CN116659105A - Geothermal energy cascade utilization heat exchange system and geothermal energy cascade utilization method - Google Patents

Geothermal energy cascade utilization heat exchange system and geothermal energy cascade utilization method Download PDF

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Publication number
CN116659105A
CN116659105A CN202310572688.XA CN202310572688A CN116659105A CN 116659105 A CN116659105 A CN 116659105A CN 202310572688 A CN202310572688 A CN 202310572688A CN 116659105 A CN116659105 A CN 116659105A
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China
Prior art keywords
telescopic
outer tube
heat
pipe
wall
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CN202310572688.XA
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Chinese (zh)
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赵军威
林琳
朱明玥
王磊
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Shandong Dehe Geothermal Development Co ltd
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Shandong Dehe Geothermal Development Co ltd
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Priority to CN202310572688.XA priority Critical patent/CN116659105A/en
Publication of CN116659105A publication Critical patent/CN116659105A/en
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24TGEOTHERMAL COLLECTORS; GEOTHERMAL SYSTEMS
    • F24T10/00Geothermal collectors
    • F24T10/10Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground
    • F24T10/13Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes
    • F24T10/17Geothermal collectors with circulation of working fluids through underground channels, the working fluids not coming into direct contact with the ground using tube assemblies suitable for insertion into boreholes in the ground, e.g. geothermal probes using tubes closed at one end, i.e. return-type tubes
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/10Geothermal energy

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The invention belongs to the technical field of geothermal energy development, and particularly relates to a geothermal energy cascade utilization heat exchange system and a geothermal energy cascade utilization method.

Description

Geothermal energy cascade utilization heat exchange system and geothermal energy cascade utilization method
Technical Field
The invention belongs to the technical field of geothermal energy development, and particularly relates to a geothermal energy cascade utilization heat exchange system and a geothermal energy cascade utilization method.
Background
The traditional geothermal heating mode is a geothermal water heating system, geothermal water is directly input into a heating pipe network after being simply treated, but the problem of recharging and blocking is usually caused by factors such as stratum pressure, sediment and the like, and a large amount of extracted groundwater can cause damages such as unbalance of groundwater, ground subsidence, environmental pollution and the like. The coaxial sleeve type heat exchanger can indirectly extract high-temperature groundwater/geotechnical heat through closed circulation of circulating working medium fluid, achieves the effect of 'taking heat without taking water', avoids recharging geothermal tail water, and is a simple and clean way for utilizing geothermal energy. The method can be widely applied to various geological conditions, the investment of drilling cost is reduced by a single well (hole) working mode, the economic benefit is improved in an optimized way, and the method has a very wide application prospect.
The inner tube and the outer tube of the conventional coaxial double-tube heat exchanger are fixed in position, and heat of high-temperature rock stratum or underground water at the bottom of a well is extracted to heat the well by placing the heat exchanger at the bottom of the well. However, for the whole heating phase, the heating load is in continuous dynamic change, and the heat load has peak and valley phases, and the demand of the heating amount is different in different phases. The relatively fixed position of the medium-deep coaxial double-pipe heat exchanger makes the heat extraction not dynamically adjustable according to the heat load requirement. In the low heat load stage, heat is excessively extracted, and heat outside heating cannot be fully utilized and is wasted; in the peak stage of heat load, heat cannot be recovered in time due to excessive heat taking before, so that insufficient heat supply in the peak stage is caused.
Disclosure of Invention
The invention aims to solve the problems and provide a geothermal energy cascade utilization heat exchange system and a geothermal energy cascade utilization method.
The technical problems to be solved by the invention are realized by adopting the following technical scheme: the geothermal energy cascade utilization heat exchange system comprises a drilling well, a telescopic coaxial double-pipe heat exchanger and a traction device, wherein the telescopic coaxial double-pipe heat exchanger comprises a telescopic inner pipe and a telescopic outer pipe, and the telescopic outer pipe is a heat conducting pipe;
the telescopic outer pipe is vertically arranged in the well drilling, the telescopic inner pipe is vertically arranged in the telescopic outer pipe, the upper end of the telescopic outer pipe is provided with a water inlet, an opening at the bottom of the telescopic inner pipe is communicated with the telescopic outer pipe, the upper end of the telescopic inner pipe is provided with a water outlet, and the lower end of the telescopic outer pipe is closed;
the telescopic inner pipe comprises a first inner pipe and a second inner pipe, the first inner pipe is fixedly arranged in the well drilling, the second inner pipe is sleeved outside the lower end of the first inner pipe in a vertically sliding manner, a first sealing ring is arranged between the first inner pipe and the second inner pipe, and the first sealing ring is arranged at the lower end of the first inner pipe or the upper end of the second inner pipe;
the telescopic outer pipe comprises a first outer pipe and a second outer pipe, the first outer pipe is fixedly arranged in the well, the second outer pipe is sleeved outside the lower end of the first outer pipe in a vertically sliding mode, a second sealing ring is arranged between the first outer pipe and the second outer pipe, and the second sealing ring is arranged at the lower end of the first outer pipe or the upper end of the second outer pipe;
the second inner pipe is fixedly connected with the second outer pipe;
the traction device is used for controlling the lifting of the second outer pipe.
