy stake, includes concrete pile body, buries steel bar framework and the heat exchange tube structure in concrete pile body underground, steel bar framework is the reinforcing bar net of tube-shape, the heat exchange tube structure assembles the chamber, connects the feed liquor of feed liquor convergence chamber, connects each heat exchange tube liquid outlet and assembles the chamber and connect the drain pipe that goes out the liquid and assemble the chamber including setting firmly in the inboard many heat exchange tubes of reinforcing bar net, connecting each heat exchange tube liquid inlet.

Preferably, the heat exchange tubes are U-shaped heat exchange tubes or inverted-U-shaped heat exchange tubes, the U-shaped heat exchange tubes or the inverted-U-shaped heat exchange tubes are arranged in parallel in the reinforcing mesh, the distance between two heat exchange arms of each U-shaped heat exchange tube or each inverted-U-shaped heat exchange tube is gradually reduced from the middle part to two sides of the reinforcing mesh, a liquid inlet of each U-shaped heat exchange tube or each inverted-U-shaped heat exchange tube is communicated with the liquid inlet gathering cavity, a liquid outlet of each U-shaped heat exchange tube or each inverted-U-shaped heat exchange tube is communicated with the liquid outlet gathering cavity, and the liquid outlet gathering cavity and.

Preferably, a plurality of aluminum annular fins are fixedly welded on the U-shaped heat exchange tube or the inverted-V-shaped heat exchange tube.

Preferably, the heat exchange tubes comprise a plurality of U-shaped heat exchange tubes and a spiral heat exchange tube, the U-shaped heat exchange tubes are circumferentially distributed in a reinforcing bar net, each U-shaped heat exchange tube is radially arranged along the reinforcing bar net, the spiral heat exchange tubes are respectively wound and fixed on outer ring heat exchange arms of the U-shaped heat exchange tubes and inner ring heat exchange arms of the U-shaped heat exchange tubes, liquid inlets of the heat exchange tubes are lower than liquid outlets, liquid inlet gathering cavities connected with the liquid inlets of the heat exchange tubes and liquid outlet gathering cavities connected with the liquid outlets of the heat exchange tubes are annular boxes, and the inner diameters of the liquid inlet gathering cavities are larger than the outer diameters of the liquid.

Preferably, a plurality of aluminum annular fins are fixedly welded on the U-shaped heat exchange tube and the spiral heat exchange tube.

A manufacturing method of a high-heat-conductivity energy pile comprises the following steps: step 1, fixing the heat exchange tube according to any one of claims 1 to 5 on the inner side of a cylindrical mesh reinforcement, inserting the mesh reinforcement and the heat exchange tube into a pile hole together by a hoisting machine, wherein gaps are reserved between the bottom of the mesh reinforcement and the heat exchange tube and the bottom of the pile hole as well as between the circumference of the mesh reinforcement and the side wall of the pile hole;

Step 2, adding high thermal conductivity concrete into the pile hole to form a pile body, wherein the liquid inlet gathering cavity and the liquid outlet gathering cavity are both higher than the upper surface of the high thermal conductivity concrete, and then curing, wherein the high thermal conductivity concrete comprises the following components in parts by weight: 15-20 parts of cement, 30-35 parts of sand, 55-60 parts of broken stone, 10-11 parts of water, 0.03-0.04 part of water reducing agent and 1.5-4.5 parts of silicon carbide.

Preferably, the mesh number of the silicon carbide is 11-125 meshes.

Preferably, the mesh number of the silicon carbide is 12 meshes.

Preferably, the sand is river sand, the grading is medium sand, the fineness modulus of the sand is 2.3-3.0, and the bulk density is 1480-1560 kg/m³。

Preferably, the broken stone is limestone or granite broken stone and is formed by grading broken stones with the grain sizes of 5-10 mm, 10-20 mm and 20-30 mm according to the mass ratio of 3:4:3 or 2:5: 3.

The invention has the beneficial effects that: high heat conduction energy stake, heat exchange tube structure fix in the framework of steel reinforcement inboard for heat exchange tube structure and framework of steel reinforcement form a continuous whole, to having strengthened the stability of energy stake, many heat exchange tubes assemble the chamber through the feed liquor and go out the liquid and assemble the chamber and form total branch total structure, and liquid is convenient for gather the heat through the concrete that is heated of many heat exchange tube contact bigger areas, promotes the liquid temperature fast.

