阅读说明：本技术 一种中深层闭式地热能供热系统及其设计方法 (Middle-deep layer closed geothermal energy heat supply system and design method thereof ) 是由 钟振楠 林少一 戴长国 霍光 周明岭 鲍中义 宋明忠 史云娣 傅朋远 李恒猛 柳 于 2020-11-11 设计创作，主要内容包括：本发明公开了一种中深层闭式地热能供热系统,包括沸气换热器模组,用于将换热介质送入地底且经过地底换热后引导输入至地下换热器模组的输入端；地下换热器模组,用于将换热后的换热介质和循环水进行二次换热,并将循环水泵送至单管循环管网,并通过单管循环管网向多级用户端进行逐级的输送,单管循环管网将多级用户端使用循环水后形成的回水输入至地下换热器模组；发电机组,用于与多级用户端并联的方式接入单管循环管网,将地下换热器模组泵入发电机组的换热介质和循环水功能分离,并将分离后产生的换热介质送入沸气换热器模组的输入端,分离后产生的循环水输送至单管循环管网,采用地下间接多介质组合换热,提高地热使用效率和系统供水稳定。(The invention discloses a middle-deep closed geothermal energy heating system, which comprises a boiling gas heat exchanger module, a heat exchanger and a heat exchanger control module, wherein the boiling gas heat exchanger module is used for sending a heat exchange medium into the ground, conducting heat exchange through the ground and then guiding the heat exchange medium to be input into the input end of an underground heat exchanger module; the underground heat exchanger module is used for carrying out secondary heat exchange on the heat exchange medium and circulating water after heat exchange, pumping the circulating water to the single-pipe circulating pipe network, and carrying out step-by-step conveying on the multi-stage user side through the single-pipe circulating pipe network; the generator set is connected into the single-pipe circulation pipe network in a parallel connection mode with the multistage user side, the heat exchange medium and the circulating water which are pumped into the generator set by the underground heat exchanger module are separated in function, the separated heat exchange medium is sent into the input end of the boiling gas heat exchanger module, the separated circulating water is conveyed to the single-pipe circulation pipe network, underground indirect multi-medium combination heat exchange is adopted, and the geothermal utilization efficiency and the system water supply stability are improved.)

1. The utility model provides a deep closed geothermal energy heating system which characterized in that: the system comprises an underground heat exchanger module, a boiling gas heat exchanger module, a single-pipe circulating pipe network, a multi-stage user side, a generator set and a circulating pump set;

the boiling gas heat exchanger module (4) is used for sending a heat exchange medium into the ground, conducting heat exchange through the ground and then guiding the heat exchange medium to be input into the input end of the underground heat exchanger module;

the underground heat exchanger module is used for carrying out secondary heat exchange on the heat exchange medium and circulating water after heat exchange, pumping the circulating water to a single-pipe circulating pipe network, and carrying out step-by-step conveying on the circulating water to a multi-stage user side through the single-pipe circulating pipe network, wherein the single-pipe circulating pipe network inputs return water formed after the circulating water is used by the multi-stage user side to the underground heat exchanger module;

the generator set is connected into the single-pipe circulation pipe network in a parallel connection mode with the multistage user side, the functions of a heat exchange medium pumped into the generator set by the underground heat exchanger module and circulating water are separated, the separated heat exchange medium is sent to the input end of the boiling gas heat exchanger module (4), and the separated circulating water is conveyed to the single-pipe circulation pipe network;

and the circulating pump group is arranged at the joint of the output end of the underground heat exchanger module and the single-pipe circulating pipe network, and on the single-pipe circulating pipe network at the output end of the multistage user side, and is used for entering circulating water for pumping the multistage user side step by step.

2. A medium depth closed geothermal energy heating system according to claim 1, wherein: the heat supply system also comprises a host control module and an internal pressure balancing module (3), the internal pressure balancing module is used for connecting the boiling gas heat exchanger module (4) and the input end of each level of users at the multi-level user end, and collects the status data of the boiling gas heat exchanger module (4) and the input end of each level of user at the multi-level user end, and sends the state data to the host control module, the generator set, the circulating pump set and the internal pressure balancing module are connected with the host control module, the host control module actively collects the state data of the generator set and the circulating pump set, and performs system load coefficient coupling on the analysis results of the state data of the generator set and the circulating pump set, and performing synchronous correction on the state data of the inner balance module to obtain the current optimal demand load of the system, and determining the number of the units of the circulating pump group according to the current optimal demand load of the system.