The technical scheme of the invention is as follows: the second sealing ring is arranged at the lower end of the first outer tube, and the pressing type spring heat conducting pins are positioned above the second sealing ring;
the pressing type spring heat conduction pin is arranged along the radial direction of the first outer tube;
when the pressing type spring heat conduction pin is positioned between the outer wall of the first outer tube and the inner wall of the second outer tube, the pressing type spring heat conduction pin is in a compressed state, and the top end of the pressing type spring heat conduction pin is in contact with the inner wall of the second outer tube;
when the push type spring heat conduction pin is positioned between the outer wall of the first outer tube and the inner wall of the well, the push type spring heat conduction pin is in an extending state, and the top end of the push type spring heat conduction pin is in contact with the inner wall of the well. The pressing type spring heat conducting pin is arranged on the outer wall of the first outer tube, and is arranged along the radial direction of the first outer tube, so that the pressing type spring heat conducting pin can be extruded to shrink when the outer wall of the first outer tube ascends, and is in a compressed state when the pressing type spring heat conducting pin is positioned between the outer wall of the first outer tube and the inner wall of the second outer tube, and the top end of the pressing type spring heat conducting pin is in contact with the inner wall of the second outer tube, so that a heat conducting effect is achieved between the outer wall of the first outer tube and the inner wall of the second outer tube, and the heat conducting efficiency is improved; when the push type spring heat conduction pin is positioned between the outer wall of the first outer tube and the inner wall of the well, the push type spring heat conduction pin is in an extending state, and the top end of the push type spring heat conduction pin is in contact with the inner wall of the well, so that heat of the side wall of the well is rapidly conducted to the inner wall of the second outer tube, and the heat transfer efficiency is improved.
The technical scheme of the invention is as follows: the pressing type spring heat conduction pin comprises a fixed sleeve, a sliding ejector rod and a telescopic spring;
the fixed sleeve is radially arranged on the outer wall of the first outer tube along the first outer tube, the sliding ejector rod can be axially and slidably arranged in the fixed sleeve along the fixed sleeve, and a telescopic spring is arranged between the sliding ejector rod and the fixed sleeve;
the top of the sliding ejector rod is conical or circular arc. Under the action of the telescopic spring, the sliding ejector rod can axially slide along the fixed sleeve, and because the top of the sliding ejector rod is conical or circular arc-shaped, when the second outer tube ascends, the side wall of the second outer tube extrudes the top of the sliding ejector rod to enable the sliding ejector rod to compress the telescopic spring into the fixed sleeve. When the top of the sliding ejector rod is not pressed, the sliding ejector rod stretches out of the fixed sleeve under the action of the telescopic spring.
The technical scheme of the invention is as follows: the traction device comprises a traction rope and a winding mechanism;
the lower end of the traction rope is connected with the second outer tube, and the upper end of the traction rope is connected with the winding mechanism. The lower end of the traction rope is connected with the second outer tube, the upper end of the traction rope is connected with the winding mechanism, the second outer tube and the second inner tube can be driven to slide upwards along the well when the winding mechanism is used for winding the traction rope upwards by increasing the traction rope upwards, and the second outer tube and the second inner tube can slide downwards along the well under the action of gravity when the winding mechanism is reduced to reduce the traction rope upwards by using the winding mechanism to lower the traction rope, so that the heat exchange position of the heat exchange system is adjusted.