Furthermore, each U-shaped heat exchange tube or the inverted-U-shaped heat exchange tube is arranged in parallel in the steel bar mesh, and the distance between two heat exchange arms of each U-shaped heat exchange tube or the inverted-U-shaped heat exchange tube is gradually reduced from the middle part to two sides of the steel bar mesh, so that a heat exchange tube structure attached to the steel bar skeleton is formed, and the arrangement and the fixation in the steel bar skeleton are facilitated.

Furthermore, a plurality of aluminum annular fins are fixedly welded on the U-shaped heat exchange tube or the inverted-U-shaped heat exchange tube, heated concrete can be effectively utilized, and the temperature of liquid in the heat exchange tube is accelerated.

Furthermore, the heat exchange tube comprises a plurality of U-shaped heat exchange tubes and a spiral heat exchange tube, inner ring heat exchange arms of the U-shaped heat exchange tubes form a cylindrical structure, concrete can be injected into the center to serve as a center support, and the spiral heat exchange tubes are respectively wound and fixed on outer ring heat exchange arms of the U-shaped heat exchange tubes and inner ring heat exchange arms of the U-shaped heat exchange tubes to form a stable cage-shaped structure, so that the contact area with heated concrete is greatly increased, and the fixing on the steel reinforcement framework is facilitated.

A manufacturing method of a high-heat-conductivity energy pile adopts high-heat-conductivity concrete to form a pile body, a liquid inlet gathering cavity and a liquid outlet gathering cavity are both higher than the upper surface of the high-heat-conductivity concrete, and the high-heat-conductivity concrete comprises the following components in parts by weight: 15-20 parts of cement, 30-35 parts of sand, 55-60 parts of broken stone, 10-11 parts of water, 0.03-0.04 part of water reducing agent, 1.5-4.5 parts of silicon carbide, and silicon carbide is added to form an effective silicon carbide-aggregate heat conduction network in the concrete, so that the heat conductivity coefficient of the concrete is improved, the heat exchange efficiency of the energy pile and rock soil is ensured, and the heat transfer coefficient of the energy pile is improved.

Furthermore, the mesh number of the silicon carbide is 12 meshes, and the cost performance is highest.

Drawings

Fig. 1 is a schematic structural view of a high thermal conductivity energy pile according to an embodiment of the present invention.

Fig. 2 is a schematic top view of the structure of fig. 1.

Fig. 3 is a schematic view of the sectional structure a-a of fig. 1.

Fig. 4 is a schematic structural diagram of a steel reinforcement cage according to an embodiment of the present invention.

Fig. 5 is another schematic top view of a high thermal conductivity energy pile.

Fig. 6 is a schematic diagram of another side view configuration of a high thermal conductivity energy pile.

FIG. 7 is a graph showing the trend of the concrete thermal conductivity according to the present invention.

Detailed Description

The following detailed description is made with reference to the accompanying drawings.

Example 1

A high-heat-conductivity energy pile comprises a concrete pile body (for convenience of clear expression, the concrete pile body is not shown in the drawing), a steel bar framework embedded in the concrete pile body and a heat exchange tube structure, wherein the steel bar framework is a cylindrical steel bar mesh 19, the heat exchange tube structure comprises a plurality of heat exchange tubes fixed on the inner side of the steel bar mesh 19 through binding wires, a first liquid inlet gathering cavity 5 connected with liquid inlets of the heat exchange tubes, a first liquid inlet tube 4 connected with the first liquid inlet gathering cavity, a first liquid outlet gathering cavity 6 connected with liquid outlets of the heat exchange tubes and a first liquid outlet tube 7 connected with the first liquid outlet gathering cavity, the heat exchange tubes comprise a plurality of U-shaped heat exchange tubes 9 and a spiral heat exchange tube 3, the U-shaped heat exchange tubes 9 are circumferentially distributed in the steel bar mesh, each U-shaped heat exchange tube is radially arranged along the steel bar mesh, and the spiral heat exchange tubes 3 are respectively wound on outer ring heat exchange arms 1 of the U-shaped heat exchange tubes and inner rings of the U- On the arm 2, the liquid inlet of each heat exchange tube is lower than the liquid outlet, and the first liquid inlet convergence cavity 5 connected with the liquid inlet of each heat exchange tube and the first liquid outlet convergence cavity 6 connected with the liquid outlet of each heat exchange tube are both annular boxes, and the inner diameter of the first liquid inlet convergence cavity is larger than the outer diameter of the first liquid outlet convergence cavity.