3. A medium depth closed geothermal energy heating system according to claim 1 or 2, wherein: the underground heat exchanger module comprises a coaxial sleeve underground heat exchanger main body (1) and a heat collection mechanism (2) arranged outside the coaxial sleeve underground heat exchanger main body (1), wherein the heat collection mechanism (2) comprises a ring-type unit (201), an expansion cavity pipe (202), a heat insulation cavity pipe (203) and a plurality of heat exchange pipes (204) which are arranged outside the coaxial sleeve underground heat exchanger main body (1) in an annular array mode, the expansion cavity pipe (202) is arranged at the bottom of the coaxial sleeve underground heat exchanger main body (1), the plurality of heat exchange pipes (204) are connected with the expansion cavity pipe (202) in a sealing mode, the part, extending out of the ground, of the plurality of heat exchange pipes (204) is connected with the heat insulation cavity pipe (203) in a sealing mode, the output end of the heat insulation cavity pipe (203) is connected with a pipeline at the joint of the single-pipe circulation pipe network and the underground heat exchanger module, and the heat collection mechanism (2) in Pumping a heat exchange medium into the coaxial sleeve underground heat exchanger main body; the underground heat exchange medium input by the boiling gas heat exchanger module permeates to the expansion cavity pipe (202) through a rock gap.

4. A medium depth closed geothermal energy heating system according to claim 3, wherein: the internal pressure balancing module (3) comprises a pressure pipeline (301) which is connected with the heat insulation cavity pipe (203) through a multi-way valve, the other end of the pressure pipeline (301) is connected with a single-pipe circulating pipe network of the input end of each stage of users at the multistage user side, and a sliding sealing plug (302) is arranged inside the pressure pipeline (301).

5. A medium depth closed geothermal energy heating system according to claim 3, wherein: boil gas heat exchanger module (4) and include pipeline main part (401) and set up and be used for in pipeline main part (401) inner tube (402) to the defeated gas of rock stratum cavity of the bottom of pipeline main part (401), sliding sleeve is equipped with sealed float post (403) on inner tube (402).

6. A medium depth closed geothermal energy heating system according to claim 2, wherein: the host control module is combined with a host group control technology based on COP optimization, a heat pump host optimization control technology and a mathematical model control technology, system load coefficient coupling and correction are carried out on the monitoring and execution results of the generator set, the circulating pump set and the inner balance module according to the actual load capacity and weather condition of each level of users at the multi-level user end and the system load at the next moment according to the historical system load and the outdoor temperature condition of the day.

7. A method of designing a closed geothermal energy heating system in the middle-deep layer according to any one of claims 1-6, characterised in that: the method specifically comprises the following steps:

s100, according to the topographic features, stratum and lithologic features and structural features of a to-be-developed area, determining main heat storage types, distribution, burying conditions, ground temperature features, rock-soil body heat conductivity, construction site engineering geological conditions, geological disaster distribution features and hydrogeological features, designing hole sites, hole depths, hole structures and hole intervals of geothermal wells of the underground heat exchanger module and the boiling gas heat exchanger module, and excavating holes of the underground heat exchanger, heat exchange tubes of the heat collection mechanism and the geothermal wells of the boiling gas heat exchanger;

s200, embedding the underground heat exchanger module and the boiling gas heat exchanger module in corresponding geothermal wells, connecting and laying a single-pipe circulating pipe network, establishing an underground deep layer heat exchange model, a boiling gas heat exchange efficiency model, a multi-stage user side water system model, a circulating pump module and a ground source heat exchange system hydraulic model, obtaining theoretical data of each model through experiments, and designing the boiling gas heat exchanger module and the underground heat exchanger module according to the theoretical data of each model.

S300, laying a single-pipe circulation pipe network of the multistage user side according to theoretical data, and connecting the multistage user side, the generator set and the circulation pump set into the single-pipe circulation pipe network.