The technical scheme of the invention is as follows: the telescopic inner tube is a heat insulation tube. The telescopic inner tube is a heat insulation tube, so that the heat insulation tube has good heat insulation performance, and heat exchange between high-temperature circulating fluid in the telescopic inner tube and low-temperature circulating fluid between the telescopic inner tube and the telescopic outer tube is avoided, and specifically, plastic tubes made of PE, PP, PVC and the like or composite structures with heat insulation materials embedded in and coated on the metal inner tube can be selected.
The technical scheme of the invention is as follows: the temperature sensor is arranged on the side wall of the well along the axial direction of the well;
the temperature sensor is used for monitoring the temperature of different depths of the well. Through set up temperature sensor on the well drilling lateral wall, carry out real-time supervision to the temperature of the different degree of depth of well drilling to the length of scalable inner tube, scalable outer tube is adjusted to reasonable, improves the utilization ratio to geothermal energy.
The technical scheme of the invention is as follows: the heat-insulating layer is arranged on the shallow drilling layer and is positioned between the inner drilling wall and the outer wall of the first inner tube. By arranging the heat preservation layer on the shallow earth surface, the heat preservation layer is arranged between the inner wall of the well drilling and the outer wall of the first inner tube, so that heat exchange between circulating fluid and the low-temperature earth surface is avoided, and heat loss is generated.
The technical scheme of the invention is as follows: the well drilling device also comprises a slideway vertically arranged on the side wall of the well drilling;
the outer wall of the second outer tube is provided with a sliding rail matched with the sliding rail, and the sliding rail of the second outer tube can be arranged in the sliding rail in a vertical sliding manner. Through set up vertical slide on the well drilling lateral wall, with slide rail and slide cooperation to play the effect of direction to the second outer tube, reduce the frictional force between second outer tube outer wall and the well drilling lateral wall, when the top traction force is less than gravity, guarantee that the second outer tube can slide downwards under the action of gravity.
The technical scheme of the invention is as follows: the connecting rod is arranged between the outer wall of the second inner tube and the inner wall of the second outer tube, and two ends of the connecting rod are respectively connected with the second inner tube and the second outer tube. The connecting rod is arranged between the outer wall of the second inner pipe and the inner wall of the second outer pipe, so that the second inner pipe can synchronously lift along with the second outer pipe, and the influence on the flow of circulating fluid is reduced due to the small volume of the connecting rod.
The invention also discloses a geothermal energy cascade utilization method, which adopts the geothermal energy cascade utilization heat exchange system and comprises the following steps:
s1, determining a heat taking position of a telescopic coaxial double-pipe heat exchanger according to heating daily heat load requirements, the daily air temperature, the time period and the temperature distribution of a rock and soil layer in a well;
s2, controlling the lifting of the second outer tube by using a traction device, and adjusting the lengths of the telescopic inner tube and the telescopic outer tube to a heat taking position set by drilling to take heat;
s3, monitoring the heat load demand, the air temperature and the dynamic change of the water temperature at the water outlet in real time, and timely adjusting the heat taking position of the telescopic coaxial double-pipe heat exchanger to realize the cascade utilization of geothermal energy.
Compared with the prior art, the invention has the beneficial effects that:
according to the invention, the telescopic outer tube is vertically arranged in the well, the telescopic inner tube is vertically arranged in the telescopic outer tube, and the telescopic outer tube is formed by sleeving the second outer tube at the outer side of the lower end of the first outer tube in a vertically sliding manner, and the telescopic inner tube is formed by sleeving the second inner tube at the outer side of the lower end of the first inner tube in a vertically sliding manner, and the second inner tube is fixedly connected with the second outer tube, so that the lifting of the second outer tube is controlled by the traction device, the positions of the telescopic inner tube and the lower end of the telescopic outer tube in the well can be simultaneously regulated, the utilization of geothermal energy at different depths is realized, the heat taking position of a heat exchange system in the well can be timely planned according to heating requirements, the heat taking position can be timely regulated, and the utilization rate of geothermal energy and the heat exchange efficiency between circulating fluid and a heat storage layer are improved.