In the high-heat-conductivity energy pile of the embodiment, the heat exchange tube structure is fixed on the inner side of the steel bar framework, so that the heat exchange tube structure and the steel bar framework form a connected whole, the stability of the energy pile is enhanced, the plurality of heat exchange tubes form a general sub-general structure through the first liquid inlet convergence cavity and the first liquid outlet convergence cavity, liquid contacts the heated concrete with a larger area through the plurality of heat exchange tubes, heat is accumulated conveniently, and the temperature of the liquid is rapidly increased, the heat exchange tubes comprise a plurality of U-shaped heat exchange tubes and a spiral heat exchange tube, the inner ring heat exchange arms of the U-shaped heat exchange tubes form a cylindrical structure 8, the concrete can be injected into the center as a center support, the spiral heat exchange tubes are respectively wound and fixed on the outer ring heat exchange arms of the U-shaped heat exchange tubes and the inner ring heat exchange arms of the U-shaped heat exchange, and the fixation on the steel reinforcement framework is also convenient.

Example 2

As shown in fig. 5-6, different from the above embodiments, the heat exchange tube is a U-shaped heat exchange tube or an inverted-n-shaped heat exchange tube, in this embodiment, an inverted-n-shaped heat exchange tube is adopted, the inverted-n-shaped heat exchange tube includes two heat exchange arms, a bottom tube 17 connected to bottoms of the heat exchange arms, and connecting tubes 18 respectively connected to two ends of tops of the heat exchange arms, each inverted-n-shaped heat exchange tube is disposed in parallel in a steel bar mesh, a distance between the two heat exchange arms of each inverted-n-shaped heat exchange tube gradually decreases from a middle portion to two sides of the steel bar mesh, a liquid inlet of each inverted-n-shaped heat exchange tube is communicated with a second liquid inlet collecting chamber 12, a liquid outlet of each inverted-n-shaped heat exchange tube is communicated with a second liquid outlet collecting chamber 15, the second liquid outlet collecting chamber 15 is connected with a second liquid outlet tube 16, the second liquid inlet collecting, the present embodiment employs an arc-shaped box.

The high heat conduction energy stake of this embodiment, each U-shaped heat exchange tube or the shape of falling several characters heat exchange tube parallel arrangement in the reinforcing bar net, and the interval between two heat transfer arms of each U-shaped heat exchange tube or the shape of falling several characters heat exchange tube diminishes from the middle part to both sides of reinforcing bar net gradually, forms a laminating steel reinforcement framework's heat exchange tube structure, and the convenience is arranged and is fixed in steel reinforcement framework.

In other embodiments, different from the above embodiments, a plurality of aluminum ring fins are welded on each heat exchange tube, the aluminum ring fins are not shown in fig. 1-5 for cleaning expression, and the aluminum ring fins 14 are arranged on only one of the heat exchange tubes in fig. 6, so that the heat in the heated concrete can be more effectively utilized by the aluminum ring fins 14, and the temperature rise of the liquid in the heat exchange tubes can be accelerated.

Example 3

A method for manufacturing a high thermal conductivity energy pile, as shown in fig. 7, includes the following steps: step 1, fixing the heat exchange tube in the embodiment on the inner side of a cylindrical mesh reinforcement, inserting the mesh reinforcement and the heat exchange tube into a pile hole through a hoisting machine, wherein gaps are reserved between the bottoms of the mesh reinforcement and the heat exchange tube and the bottom of the pile hole as well as between the circumferential direction of the mesh reinforcement and the side wall of the pile hole;

Step 2, adding high heat conduction concrete into the pile hole to form a pile body, wherein the liquid inlet gathering cavity and the liquid outlet gathering cavity are both higher than the upper surface of the high heat conduction concrete, and then performing junction maintenance, wherein the high heat conduction concrete comprises the following components in parts by weight: 15-20 parts of cement, 30-35 parts of sand, 55-60 parts of broken stone, 10-11 parts of water, 0.03-0.04 part of water reducing agent and 1.5-4.5 parts of silicon carbide.

