阅读说明：本技术 含辐射隔热膜的中深层套管式地热换热器装置 (Middle-deep sleeve type geothermal heat exchanger device containing radiation heat insulation film ) 是由 于明志 张方方 毛煜东 崔萍 张文科 于 2020-05-28 设计创作，主要内容包括：本发明公开了一种含辐射隔热膜的中深层套管式地热换热器装置,由多节套管式地热换热器连接而成。单节套管式地热换热器包括内管和外管,内管管壁中有真空绝热夹层,真空绝热夹层内设有一层与内管同轴的环形辐射隔热膜。相邻两节换热器的内、外管均采用焊接连接。辐射隔热膜设置于真空绝热夹层中间位置。本发明通过在中深层套管式地热换热器内管管壁中增设含辐射隔热膜的真空绝热夹层,有效降低内外流道间管壁中夹层两壁面间的热辐射能力,减小套管内外流道间“热短路”,提高中深层套管式地热换热器的取热效率。(The invention discloses a middle-deep sleeve type geothermal heat exchanger device containing a radiation heat-insulating film, which is formed by connecting a multi-section sleeve type geothermal heat exchanger. The single-section sleeve type geothermal heat exchanger comprises an inner pipe and an outer pipe, wherein a vacuum heat insulation interlayer is arranged in the pipe wall of the inner pipe, and an annular radiation heat insulation film which is coaxial with the inner pipe is arranged in the vacuum heat insulation interlayer. The inner pipe and the outer pipe of two adjacent sections of heat exchangers are connected by welding. The radiation heat insulation film is arranged in the middle of the vacuum heat insulation interlayer. According to the invention, the vacuum heat insulation interlayer containing the radiation heat insulation film is additionally arranged in the pipe wall of the inner pipe of the middle-deep sleeve type geothermal heat exchanger, so that the heat radiation capability between two wall surfaces of the interlayer in the pipe wall between the inner runner and the outer runner is effectively reduced, the thermal short circuit between the inner runner and the outer runner of the sleeve is reduced, and the heat taking efficiency of the middle-deep sleeve type geothermal heat exchanger is improved.)

1. A middle-deep sleeve type geothermal heat exchanger device containing a radiation heat insulation film is formed by connecting a plurality of sleeve type geothermal heat exchangers and is characterized in that a single-section sleeve type geothermal heat exchanger comprises an inner pipe and an outer pipe, a vacuum heat insulation interlayer is arranged in the wall of the inner pipe, the vacuum heat insulation interlayer is a hollow cavity, a layer of annular radiation heat insulation film coaxial with the inner pipe is arranged in the vacuum heat insulation interlayer, and the inner pipe and the outer pipe of two adjacent sections of heat exchangers are connected in a welding mode.

2. The geothermal heat exchanger device according to claim 1, wherein the top end of the inner wall of the inner pipe is 50 to 100mm longer than the top end of the vacuum insulation jacket, and the bottom end of the inner wall of the inner pipe is 50 to 100mm longer than the bottom end of the vacuum insulation jacket.

3. The radiant heat insulating film-containing geothermal heat exchanger device of claim 1, wherein the inner tube and the outer tube of the heat exchanger are seamless galvanized steel tubes, and wherein the inner tube has a pressure of higher than 15 MPa.

4. The geothermal heat exchanger device of claim 1, wherein the vacuum insulation layer has a thickness of less than 10mm and the vacuum level of the vacuum insulation layer is less than 10 Pa.

5. The device as claimed in claim 1, wherein the radiant heat insulating film is made of aluminum foil, the thickness of the aluminum foil is 0.5mm or less, the normal emissivity is less than 0.05 at normal temperature, and the reflectivity is greater than 0.9.

6. The geothermal heat exchanger device according to claim 1, wherein the radiant heat insulating film is provided at a position intermediate the vacuum heat insulating interlayers and half the thickness of the vacuum heat insulating interlayers from the outer wall of the inner pipe.

7. The deep-pipe geothermal heat exchanger device according to claim 1 or 5, wherein the radiant heat insulating film is provided in a hanging manner, and there are two types of hanging manners: the top end of the first radiation heat-insulation film is flush with the top end in the interlayer, and the bottom end of the first radiation heat-insulation film is positioned 100mm above the bottom end in the interlayer; the top end of the second radiation heat-insulation film is flush with the top end in the interlayer, and the bottom end of the second radiation heat-insulation film is flush with the bottom end in the interlayer.

