CN209857410U

CN209857410U - Geothermal well coiled pipe heat exchanger

Info

Publication number: CN209857410U
Application number: CN201920291728.2U
Authority: CN
Inventors: 张林辉; 李占英; 李淑恒; 李春兰; 王森; 雷军民; 杨进纳; 王洋; 郭超; 何婷婷; 高哲; 王秋环
Original assignee: LANZHOU LANSHI ENERGY EQUIPMENT ENGINEERING RESEARCH INSTITUTE
Current assignee: LANZHOU LANSHI ENERGY EQUIPMENT ENGINEERING RESEARCH INSTITUTE
Priority date: 2019-03-08
Filing date: 2019-03-08
Publication date: 2019-12-27
Anticipated expiration: 2029-03-08

Abstract

A geothermal well pipe-wound heat exchanger belongs to the geothermal energy development and utilization technology, and the upper part of the structure of the geothermal well pipe-wound heat exchanger is a metal sleeve heat insulation area I, and the lower part of the structure of the geothermal well pipe-wound heat exchanger is a pipe-wound heat exchanger area II; the metal sleeve heat preservation area I structurally comprises a metal outer sleeve and an inner sleeve; the second structure of the pipe-wound heat exchanger area is a circular barrel body surrounded by a central shaft pipe, a metal sieve pipe, an upper pipe plate and a lower pipe plate; the central shaft tube and the upper end of the metal sieve tube are respectively in sealing butt joint with the inner sleeve and the metal outer sleeve at the upper tube plate; the lower ends of the central shaft tube and the metal sieve tube are in sealed butt joint with the lower hemispherical shell at the lower tube plate; winding the pipe in the circular barrel around the central shaft pipe; the upper end and the lower end of the winding pipe are connected with the openings of the upper pipe plate and the lower pipe plate and are respectively communicated with the metal sleeve heat preservation area I and the central pipe flow channel; the length of the metal sleeve heat preservation area I ensures that the pipe-wound heat exchanger area II extends into the main heat exchange area of underground high-temperature geothermal heat. The utility model discloses wholly be closed system, realized that geothermal deep well gets heat and does not get water, heat exchange efficiency is high, is applicable to the geothermal well that multiple type is complicated.

Description

Geothermal well coiled pipe heat exchanger

Technical Field

The invention belongs to the technology of development and utilization of geothermal energy, and particularly relates to a geothermal well heat exchanger.

Background

The geothermal energy is wide in distribution, large in reserve, rapid in regeneration and high in utilization value. The geothermal heating technology is a new green energy heating technology which is environment-friendly and advocated by the government. In recent years, with the development of ground source heat pump heating technology, deep well geothermal technology is increasingly applied because a single well has large heat extraction amount and has minimal influence on ground buildings and ground surface temperature. The improvement of the single-well heat extraction is an important direction of the deep-well geothermal development technology and is also a technical difficulty. The size of heat taken by the same-specification well type single well of the geothermal well directly influences the initial investment of a geothermal heating system, namely influences the construction cost of unit heating area. The improvement of the heat extraction amount of the single well is very important for the wide popularization of the geothermal heating technology. In the aspect of deep well heat exchange technology, the coaxial buried pipe is mostly utilized in the prior art, the structure is simple, the single well heat exchange quantity is small, and even if the well aperture is enlarged, the effect of improving the heat exchange quantity is not obvious.

Disclosure of Invention

The invention aims to fully utilize the space in the well to enlarge the geothermal heat exchange area and furthest promote the heat extraction of a single well.