In this embodiment, the endpoint values and any intermediate values within the ranges of each component may be selected as desired,the various specific mixing ratios are not listed here. It should be noted that the mesh number of the silicon carbide is 11-125, and the mesh number of the silicon carbide is 12 in this embodiment. The sand is river sand, the grading is medium sand, the fineness modulus of the sand is 2.3-3.0, and the bulk density is 1480-1560 kg/m³。

The broken stone is limestone or granite broken stone and is formed by grading broken stones with the particle sizes of 5-10 mm, 10-20 mm and 20-30 mm according to the mass ratio of 3:4:3 or 2:5: 3.

The manufacturing method of the high-thermal-conductivity energy pile of the embodiment adopts high-thermal-conductivity concrete to form the pile body, wherein the high-thermal-conductivity concrete comprises the following components in parts by weight: the concrete heat conduction system is characterized in that cement, sand, broken stone, water, a water reducing agent and silicon carbide are added, an effective silicon carbide-aggregate heat conduction network is formed inside the concrete, and the heat conduction coefficient of the concrete is improved, so that the heat exchange efficiency of the energy pile and rock soil is ensured, and the heat transfer coefficient of the energy pile is improved.

Experiments show that when the mesh number of the silicon carbide is changed, the heat conductivity coefficient is not a linear change rule, and through numerous experiments, technicians find that the heat conductivity coefficient is better than 46 meshes when the mesh number of the silicon carbide is 12 meshes, the effect of 120 meshes can be achieved even when the volume fraction is replaced by 10%, and the cost performance is highest.

And (3) testing:

in order to analyze the influence of the mixing amount of the silicon carbide on the heat conductivity coefficient and the mechanical property of the concrete, 5 percent, 10 percent and 15 percent of different granular silicon carbide are respectively selected for proportioning, and the admixture is a water reducing agent, and the specific proportion is shown in Table 1

Table 1: the concrete proportion of the silicon carbide high-substitution volume fraction is used for carrying out a compressive strength test and a flexural strength test on a high-heat-conductivity concrete test piece doped with silicon carbide (SiC). The results of the compressive strength tests of the concrete under different purposes and different amounts of silicon carbide are shown in tables 2 and 3.

TABLE 2 test results of compressive strength of high thermal conductivity concrete doped with silicon carbide (SiC)

TABLE 3 test results of flexural strength of high thermal conductivity concrete doped with silicon carbide (SiC)

It can be seen that the larger the mesh number of the doped silicon carbide particles is, the more obvious the strength improvement of the concrete is. In addition, when the number of the silicon carbide meshes is smaller (12 meshes), the concrete strength is reduced to a certain extent along with the increase of the doping amount of the silicon carbide; when the silicon carbide mesh number is larger, the concrete strength is gradually increased along with the increase of the silicon carbide doping amount. The larger the number of the particles, the better the breaking strength.

As shown in fig. 7, the thermal conductivity of the concrete increases with the silicon carbide content, for example, when the silicon carbide content is increased from 0% to 15%, the thermal conductivity of the concrete increases by about 150%, which is mainly due to the high thermal coefficient of silicon carbide.

In conclusion, a certain amount of silicon carbide (SiC) heat conduction reinforcing materials are added into the concrete, so that the heat conductivity coefficient of the concrete can be greatly improved, and the compressive strength of the concrete can be improved in a small range when the mesh number is larger.

The above is a preferred embodiment of the present invention, but it should be understood that the above detailed description should not be construed as limiting the spirit and scope of the present invention, and obvious modifications or substitutions made by those skilled in the art based on the above embodiment still fall into the protection scope of the present invention.