Drawings
FIG. 1 is a schematic diagram of a geothermal energy cascade heat exchange system according to the present invention;
FIG. 2 is an enlarged view of a portion of the geothermal energy cascade heat exchange system of the present invention;
FIG. 3 is a schematic view of a pressed spring heat conducting pin according to the present invention in a compressed state;
FIG. 4 is a schematic view of the structure of the push-type spring heat conducting pin in an extended state;
FIG. 5 is a schematic illustration of the mating relationship of the second outer tube of the present invention with a borehole;
FIG. 6 is a schematic view of the structure of the telescopic outer tube according to the present invention;
FIG. 7 is a schematic diagram of the working principle of the geothermal energy cascade utilization heat exchange system according to the present invention;
in the figure, a well is drilled by 100 and a slideway is formed by 101;
200 water inlets, 300 water outlets and 400 filling layers;
1 a traction device, 11 a traction rope and 12 a winding mechanism;
2 a telescopic inner tube, 21 a first inner tube and 22 a second inner tube;
3, a telescopic outer tube, a 31 first outer tube, a 32 second outer tube, 321 sliding rails and 322 sealing heads;
4 a first sealing ring, 5 a second sealing ring and 6 a push type spring heat conducting pin;
61 fixing sleeve, 62 sliding ejector rod, 63 telescopic spring;
7 heat preservation and 8 connecting rods.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
As shown in fig. 1 and 2, the geothermal energy cascade heat exchange system comprises a well drilling 100, a telescopic coaxial double-pipe heat exchanger and a traction device 1, wherein the telescopic coaxial double-pipe heat exchanger comprises a telescopic inner pipe 2 and a telescopic outer pipe 3, and the telescopic outer pipe 3 is a heat conduction pipe. The telescopic outer tube 3 is made of excellent metal materials, so that the telescopic outer tube 3 has excellent heat conduction performance and compression and stretching performances, and particularly stainless steel, high-quality iron or copper and the like can be selected.
The telescopic outer tube 3 is vertically arranged in the well drilling 100, and a filling layer 400 is arranged between the outer wall of the telescopic outer tube 3 and the inner wall of the well drilling 100, so that the telescopic outer tube 3 is ensured to be in close contact with the well wall of the well drilling 100, and the heat transfer efficiency is improved. The telescopic inner pipe 2 is vertically arranged inside the telescopic outer pipe 3, a water inlet 200 is formed in the upper end of the telescopic outer pipe 3, an opening at the bottom of the telescopic inner pipe 2 is communicated with the telescopic outer pipe 3, a water outlet 300 is formed in the upper end of the telescopic inner pipe 2, and the lower end of the telescopic outer pipe 3 is sealed.
The telescopic inner pipe 2 comprises a first inner pipe 21 and a second inner pipe 22, the first inner pipe 21 is fixedly arranged in the well drilling 100, the second inner pipe 22 is sleeved outside the lower end of the first inner pipe 21 in a vertically sliding mode, a first sealing ring 4 is arranged between the first inner pipe 21 and the second inner pipe 22, and the first sealing ring 4 is arranged at the lower end of the first inner pipe 21. The first sealing ring 4 plays a role of sealing against heat exchange between the high-temperature circulating fluid in the telescopic inner tube 2 and the low-temperature circulating fluid in the telescopic outer tube 3.
The telescopic outer tube 3 comprises a first outer tube 31 and a second outer tube 32, the first outer tube 31 is fixedly arranged in the well drilling 100, the second outer tube 32 is sleeved outside the lower end of the first outer tube 31 in a vertically sliding mode, the outer wall of the second outer tube 32 is tightly attached to a high-temperature rock stratum on the side wall of the well drilling 100, circulating fluid is guaranteed to exchange heat with the high-temperature rock stratum/underground water fully, an elliptical sealing head 332 is arranged at the lower end of the second outer tube 32, a second sealing ring 5 is arranged between the first outer tube 31 and the second outer tube 32, and the second sealing ring 5 is arranged at the lower end of the first outer tube 31. The second sealing ring 5 plays a role in sealing, and prevents low-temperature circulating fluid in the telescopic outer tube 3 from flowing out to influence the heat exchange process of the circulating fluid.
Specifically, the first inner tube 21 and the second inner tube 22 are made of PVC materials, and have good heat insulation performance. The first outer tube 31 and the second outer tube 32 are made of stainless steel materials, and have excellent heat conduction performance, compression resistance and tensile performance.
The second inner tube 22 is fixedly connected to the second outer tube 32. The circulating fluid is deaerated purified water, flows in from the water inlet 200, flows along the inner wall of the telescopic outer tube 3, exchanges heat with high-temperature rock stratum/underground water on the side wall of the well drilling 100, then turns into high-temperature circulating fluid, enters the telescopic inner tube 2 along the elliptical seal head 332, flows to the ground along the telescopic inner tube 2, exchanges heat with a heat exchange pipe network, and returns to the telescopic outer tube 3 again to complete one-time circulation.