The invention discloses a coiled pipe heat exchanger for a geothermal well, which is structurally divided into an upper part and a lower part, wherein the upper part is a metal casing pipe area I, and the lower part is a metal coiled pipe heat exchange area II; the metal casing area I comprises a metal outer casing 10 and an inner casing 11, a well side water inlet or outlet channel is arranged between the metal outer casing 10 and the inner casing 11, the inner casing 11 is coated with a heat insulation material or adopts a heat insulation structure, and the inside of the inner casing is provided with a well side water outlet or inlet channel; the metal pipe-wound heat exchange area II is a circular barrel body surrounded by a central shaft tube 7, a metal sieve tube 6, an upper pipe plate 8 and a lower pipe plate 3; the central shaft tube 7 and the upper end of the metal sieve tube 6 are respectively in sealing butt joint with the inner sleeve 11 and the metal outer sleeve 10 at the upper tube plate 8; the lower ends of the central shaft tube 7 and the metal sieve tube 6 are in sealed butt joint with the lower hemispherical shell 1 at the lower tube plate 3; a winding pipe 5 is wound around a central shaft pipe 7 in the circular barrel body, and a brace 4 supports the winding pipe 5; wherein the upper tube plate 8 is provided with an upper opening 9, and the lower tube plate 3 is provided with a lower opening 2; the upper end of the winding pipe 5 is connected with an upper opening 9 and communicated with a flow channel between an inner sleeve and an outer sleeve of the metal sleeve area I, the lower end of the winding pipe 5 is connected with a lower opening 2, and the lower end hemisphere shell 1 which is connected with the lower end in a sealing mode is communicated with a flow channel of the central shaft pipe 7; the length of the upper metal sleeve pipe area I needs to ensure that the metal winding pipe heat exchange area II extends into the main heat exchange area of underground high-temperature geothermal heat; the length of the lower metal-wound heat exchange zone II can meet the requirement of heat extraction.

The structure form of the screen hole 12 of the metal screen 6 can be one of various types such as a drilling type, a slot type, a grid type, a net type and the like.

When the geothermal well is a rock layer or a mortar layer, the metal screen pipe 6 of the metal-wrapped heat exchange zone II can be removed, so that formation heat media such as rocks and mortar directly contact the wrapped pipe to enhance heat conduction.

The invention is an underground closed system as a whole, and the using method comprises the following steps: the intermediate water takes out the underground heat through the underground heat exchanger, and returns to the well for circulation after passing through the heat pump unit; there are two types of intermediate water flow paths in the well: the first way is that medium water enters a well between a metal outer sleeve 10 and an inner sleeve 11 → a pipe bundle of a winding pipe 5 → a sealed lower-end hemispherical shell 1 → a central shaft pipe 7 → an inner sleeve 11 goes out of the well → a heat pump unit, namely an external-in and internal-out mode; in the second mode, the intermediate water enters the well from the inner sleeve 11 → the central shaft tube 7 → the sealed lower hemispherical shell 1 → the pipe bundle of the winding pipe 5 → the outlet between the metal outer sleeve 10 and the inner sleeve 11 → the heat pump unit, namely, the mode of entering and exiting.

When the flow path of the intermediate water in the well is in a mode of a second mode, namely an inward-entering mode and an outward-going mode, the metal outer sleeve 10 of the invention is also coated with a heat-insulating material or adopts a heat-insulating structure.

According to the installation method, the upper metal casing pipe area I is divided into a plurality of sections before installation, and the section open caisson is installed during installation; the lower part of the metal pipe-wound heat exchange area II is divided into a plurality of sections before installation, and the lower part of the metal pipe-wound heat exchange area II is installed in a sectional open caisson mode during installation; the sections are connected by welding or screw thread.

The invention has the advantages that: the 'heat taking and water not taking' of the geothermal deep well is realized, and the application range of the geothermal is expanded; the problems of less single-well heat extraction quantity, low heat exchange efficiency, large thermal resistance of a well cementation layer, small heat transfer area of a casing and the like of a common casing heat exchanger in the prior art are effectively solved; the single-well heating load is greatly improved, the well drilling depth requirement is reduced, and the heat extraction device has the characteristics of stable heat extraction and high heat exchange efficiency.