Claims

1. The high-heat-conductivity energy pile is characterized by comprising a concrete pile body, a steel bar framework and a heat exchange tube structure, wherein the steel bar framework is embedded in the concrete pile body, the steel bar framework is a cylindrical steel bar mesh, and the heat exchange tube structure comprises a plurality of heat exchange tubes fixedly arranged on the inner side of the steel bar mesh, a liquid inlet gathering cavity connected with liquid inlets of the heat exchange tubes, a liquid inlet tube connected with the liquid inlet gathering cavity, a liquid outlet gathering cavity connected with liquid outlets of the heat exchange tubes and a liquid outlet tube connected with the liquid outlet gathering cavity.

2. A high thermal conductivity energy pile according to claim 1, wherein: the heat exchange tube is U-shaped heat exchange tube or the heat exchange tube of the shape of falling several characters, each U-shaped heat exchange tube or the heat exchange tube of the shape of falling several characters parallel arrangement in reinforcing bar net, and the interval between two heat transfer arms of each U-shaped heat exchange tube or the heat exchange tube of the shape of falling several characters diminishes from the middle part to both sides of reinforcing bar net gradually, the inlet and the feed liquor of each U-shaped heat exchange tube or the heat exchange tube of the shape of falling several characters assemble the chamber intercommunication, the liquid outlet and the play liquid of each U-shaped heat exchange tube or the heat exchange tube of the shape of falling several characters assemble the chamber.

3. A high thermal conductivity energy pile according to claim 2, wherein: and a plurality of aluminum annular fins are fixedly welded on the U-shaped heat exchange tube or the inverted-U-shaped heat exchange tube.

4. A high thermal conductivity energy pile according to claim 1, wherein: the heat exchange tube includes a plurality of U-shaped heat exchange tubes and a spiral heat exchange tube, a plurality of U-shaped heat exchange tubes are at reinforcing bar net circumference distribution and every U-shaped heat exchange tube all radially sets up along the reinforcing bar net, the spiral heat exchange tube is around establishing respectively and fixing on the outer lane heat exchange arm of each U-shaped heat exchange tube and the inner circle heat exchange arm of each U-shaped heat exchange tube, the inlet of each heat exchange tube is less than the liquid outlet, the feed liquor of being connected with each heat exchange tube inlet assembles the chamber and assembles the chamber with the play liquid that each heat exchange tube liquid outlet is connected and be annular box, the internal diameter that the feed liquor assembles.

5. A high thermal conductivity energy pile according to claim 4, wherein: and a plurality of aluminum annular fins are fixedly welded on the U-shaped heat exchange tube and the spiral heat exchange tube.

6. A manufacturing method of a high-heat-conductivity energy pile is characterized by comprising the following steps: step 1, fixing the heat exchange tube according to any one of claims 1 to 5 on the inner side of a cylindrical mesh reinforcement, inserting the mesh reinforcement and the heat exchange tube into a pile hole together by a hoisting machine, wherein gaps are reserved between the bottom of the mesh reinforcement and the heat exchange tube and the bottom of the pile hole as well as between the circumference of the mesh reinforcement and the side wall of the pile hole; step 2, adding high thermal conductivity concrete into the pile hole to form a pile body, wherein the liquid inlet gathering cavity and the liquid outlet gathering cavity are both higher than the upper surface of the high thermal conductivity concrete, and then curing, wherein the high thermal conductivity concrete comprises the following components in parts by weight: 15-20 parts of cement, 30-35 parts of sand, 55-60 parts of broken stone, 10-11 parts of water, 0.03-0.04 part of water reducing agent and 1.5-4.5 parts of silicon carbide.

7. The method for manufacturing a high thermal conductivity energy pile according to claim 6, wherein: the mesh number of the silicon carbide is 11-125 meshes.

8. The method for manufacturing a high thermal conductivity energy pile according to claim 7, wherein: the mesh number of the silicon carbide is 12 meshes.

9. The method for manufacturing a high thermal conductivity energy pile according to claim 6, wherein: the sand is river sand, the grading is medium sand, the fineness modulus of the sand is 2.3-3.0, and the bulk density is 1480-1560 kg/m³。

10. The method for manufacturing a high thermal conductivity energy pile according to claim 6, wherein: the broken stone is limestone or granite broken stone and is formed by grading broken stones with the particle sizes of 5-10 mm, 10-20 mm and 20-30 mm according to the mass ratio of 3:4:3 or 2:5: 3.