8. The geothermal heat exchanger device of claim 7, wherein the radiant heat insulating film is formed in a first form by hanging, and a platform having a thickness of 5mm is provided at a position 10mm downward from the top end of the vacuum heat insulating interlayer, and the radial length of the platform is half the thickness of the vacuum heat insulating interlayer; the radiation heat-insulation film with the annular gasket is tightly attached to the edge of the bearing platform, and the lower side of the gasket is tightly attached to the upper surface of the bearing platform and is placed on the bearing platform; the width of the annular gasket is half of the thickness of the vacuum heat insulation interlayer, and the thickness of the annular gasket is 5 mm.

9. The geothermal heat exchanger device of claim 7, wherein the radiant heat insulating film is formed in a second form by hanging, and a platform having a thickness of 5mm is provided at a position 10mm downward from the top end of the vacuum heat insulating interlayer, and the radial length of the platform is half the thickness of the vacuum heat insulating interlayer; the radiation heat-insulation film with the annular gasket is tightly attached to the edge of the bearing platform, and the lower side of the gasket is tightly attached to the upper surface of the bearing platform and is placed on the bearing platform; the width of the annular gasket is half of the thickness of the vacuum heat insulation interlayer, the thickness of the annular gasket is 5mm, and the length of the radiation heat insulation film is the same as that of the vacuum heat insulation interlayer.

10. The geothermal heat exchanger device of claim 9, wherein the radiant heat insulating film is provided with a plurality of ventilation holes, and the total area of the ventilation holes is larger than or equal to the annular area of the top of the vacuum heat insulating interlayer, so as to satisfy the circulation requirement of vacuum pumping.

Technical Field

The invention relates to a sleeve type intermediate-deep geothermal heat exchanger technology, in particular to an intermediate-deep sleeve type geothermal heat exchanger device containing a radiation heat insulation film.

Background

In recent years, due to the needs of energy development, environmental management and improvement of civil life, the geothermal energy heating technology is facing a critical development opportunity, and the application proportion of the geothermal energy heating technology in the heating industry is higher and higher. The ground source heat pump of the buried pipe is the most widely applied technology in the geothermal heating. According to different buried pipe depths, the buried pipe ground source heat pump can be divided into a shallow buried pipe ground source heat pump and a middle-deep buried pipe ground source heat pump. The buried depth of the underground heat exchanger of the ground source heat pump can reach 1500-3000m, the heat taking temperature is high, the heat taking quantity is large, the occupied area is small, the problems that the shallow buried ground source heat pump is small in heat taking quantity and large in occupied area, the application is limited in severe cold and cold regions in the north and the land shortage region and the like can be effectively solved, and a new path is opened up for popularization and application of the middle-deep geothermal energy in the northern region of China.

The pipe embedding mode of the intermediate-deep geothermal heat exchanger mainly comprises a sleeve pipe mode and a U-shaped pipe mode. The most common of the intermediate geothermal heat exchangers is currently the double pipe geothermal heat exchanger. Because the temperatures of circulating liquids in the inner pipe and the outer pipe of the double-pipe geothermal heat exchanger are different, if no measures are taken, heat is easily transferred from a flow channel with high temperature to a flow channel with low temperature, so that thermal short circuit is caused, and the heat taking capacity of the double-pipe geothermal heat exchanger is influenced. In order to reduce the loss caused by 'thermal short circuit' between the inner tube and the outer tube of the sleeve-type geothermal heat exchanger, two methods are mainly adopted in engineering: firstly, the pipe material of the inner pipe of the sleeve needs to be made of a material with relatively low heat conductivity coefficient. Although the method is simple and easy, the heat conduction resistance of the pipe wall between the inner flow passage and the outer flow passage is still not large enough; and secondly, arranging an interlayer on the inner wall of the sleeve, and vacuumizing the interlayer to isolate heat exchange between fluids in the inner pipe and the outer pipe. Although this method can effectively reduce the heat transfer between the fluids of the inner and outer tubes by reducing the gas-phase heat conduction in the interlayer, there is also significant radiative heat transfer between the two walls in the interlayer. Research shows that when the absolute pressure of the vacuum interlayer is reduced to 2KPa or lower, the heat exchange of the vacuum interlayer is mainly radiation heat exchange. Therefore, for a mid-deep tube-in-tube geothermal heat exchanger with an interlayer, further reduction of the "thermal short circuit" losses inside the tube must be considered to reduce the radiant heat losses.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a middle-deep sleeve type geothermal heat exchanger device containing a radiation heat insulation film, which reduces the thermal short circuit between the inner and outer flow channels of the sleeve and improves the heat extraction efficiency of the middle-deep sleeve type geothermal heat exchanger by reducing the heat radiation capability between two wall surfaces of an interlayer in the tube wall between the inner and outer flow channels.

