A preparation method of a self-sealing spiral buried pipe heat exchanger and the spiral buried pipe heat exchanger

Abstract

The application discloses a preparation method of a self-packaging spiral buried pipe heat exchanger and the spiral buried pipe heat exchanger, and the method comprises the following steps: mixing and stirring a shape-fixed phase change material and a heat-conducting silicone grease to form a slurry material; feeding PE material into a first feeding hopper, conveying the PE material to a shearing machine to shear the PE material into small granular PE material, conveying the small granular PE material to a heating mechanism to melt the small granular PE material into liquid PE material, and then conveying the liquid PE material to a first forming mold to extrude the liquid PE material into a tubular PE pipe; conveying the tubular PE pipe which has not been shaped to a second forming mold, feeding the slurry material into a second feeding hopper at the same time, and making the slurry material adhere to the surface of the tubular PE pipe; then conveying the tubular PE pipe to a cooling mechanism to cool and shape the tubular PE pipe; conveying the shaped tubular PE pipe to a film sealing machine to seal a film on the tubular PE pipe, so as to obtain a self-packaging heat exchanger straight pipe; and further processing the self-packaging heat exchanger straight pipe to form a heat exchanger straight pipe with a required length and spiral parameters. The application can improve the heat exchange performance of the spiral buried pipe heat exchanger while ensuring economy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shallow geothermal energy utilization, and particularly relates to a preparation method of a self-packaging spiral buried pipe heat exchanger and the spiral buried pipe heat exchanger. BACKGROUND

[0002] Geothermal energy is a clean energy, and its resource quantity is large, and its application scenarios are very wide. The ground source heat pump is the most common form of geothermal energy application. The ground source heat pump takes underground water, underground soil or rock body as a cold and heat source, and then utilizes the heat pump unit to realize the transfer of low-level heat energy to high-level heat energy through a small amount of high-level electric energy input. The ground source heat pump can both supply cold and heat, and is a high-efficiency, environmentally-friendly and energy-saving air conditioning utilization form. The ground source heat pump system includes an above-ground heat exchanger part and an underground heat exchanger part, and the overall energy efficiency ratio of the ground source heat pump is mainly determined by the underground heat exchanger part. The underground heat exchanger heat exchange process is the heat exchange between the heat exchange medium in the pipe and the underground soil outside the pipe, and the heat exchange medium in the pipe is generally water. Since the water in the pipe has a convection heat exchange process, the heat exchange effect is strong, and the soil outside the pipe is a pure conduction process, and the heat transfer effect is very poor. Therefore, the underground buried pipe filler has a significant influence on the performance of the overall ground source heat pump system. The existing backfill materials mainly include original slurry backfill and bentonite-based backfill materials, and the original slurry backfill and the bentonite-based backfill are prone to generate a large contact thermal resistance, thereby affecting the efficiency of the heat exchanger. Moreover, if the conventional buried pipe drilling is large, and if the backfill material is used for backfilling, the economy is poor. SUMMARY

[0003] In view of the problems in the prior art, the present application aims to provide a preparation method of a self-packaging spiral buried pipe heat exchanger and the spiral buried pipe heat exchanger, which can improve the heat exchange performance of the spiral buried pipe heat exchanger while ensuring the economy.

[0004] In order to achieve the above-mentioned purpose, the present application provides a preparation method of a self-packaging spiral buried pipe heat exchanger, which comprises a spiral buried pipe heat exchanger preparation device, and the spiral buried pipe heat exchanger preparation device comprises first feeding hopper, shearing machine, heating mechanism, first forming die, second forming die, cooling mechanism and film sealing machine which are connected in sequence, and a second feeding hopper is further connected to the feeding port of the second forming die. The method comprises the following steps:

[0005] S1, preparing a shaped phase change material;

[0006] S2, mixing and stirring the shaped phase change material and the heat-conducting silicone grease to form a slurry material;

[0007] S3, the PE material is put into the first feeding hopper, the PE material is first passed to the shearing machine, the shearing machine is cut into small granular PE material, and then the small granular PE material is passed to the heating mechanism, the heating mechanism is melted into a liquid state, then the liquid state PE material is passed to the first forming mold, and the first forming mold is extruded into a tubular shape;

[0008] S4, the PE pipe which has not yet completed the shaping is passed to the second forming mold, and the slurry material is put into the second feeding hopper, so that the slurry material is attached to the surface of the PE pipe;

[0009] S5, the PE pipe with the completed attachment is passed to the cooling mechanism for temperature reduction and shaping;

[0010] S6, the shaped PE pipe is passed to the film sealing machine, the PE pipe after the attachment is completely wrapped with the PE film, and a self-sealing heat exchanger straight pipe is obtained;

[0011] S7, the prepared self-sealing heat exchanger straight pipe is further processed to form a required length and spiral parameter.