The traction device 1 is used for controlling the lifting of the second outer tube 32.
The traction force of the traction device 1 on the second outer tube 32 is F, the gravity of the second outer tube 32 is G1, the gravity of the second inner tube 22 is G2, the maximum static friction force received by the second outer tube 32 is F1, and the maximum static friction force received by the second inner tube 22 is F2.
When F > G1+G2+f1+f2, the second outer tube 32 and the second inner tube 22 rise together.
When F < G1+G2-F1-F2, the second outer tube 32 and the second inner tube 22 are lowered simultaneously.
When G1+G2-f1-f2.ltoreq.F.ltoreq.G1+G2+f1+f2, the second outer tube 32 and the second inner tube 22 will remain stationary.
The geothermal energy cascade utilization heat exchange system further comprises pressing type spring heat conduction pins 6 distributed on the outer wall of the first outer tube 31, and the pressing type spring heat conduction pins 6 are located above the second sealing ring 5.
The push-type spring heat conducting pin 6 is arranged radially along the first outer tube 31. The material of the push type spring heat conduction pin 6 is the same as that of the first outer tube 31, and the push type spring heat conduction pin is reliably connected in a welding mode.
As shown in fig. 2 and 3, when the push-type spring heat conducting pin 6 is located between the outer wall of the first outer tube 31 and the inner wall of the second outer tube 32, the top end of the push-type spring heat conducting pin 6 is in contact with the inner wall of the second outer tube 32, so as to fill the gap between the outer wall of the first outer tube 31 and the inner wall of the second outer tube 32.
As shown in fig. 2 and 4, when the push type spring heat conducting pin 6 is located between the outer wall of the first outer tube 31 and the inner wall of the well 100, the top end of the push type spring heat conducting pin 6 is in contact with the inner wall of the well 100. The first outer tube 31 is only provided with the push type spring heat conduction pins 6 in an array in the non-heat-preservation area, and is used for tightly connecting the first outer tube 31 with the second outer tube 32 or a high-temperature rock stratum to effectively transfer heat.
Specifically, as shown in fig. 3 and 4, the push-type spring heat conducting pin 6 includes a fixed sleeve 61, a sliding push rod 62 and a telescopic spring 63.
The fixed sleeve 61 is radially arranged on the outer wall of the first outer tube 31 along the first outer tube 31, the sliding ejector rod 62 is axially and slidably arranged in the fixed sleeve 61 along the fixed sleeve 61, a telescopic spring 63 is arranged between the sliding ejector rod 62 and the fixed sleeve 61, and the telescopic spring 63 is positioned between the bottom of the sliding ejector rod 62 and the bottom of the inner cavity of the fixed sleeve 61.
The top of the sliding ejector rod 62 is arc-shaped.
Specifically, as shown in fig. 1 and 2, the traction device 1 includes a traction rope 11 and a winding mechanism 12.
The lower end of the hauling cable 11 is connected with the second outer tube 32, and the upper end of the hauling cable 11 is connected with the winding mechanism 12.
The telescopic inner tube 2 is a thermal insulation tube.
The geothermal energy cascade heat exchange system further comprises a temperature sensor axially disposed on the side wall of the well 100 along the well 100.
The temperature sensors are used to monitor the temperature of the well 100 at different depths.
As shown in fig. 1 and 2, the geothermal energy cascade heat exchange system further comprises a heat insulation layer 7 disposed on a shallow layer of the well 100, and the heat insulation layer 7 is located between an inner wall of the well 100 and an outer wall of the first inner tube 21.
As shown in fig. 5, the geothermal energy cascade heat exchange system further includes a skid 101 vertically disposed on a sidewall of the well 100.
As shown in fig. 5 and 6, the outer wall of the second outer tube 32 is provided with a sliding rail 321 matched with the sliding rail 101, and the sliding rail 321 of the second outer tube 32 is slidably arranged in the sliding rail 101 up and down.
As shown in fig. 2, the geothermal energy cascade heat exchange system further includes a connecting rod 8, wherein the connecting rod 8 is disposed between the outer wall of the second inner tube 22 and the inner wall of the second outer tube 32, and two ends of the connecting rod 8 are respectively connected with the second inner tube 22 and the second outer tube 32.