In order to achieve the purpose, the invention adopts the following technical scheme:

the medium-deep sleeve type geothermal heat exchanger device containing the radiation heat-insulating film is formed by combining a plurality of sleeve type geothermal heat exchangers with the lengths of 9-12m according to the actual engineering requirements, wherein the single-section sleeve type geothermal heat exchanger comprises an inner pipe and an outer pipe, the wall of the inner pipe is provided with a vacuum heat-insulating interlayer containing the radiation heat-insulating film, and the radiation heat-insulating film is annular and coaxial with the inner pipe. The length of the single-section heat exchanger is 9-12m, so that the process difficulty is reduced during construction, and long-distance transportation is facilitated.

The inner pipe and the outer pipe are both made of high-pressure-resistant, high-temperature-resistant and corrosion-resistant seamless galvanized steel pipes, wherein the vacuum heat-insulating interlayer in the pipe wall of the inner pipe is a hollow cavity, one side of two wall surfaces of the vacuum heat-insulating interlayer is basically free of pressure, the hydrostatic pressure at one side is very large, the pressure-bearing requirement of the wall surface with large pressure difference at two sides is high, therefore, the inner wall and the outer wall of the inner pipe bear pressure, and the pressure-bearing requirement of steel materials of the inner. Because both sides of the outer pipe are provided with pressure, the pressure bearing requirement of the steel pipe can be properly reduced according to the requirement of the inner pipe.

The vacuum heat insulation interlayer in the inner pipe wall is an annular cavity in the inner pipe wall, and the interlayer is subjected to vacuum pumping treatment. The thickness of the interlayer is less than 10mm in consideration of the vacuumizing circulation space and the operation requirement. The axial length of the vacuum heat insulation interlayer is equal to that of the outer pipe. In order to maintain the heat insulating effect, it is required to maintain a degree of vacuum of less than 10Pa in the vacuum heat insulating interlayer.

And a layer of radiation heat-insulating film and a getter are arranged in the vacuum heat-insulating interlayer.

The radiation heat insulation film is low in emissivity and high in reflectivity. The radiation heat insulation film and the inner pipe are coaxially arranged.

The radiation heat insulation film is made of aluminum foil, and the aluminum foil is low in emissivity, high in reflectivity, long in gloss retention time and low in cost. The thickness of the aluminum foil is not more than 0.5mm, the normal emissivity is less than 0.05 under the normal temperature condition, the reflectivity can reach more than 0.9, and the emissivity and the reflectivity of the aluminum have little change from the normal temperature to 320 ℃. The thickness of the vacuum heat insulation interlayer between the radiation heat insulation film and the outer wall surface of the inner pipe is half of that of the vacuum heat insulation interlayer, so that the heat radiation exchange capacity of the two wall surfaces of the interlayer is favorably reduced, and the thermal short circuit between the flow channels of the inner pipe and the outer pipe is inhibited. When the top end of the radiation heat-insulating film is flush with the top end of the interior of the interlayer, a certain space is required to be reserved at the bottom end of the radiation heat-insulating film for the space requirement of vacuum pumping and the action requirement of a getter; when both ends of the radiation heat-insulation film are flush with the upper end and the lower end in the interlayer, the radiation heat-insulation film is required to be provided with vent holes.

The radiation heat insulation film adopts hoisting setting, and has two hoisting forms: the top end of the first radiation heat-insulation film is flush with the top end in the interlayer, and the bottom end of the first radiation heat-insulation film is positioned about 100mm above the bottom end in the interlayer; the top end of the second radiation heat-insulation film is flush with the top end in the interlayer, and the bottom end of the second radiation heat-insulation film is flush with the bottom end in the interlayer.