[0012] In the above scheme: the spiral buried pipe heat exchanger is provided with a vacuum layer outside the return water pipe, so as to achieve the purpose of heat preservation of the return water pipe.

[0013] In the above scheme: the shaped phase change material is prepared by using expanded graphite to absorb paraffin wax, wherein the mass ratio of expanded graphite to paraffin wax is 1:10, and the preparation method is vacuum impregnation.

[0014] In the above scheme: the specific steps for preparing the shaped phase change material are:

[0015] 1) the expanded graphite is placed in a container and placed in a 120℃ environment for 12 hours;

[0016] 2) the expanded graphite is added with paraffin wax in a mass ratio of 1:10;

[0017] 3) the container containing the paraffin wax and the expanded graphite is placed in a vacuum drying box for vacuum adsorption, the vacuum degree is 0.08MPa, the temperature is 50℃, and the whole process needs to last for 10 hours, wherein the container is taken out and stirred once every 2 hours.

[0018] In the above scheme: the self-sealing heat exchanger straight pipe is processed into a required spiral parameter by using a pipe bending machine.

[0019] The application also provides a spiral buried pipe heat exchanger prepared by the above preparation method of the self-sealing spiral buried pipe heat exchanger.

[0020] The application has the following beneficial effects:

[0021] The new mixed backfill material is mixed and stirred with the heat-conducting silicone grease to form a slurry material, the existing PE pipe production uses a mature extrusion process, the slurry material is added in the preparation process, the slurry material is attached to the surface of the PE pipe by taking advantage of the state of the PE pipe that has not yet been shaped, and then the PE pipe is packaged by using a film sealing machine to form an installable spiral buried pipe heat exchange pipe; therefore, the spiral buried pipe heat exchange pipe can be constructed in advance in a processing workshop, and then the finished product is transported to the site and directly buried in the corresponding well to improve the construction efficiency of the spiral buried pipe heat exchange pipe.

[0022] Compared with the conventional backfill material, the shaped phase change material has the advantages of large thermal conductivity, large specific heat capacity, phase change latent heat storage and the like; under the same ground source heat pump buried pipe inlet water temperature, due to the high thermal conductivity and high heat storage material in the buried pipe, the heat exchanged between the fluid and the backfill material can be stored, the fluid and the surrounding backfill material heat exchange temperature difference is increased, and the purpose of enhancing the heat exchange effect of the spiral buried pipe heat exchanger is achieved, and under the condition of reasonable operation, the heat exchange efficiency of the spiral buried pipe heat exchanger can be maintained for a long time;

[0023] The conventional buried pipe drilling is large, and if the shaped phase change material is used for backfilling, the economy is poor, since the buried pipe heat exchanger exchanges heat in the direction of the pipe diameter, and there is a thermal action radius in the heat exchange period, therefore, the backfill material is attached to the PE pipe in the form of a casing pipe, which can greatly improve the economic benefit and reduce the waste of the filler;

[0024] In actual use, spiral buried pipe heat exchangers of different lengths can be prepared to meet the needs of drillings of different depths. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic view of a spiral buried pipe heat exchanger preparation device in the application. DETAILED DESCRIPTION

[0026] As shown in Figure 1 A preparation method of a self-packaging spiral buried pipe heat exchanger, comprising a spiral buried pipe heat exchanger preparation device, the spiral buried pipe heat exchanger preparation device comprises first feeding hopper 1, shearing machine 2, heating mechanism 3, first forming die 4, second forming die 5, cooling mechanism 6 and film sealing machine 7 connected in sequence, and second feeding hopper 8 is further connected at the inlet of the second forming die 5, and the method specifically comprises the following steps:

[0027] Preparation of shaped phase change material.

[0028] Mixing and stirring the shaped phase change material with the heat-conducting silicone grease to form a slurry material.

[0029] The PE material is put into the first feeding hopper 1, and then is sent to the shearing machine 2 to be sheared into small particles, and then is sent to the heating mechanism 3 to be melted into a liquid state, and then is sent to the first forming mold 4 to be extruded into a tubular shape.

[0030] The PE pipe which has not yet completed shaping is sent to the second forming mold 5, and at the same time, the slurry material is put into the second feeding hopper 8 so that the slurry material adheres to the surface of the PE pipe.