Drawings

Fig. 1 is a schematic structural diagram of a geothermal well pipe-wound heat exchanger, wherein:

i is the upper part of the metal sleeve area

II is a heat exchange zone with a lower part of metal winding pipe

FIG. 2 is an enlarged view of the point A shown in FIG. 1

The following are marked in the figure: 1, a hemispherical shell at the lower end, 2 lower holes, 3 lower tube plates, 4 brace rods, 5 winding tubes, 6 metal sieve tubes, 7 central shaft tubes, 8 upper tube plates, 9 upper holes, 10 metal outer sleeves, 11 inner sleeves and 12 sieve tube holes.

Detailed Description

The invention is further explained with reference to the accompanying drawings.

As shown in fig. 1, the structure of a coiled tube heat exchanger for a geothermal well is divided into an upper part and a lower part, wherein the upper part is a metal casing tube area I, and the lower part is a metal coiled tube heat exchange area II; the metal casing area I comprises a metal outer casing 10 and an inner casing 11, a well side water inlet or outlet channel is arranged between the metal outer casing 10 and the inner casing 11, the inner casing 11 is coated with a heat insulation material or adopts a heat insulation structure, and the inside of the inner casing is provided with a well side water outlet or inlet channel; as shown in fig. 1 and 2, the metal-wrapped heat exchange zone ii is a circular barrel surrounded by an upper tube plate 8, a lower tube plate 3, a central shaft tube 7 and a metal sieve tube 6; the central shaft tube 7 and the upper end of the metal sieve tube 6 are respectively in sealing butt joint with the inner sleeve 11 and the metal outer sleeve 10 at the upper tube plate 8; the lower ends of the central shaft tube 7 and the metal sieve tube 6 are in sealed butt joint with the lower hemispherical shell 1 at the lower tube plate 3; a winding pipe 5 is wound around a central shaft pipe 7 in the circular barrel body, and a brace 4 supports the winding pipe 5; the upper tube plate 8 is provided with an upper opening 9, the lower tube plate 3 is provided with a lower opening 2, the upper end of the winding tube 5 is connected with the upper opening 9 and communicated with a flow channel between the sleeves of the metal sleeve pipe area I, the lower end of the winding tube 5 is connected with the lower opening 2 and communicated with a flow channel of the central shaft tube 7 through the lower hemispherical shell 1 which is connected in a sealing way; the length of the upper metal sleeve pipe area I needs to ensure that the metal winding pipe heat exchange area II extends into the main heat exchange area of underground high-temperature geothermal heat; the length of the lower part metal-wrapped heat exchange zone II can meet the requirement of heat extraction.

The structure form of the screen hole 12 of the metal screen 6 can be various types such as drilling, slotting, grid rod type, net type and the like.

The metal screen pipe 6 of the heat exchange zone II of the part of the metal-wrapped pipe can be selectively removed or reserved according to the actual condition when the well is drilled by the geothermal energy. When the groundwater layer is abundant, the sieve tube 6 structure is reserved, the winding pipe can be protected to avoid strong water flow impact, large gravel in water flow is filtered, and the gap between the winding pipe and the winding pipe is prevented from being filled, so that heat transfer is reduced.

When the geothermal well is a rock layer or a mortar layer, the metal screen pipe 6 of the metal-wrapped heat exchange zone II can be omitted, so that formation heat media such as rocks and mortar directly contact the wrapped pipe, heat conduction is enhanced, and heat efficiency is improved.

The invention is an underground closed system as a whole, and the using method comprises the following steps: the intermediate water takes out the underground heat through the underground heat exchanger, and returns to the well for circulation after passing through the heat pump unit; the use process, namely the flow path of the intermediate water in the well, has two types: the first way is that medium water enters a well between a metal outer sleeve 10 and an inner sleeve 11 → a pipe bundle of a winding pipe 5 → a sealed lower-end hemispherical shell 1 → a central shaft pipe 7 → an inner sleeve 11 goes out of the well → a heat pump unit, namely an external-in and internal-out mode; in the second mode, the intermediate water enters the well from the inner sleeve 11 → the central shaft tube 7 → the sealed lower hemispherical shell 1 → the pipe bundle of the winding pipe 5 → the outlet between the metal outer sleeve 10 and the inner sleeve 11 → the heat pump unit, namely, the mode of entering and exiting. The intermediate water gets heat from the underground through the underground pipe-wound heat exchanger, so that the temperature of the intermediate water is increased, the high-temperature intermediate water enters the heat pump unit and transfers the heat to the water at the tail end of the heating, so that the temperature of the intermediate water is reduced, and the low-temperature intermediate water is injected into the well again for heat exchange, thereby completing the cycle of geothermal heat acquisition.