The geothermal energy cascade utilization method adopts the geothermal energy cascade utilization heat exchange system, and comprises the following steps:
s1, determining the heat taking position of the telescopic coaxial double-pipe heat exchanger according to the heating daily heat load demand, the daily air temperature, the time period and the temperature distribution of the rock and soil layers in the well 100. As shown in fig. 7, the temperature distribution of the rock and soil layer in the well 100 is collected during the well drilling, and a data reference is provided for the determination of the later heat-taking position, and the temperature of rock and soil layers with different depths can be monitored and collected in real time by arranging temperature sensors in the well drilling during the later use process due to the change of the temperature of the soil layers with different seasons and different times Duan Yan. The specific method for determining the heat extraction position of the telescopic coaxial double pipe heat exchanger is not a protection content of the present invention, and will not be described herein.
S2, controlling the lifting of the second outer pipe 32 by using the traction device 1, and adjusting the lengths of the telescopic inner pipe 2 and the telescopic outer pipe 3 to the set heat extraction position of the well 100 to extract heat.
S3, monitoring the heat load demand, the air temperature and the dynamic change of the water temperature at the water outlet 300 in real time, and timely adjusting the heat taking position of the telescopic coaxial double-pipe heat exchanger to realize the cascade utilization of geothermal energy.
Specifically, during periods of initial and final heating at higher air temperatures, thermal energy from shallower formations of the well 100 may be used; the thermal energy of the deeper formations of the well 100 is used during periods of lower mid-heating air temperatures.
Specifically, during the daytime of heating, heat energy from the shallow formation of the well 100 may be used to heat, and during the nighttime of heating, heat energy from the deep formation of the well 100 may be used to heat.
Specifically, the shallow geothermal energy and the deep geothermal energy of the well 100 are intermittently utilized, so that the phenomenon of cold accumulation is avoided, and the utilization rate of the geothermal energy is improved.
The invention has the advantages that:
1) The telescopic coaxial double-pipe heat exchanger has a telescopic structure, the heat taking position of the telescopic coaxial double-pipe heat exchanger in the well 100 can be reasonably adjusted according to the heat load requirement, the gradient utilization of geothermal energy is realized, and the geothermal energy utilization rate is improved.
2) By intermittently utilizing the formation heat energy of different depths, intermittent heat extraction is performed on shallow geothermal heat and deep geothermal heat of the well 100, so that the phenomenon of cold accumulation is avoided, and the heat exchange capacity of the heat exchanger is improved.
3) The heat exchange structure and the heat preservation arrangement of the heat exchange system are reasonable in distribution, the heat preservation layer 7 is arranged on the shallow earth surface with lower temperature, heat loss of circulating fluid on the shallow earth surface is reduced, and the pressing type spring heat conduction pin 6 is arranged on the outer wall of the first outer tube 31 with higher depth, so that the heat exchange effect is enhanced.

Claims (10)

1. The utility model provides a geothermal energy cascade utilization heat transfer system which characterized in that: the heat pipe type telescopic heat exchanger comprises a drilling well (100), a telescopic coaxial sleeve heat exchanger and a traction device (1), wherein the telescopic coaxial sleeve heat exchanger comprises a telescopic inner pipe (2) and a telescopic outer pipe (3), and the telescopic outer pipe (3) is a heat-conducting pipe;
the telescopic outer pipe (3) is vertically arranged in the well drilling (100), the telescopic inner pipe (2) is vertically arranged in the telescopic outer pipe (3), a water inlet (200) is formed in the upper end of the telescopic outer pipe (3), an opening at the bottom of the telescopic inner pipe (2) is communicated with the telescopic outer pipe (3), a water outlet (300) is formed in the upper end of the telescopic inner pipe (2), and the lower end of the telescopic outer pipe (3) is arranged in a closed mode;
the telescopic inner pipe (2) comprises a first inner pipe (21) and a second inner pipe (22), the first inner pipe (21) is fixedly arranged in the well drilling (100), the second inner pipe (22) is sleeved outside the lower end of the first inner pipe (21) in a vertically sliding mode, a first sealing ring (4) is arranged between the first inner pipe (21) and the second inner pipe (22), and the first sealing ring (4) is arranged at the lower end of the first inner pipe (21) or the upper end of the second inner pipe (22);
the telescopic outer tube (3) comprises a first outer tube (31) and a second outer tube (32), the first outer tube (31) is fixedly arranged in the well drilling (100), the second outer tube (32) is sleeved outside the lower end of the first outer tube (31) in a vertically sliding mode, a second sealing ring (5) is arranged between the first outer tube (31) and the second outer tube (32), and the second sealing ring (5) is arranged at the lower end of the first outer tube (31) or the upper end of the second outer tube (32);
the second inner tube (22) is fixedly connected with the second outer tube (32);
the traction device (1) is used for controlling the lifting of the second outer pipe (32).
2. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the novel heat-conducting structure is characterized by further comprising pressing type spring heat-conducting pins (6) distributed on the outer wall of the first outer tube (31), wherein the second sealing ring (5) is arranged at the lower end of the first outer tube (31), and the pressing type spring heat-conducting pins (6) are positioned above the second sealing ring (5);
the pressing type spring heat conduction pin (6) is radially arranged along the first outer tube (31);
when the pressing type spring heat conduction pin (6) is positioned between the outer wall of the first outer tube (31) and the inner wall of the second outer tube (32), the pressing type spring heat conduction pin is in a compressed state, and the top end of the pressing type spring heat conduction pin (6) is in contact with the inner wall of the second outer tube (32);
when the push type spring heat conduction pin (6) is positioned between the outer wall of the first outer tube (31) and the inner wall of the well (100), the push type spring heat conduction pin is in an extending state, and the top end of the push type spring heat conduction pin (6) is in contact with the inner wall of the well (100).
3. The geothermal energy cascade utilization heat exchange system of claim 2, wherein: the push type spring heat conduction pin (6) comprises a fixed sleeve (61), a sliding ejector rod (62) and a telescopic spring (63);
the fixed sleeve (61) is radially arranged on the outer wall of the first outer tube (31) along the first outer tube (31), the sliding ejector rod (62) can be axially and slidably arranged in the fixed sleeve (61) along the fixed sleeve (61), and a telescopic spring (63) is arranged between the sliding ejector rod (62) and the fixed sleeve (61);
the top of the sliding ejector rod (62) is conical or circular arc.
4. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the traction device (1) comprises a traction rope (11) and a winding mechanism (12);
the lower end of the traction rope (11) is connected with the second outer tube (32), and the upper end of the traction rope (11) is connected with the winding mechanism (12).
5. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the telescopic inner tube (2) is a heat insulation tube.
6. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the system also comprises a temperature sensor which is axially arranged on the side wall of the well (100) along the well (100);
the temperature sensor is used to monitor the temperature of different depths of the borehole (100).
7. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the heat-insulating layer (7) is arranged on the shallow layer of the well drilling (100), and the heat-insulating layer (7) is positioned between the inner wall of the well drilling (100) and the outer wall of the first inner tube (21).
8. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the well drilling device also comprises a slideway (101) vertically arranged on the side wall of the well drilling device (100);
the outer wall of the second outer tube (32) is provided with a sliding rail (321) matched with the sliding rail (101), and the sliding rail (321) of the second outer tube (32) can be arranged in the sliding rail (101) in a vertical sliding mode.
9. The geothermal energy cascade utilization heat exchange system of claim 1, wherein: the novel connecting rod comprises a first inner pipe (22) and a second outer pipe (32), and is characterized by further comprising a connecting rod (8), wherein the connecting rod (8) is arranged between the outer wall of the second inner pipe (22) and the inner wall of the second outer pipe (32), and two ends of the connecting rod (8) are respectively connected with the second inner pipe (22) and the second outer pipe (32).
10. A geothermal energy cascade utilization method, which adopts the geothermal energy cascade utilization heat exchange system of any one of claims 1 to 9, comprising the steps of:
s1, determining a heat taking position of a telescopic coaxial double-pipe heat exchanger according to heating daily heat load requirements, daily air temperature, time period and temperature distribution of a rock and soil layer in a well (100);
s2, controlling the lifting of the second outer pipe (32) by using the traction device (1), and adjusting the lengths of the telescopic inner pipe (2) and the telescopic outer pipe (3) to the heat extraction position set by the well drilling (100) to extract heat;
s3, monitoring the heat load demand, the air temperature and the dynamic change of the water temperature at the water outlet (300) in real time, and timely adjusting the heat taking position of the telescopic coaxial double-pipe heat exchanger to realize the cascade utilization of geothermal energy.
CN202310572688.XA 2023-05-18 2023-05-18 Geothermal energy cascade utilization heat exchange system and geothermal energy cascade utilization method Pending CN116659105A (en)

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