The first hoisting form of the radiation heat insulation film in the vacuum heat insulation interlayer is characterized in that a bearing platform with the thickness of 5mm is arranged at a position 10mm downwards from the top end of the vacuum heat insulation interlayer, and the radial length of the bearing platform is half of the thickness of the vacuum heat insulation interlayer. The radiation heat insulation film with the annular gasket is tightly attached to the edge of the bearing platform, and the lower side of the gasket is tightly attached to the upper surface of the bearing platform and placed on the bearing platform, so that the radiation heat insulation film can be vertically placed in the vacuum heat insulation interlayer. The width of the annular gasket is half of the thickness of the vacuum heat insulation interlayer, and the thickness of the annular gasket is 5mm, so that the radiation heat insulation film is suspended in the middle of the vacuum heat insulation interlayer and is fixed. The length of the radiation heat insulation film is 100mm less than that of the vacuum heat insulation interlayer.

The second hoisting mode of the radiation heat insulation film in the vacuum heat insulation interlayer is characterized in that a bearing platform with the thickness of 5mm is arranged at a position 10mm below the top end of the vacuum heat insulation interlayer, and the radial length of the bearing platform is half of the thickness of the vacuum heat insulation interlayer. The radiation heat insulation film with the annular gasket is tightly attached to the edge of the bearing platform, and the lower side of the gasket is tightly attached to the upper surface of the bearing platform and placed on the bearing platform, so that the radiation heat insulation film can be vertically placed in the vacuum heat insulation interlayer. The width of the annular gasket is half of the thickness of the vacuum heat insulation interlayer, and the thickness of the annular gasket is 5mm, so that the radiation heat insulation film is suspended in the middle of the vacuum heat insulation interlayer and is fixed. The length of the radiation heat insulation film is the same as that of the vacuum heat insulation interlayer. The axial lower end of the radiation heat insulation film is upwards provided with at least 20 vent holes which are axially equidistant and are symmetrical front and back, the diameter of each vent hole is 20mm, and the axial distance is 50 mm. The total area of the vent holes is larger than or equal to the annular area of the upper part of the vacuum heat insulation interlayer, so that the flow requirement of vacuumizing can be met.

The top end and the bottom end of the inner wall of the inner pipe of the single-section double-pipe geothermal heat exchanger are slightly longer than the top end and the bottom end of the interlayer for welding connection, and the length is about 50-100mm under the general condition.

The single-section sleeve type geothermal heat exchanger considers the vacuum degree of the protective interlayer and reduces the difficulty of construction technology, the vacuum heat insulation interlayer on the inner pipe wall is finished by adopting a factory processing mode, and field installation only needs to finish connection and tube discharging of the outer pipe and the inner pipe respectively. Wherein the outer pipe and the inner pipe are connected by adopting a welding process.

Compared with the prior art, the invention has the advantages that:

1) the radiant heat insulation film is additionally arranged in the vacuum interlayer of the inner pipe wall of the middle-deep sleeve type geothermal heat exchanger, and the surface of the selected aluminum foil heat insulation film has very low emissivity and high reflectivity, so that the heat radiation capability between the two wall surfaces of the pipe wall interlayer between the inner runner and the outer runner can be obviously reduced, the thermal short circuit between the inner runner and the outer runner of the sleeve is reduced, and the heat taking efficiency of the middle-deep sleeve type geothermal heat exchanger is improved.

2) The intermediate-deep sleeve type geothermal heat exchanger containing the radiation heat-insulating film is beneficial to ensuring stable and reliable product performance and effectively shortening the construction period.

3) The medium-deep sleeve type geothermal heat exchanger containing the radiation heat insulation film has the advantages of simple and feasible field installation and connection procedures, small construction technical difficulty and high reliability.

Drawings

FIG. 1 is a schematic cross-sectional view of examples 1 and 2;

FIG. 2 is a schematic side sectional view of example 1;

FIG. 3 is a schematic side sectional view of example 2;

FIG. 4 is a schematic view showing the perforation of the radiation shielding film in example 2;

FIG. 5 is a graph comparing reduced radiant heat loss for the examples compared to the prior art;

wherein, 1, the inner tube; 2. an outer tube; 3. a vacuum heat insulation interlayer; 4. a radiation heat insulating film; 5. a getter; 6. a bearing platform; 7. an annular gasket; 8. and (4) a vent hole.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The structures, proportions, sizes, and other dimensions shown in the drawings and described in the specification are for understanding and reading the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined in the claims, and are not essential to the art, and any structural modifications, changes in proportions, or adjustments in size, which do not affect the efficacy or achievement of the intended purposes of the present disclosure, are intended to be included within the scope of the present disclosure. In addition, the terms "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not to be construed as a scope of the present invention.