According to the installation method, the upper metal casing pipe area I is divided into a plurality of sections before installation, and the section open caisson is installed during installation; and the lower part metal pipe-wound heat exchange area II consists of a plurality of sections of pipe-wound heat exchangers, the heat exchangers are installed by sections in open caisson installation, and the sections are connected by welding or threads.

In practice, the total length of the upper metal sleeve area I can reach 1000m ~ 2000m, the upper metal sleeve area I is divided into a plurality of sections before installation, the length of each section is 3m ~ 12m, the total length of the lower metal coiled heat exchange area II can reach 100m ~ 1500m, the lower metal coiled heat exchange area I is divided into a plurality of sections before installation, and the length of each section is 3m ~ 12 m.

The invention realizes 'no water taking when heat is taken from the geothermal deep well', has more heat taking amount of a single well, high heat exchange efficiency and stable heat taking, can be used for various complicated geothermal wells, and has wide application range.

Claims

1. Geothermal well is around a tub heat exchanger, characterized by: the structure of the device is divided into an upper part and a lower part, wherein the upper part is a metal sleeve pipe area (I), and the lower part is a metal winding pipe heat exchange area (II); the structure of the metal sleeve area (I) is provided with a metal outer sleeve and an inner sleeve, a well side water inlet or outlet channel is arranged between the metal outer sleeve and the inner sleeve, the inner sleeve is coated with a heat insulation material or adopts a heat insulation structure, and the inside of the inner sleeve is provided with a well side water outlet or inlet channel; the metal pipe-wound heat exchange area (II) is structurally surrounded by a central shaft tube and a metal sieve tube, an upper pipe plate and a lower pipe plate, and a circular barrel body is formed by encircling the central shaft tube and the metal sieve tube; the upper end of the central shaft tube and the upper end of the metal screen tube are in sealed butt joint with the inner sleeve heat exchanger and the metal outer sleeve at the upper tube plate and the lower tube plate respectively; the lower end of the central shaft tube and the lower end of the metal screen tube are in sealing butt joint with the lower hemispherical shell at the position three of the lower tube plate; the winding pipe is wound around the central axle tube and is wound around the central axle tube in the circular barrel body, and the winding pipe is supported by the brace fourth; the upper tube plate is provided with an upper tapping hole, the lower tube plate is provided with a lower tapping hole, and the lower tapping hole is formed in the lower tube plate; the upper end of the winding pipe is connected with the upper tapping hole and penetrates through a runner between an inner sleeve and an outer sleeve of the metal sleeve area (I), the lower end of the winding pipe is connected with the lower tapping hole, and the lower end semispherical shell in sealing connection penetrates through a central shaft pipe heat runner; the length of the upper part of the metal sleeve pipe area (I) needs to ensure that the metal winding pipe heat exchange area (II) extends into the main heat exchange area of underground high-temperature geothermal heat; the length of the lower metal-wrapped heat exchange zone (II) needs to meet the requirement of heat extraction.

2. The geothermal well coiled tube heat exchanger of claim 1, wherein: the screen hole water pumping structure form of the metal screen pipe can be one of various types such as a drilling type, a slotting type, a grid rod type or a net type.

3. The geothermal well coiled tube heat exchanger of claim 1, wherein: and when the geothermal well is a lithosphere or a mortar layer, removing the metal screen pipe of the metal winding pipe heat exchange area (II).

4. The geothermal well coiled tube heat exchanger of claim 1, wherein: when the flow path of the intermediate water in the well is in an inward-going and outward-going mode, the metal outer sleeve is also coated with a heat-insulating material or adopts a heat-insulating structure.