[0031] The PE pipe with completed adhesion is sent to the cooling mechanism 6 for cooling and shaping.

[0032] The shaped PE pipe is sent to the film sealing machine 7 to be completely wrapped with the PE film to obtain the self-sealing heat exchanger straight pipe.

[0033] The prepared self-sealing heat exchanger straight pipe is further processed to form the required length and spiral parameters.

[0034] Preferably, a vacuum layer is arranged outside the return water pipe of the spiral pipe heat exchanger to achieve the heat preservation purpose of the return water pipe.

[0035] Preferably, the shaped phase change material is prepared by using expanded graphite to absorb paraffin wax, and the mass ratio of the expanded graphite to the paraffin wax is 1:10, and the preparation method is vacuum impregnation.

[0036] Preferably, the specific steps for preparing the shaped phase change material are as follows: the expanded graphite is placed in a container and is left to stand in an environment of 120℃ for 12 hours; the paraffin wax is added to the expanded graphite with a mass ratio of 1:10; the container with the paraffin wax and the expanded graphite is placed in a vacuum drying box for vacuum adsorption, the vacuum degree is 0.08MPa, and the temperature is 50℃, and the whole process needs to last for 10 hours, and the container is taken out and stirred once every 2 hours.

[0037] Preferably, the self-sealing heat exchanger straight pipe is processed into the required spiral parameters by using a pipe bending machine.

[0038] A spiral pipe heat exchanger is prepared by using the above self-sealing spiral pipe heat exchanger preparation method, the surface of the spiral pipe heat exchanger is adhered with the shaped phase change material, and is sealed by the PE film.

Claims

1. A method for preparing a self-encapsulated spiral embedded tube heat exchanger, comprising spiral embedded tube heat exchanger preparation equipment, characterized in that: The spiral embedded tube heat exchanger manufacturing equipment includes a first feeding hopper (1), a shearing machine (2), a heating mechanism (3), a first forming mold (4), a second forming mold (5), a cooling mechanism (6), and a sealing machine (7) connected in sequence. A second feeding hopper (8) is also connected to the inlet of the second forming mold (5). The method includes the following steps: S1. Preparation of shaped phase change materials; S2. Mix and stir the shaped phase change material with the thermal grease to form a slurry material; S3. PE material is fed into the first feeding hopper (1). The PE material is first fed into the shearing machine (2). The shearing machine (2) cuts the PE material into small granules. The small granules of PE material are then fed into the heating mechanism (3). The heating mechanism (3) melts the PE material into a liquid state. The liquid PE material is then fed into the first forming mold (4). The first forming mold (4) extrudes the PE material into a tube shape. S4. Pass the PE pipe that has not yet been shaped into the second forming mold (5), and at the same time put the slurry material into the second feeding hopper (8) so that the slurry material adheres to the surface of the PE pipe. S5. Pass the attached PE pipe into the cooling mechanism (6) to cool and set its shape; S6. Pass the shaped PE pipe into the sealing machine (7) and completely wrap the attached PE pipe with PE film to obtain a self-sealing heat exchanger straight pipe. S7. Further process the prepared self-encapsulated heat exchanger straight tube to form the required length and spiral parameters.

2. The method for preparing a self-encapsulated spiral embedded tube heat exchanger according to claim 1, characterized in that: A vacuum layer is provided outside the return water pipe of the spiral buried tube heat exchanger.

3. The method for preparing a self-encapsulated spiral embedded tube heat exchanger according to claim 1, characterized in that: The shaped phase change material is prepared by adsorbing paraffin onto expanded graphite, wherein the mass ratio of expanded graphite to paraffin is 1:10, and the preparation method is vacuum impregnation.

4. The method for preparing a self-encapsulated spiral embedded tube heat exchanger according to claim 3, characterized in that: The specific steps for preparing shape-stabilized phase change materials are as follows: 1) Place the expanded graphite in a container and let it stand at 120°C for 12 hours; 2) Add paraffin wax to expanded graphite at a mass ratio of 1:10; 3) Place the container containing paraffin and expanded graphite in a vacuum drying oven for vacuum adsorption. The vacuum level is 0.08 MPa and the temperature is 50°C. The entire process needs to last for 10 hours, during which the container is taken out and stirred once every 2 hours.

5. The method for preparing a self-encapsulated spiral embedded tube heat exchanger according to claim 1, characterized in that: The self-encapsulating heat exchanger straight tubes are processed into the required spiral parameters using a tube bending machine.

6. A spiral embedded tube heat exchanger, characterized in that: The self-encapsulated spiral buried tube heat exchanger is prepared by any one of claims 1-5.

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