8. The design method of a medium-deep closed geothermal energy heating system according to claim 7, wherein the underground deep heat exchange model is used for carrying out heat transfer analysis on geothermal wells of the underground heat exchanger module and the boiling gas heat exchanger module by constructing a heat transfer model of the fluid and the heat exchange gas input into the casing and constructing an extraporous rock soil body heat transfer model.

9. The design method of a medium-deep closed geothermal energy heating system according to claim 7, wherein in S100, the specific design method of the geothermal well of the boiling gas heat exchanger module and the heat collecting mechanism comprises the following steps:

s101, arranging a plurality of geothermal wells of pipeline main bodies of the boiling gas heat exchanger modules and geothermal wells of heat exchange pipes of a heat collection mechanism in the excavated geothermal wells of the underground heat exchanger modules according to the heat storage type and geothermal characteristics of rock strata and the heat conductivity of rock-soil bodies;

s102, crushing rock strata which vibrate oppositely at the same horizontal position at the bottom of a geothermal well of a heat exchange tube of the heat collection mechanism and the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism to form rock stratum heat exchange gaps between the geothermal well of the heat exchange tube of the heat collection mechanism and the geothermal well of the heat exchange tube of the heat collection mechanism;

s103, arranging a heat exchange cavity with the height higher than the rock stratum heat exchange gap at the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism and the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism, embedding the expansion cavity tube and the tail end of the pipeline main body at the top of the heat exchange cavity, and then backfilling rock soil.

Technical Field

The invention relates to the technical field of geothermal energy heat supply, in particular to a middle-deep closed geothermal energy heat supply system and a design method thereof.

Background

Research and development of key technologies for supplying heat by using intermediate-deep geothermal energy become research hotspots of some scientific research institutes in China, and the future development prospect is very wide with the support of national and relevant provincial policies. At present, some commercial buildings and residential buildings in Shaanxi, Hebei, Shanxi, Henan and the like adopt a middle-deep geothermal energy heating technology to realize winter heating, and the technology is still blank in the Withania tabacum region. Due to the disadvantages of initial investment, adjusting performance and the like, dependence on geological conditions and uncertainty on the influence of the surrounding environment, the utilization of the geothermal energy in the middle and deep layers is still in the starting stage at present.

In 2019, a temperature measuring hole DRZK01 with the thickness of 2000 m is constructed in the Futai Shanyuan, the highest temperature is disclosed to be 126.8 ℃, a high-temperature section with the thickness of nearly kilometers (the temperature is about 120 ℃ from 897 m to 1809 m) exists, and the potential of deep geothermal resources is more prominent in domestic similar geothermal resources. Through related test tests, the water-rich property of the temperature measuring well region is weak, and the requirement on a medium-deep layer heat exchange system is urgent.

The common middle-deep geothermal energy heat supply technology mainly comprises the following steps: a middle-deep hydrothermal type heat supply technology, a middle-deep closed geothermal heat supply technology, a middle-deep geothermal energy heat pipe heat supply technology, a waste oil well modified geothermal well heat supply technology, an enhanced geothermal heat supply technology and the like.

At present, hydrothermal heat supply is mainly used for medium-deep geothermal energy development, but a series of ecological environment problems exist, namely, utilized geothermal water cannot be recharged or recharged, the water level of a geothermal well is continuously reduced, and even geological disasters are caused. The geothermal water after being utilized contains fluorine, heavy metals and other harmful elements, and has higher temperature, and the direct discharge not only can pollute the quality of surface water. Practice shows that 'water extraction and heat extraction' do not meet continuous development, and although recharge has certain feasibility, the recharge efficiency is low, the decay is fast, the cost is high, and the recharge technology is difficult to break through in a short period. The existing hydrothermal geothermal well is limited to production, production forbidding and shut-down under the influence of policies, and the approval of the new hydrothermal geothermal well is strictly controlled.

Disclosure of Invention

The invention aims to provide a middle-deep layer closed geothermal energy heating system and a design method thereof, and aims to solve the problem that the existing middle-deep layer geothermal energy development is limited by regions and ecology.

In order to solve the technical problems, the invention specifically provides the following technical scheme:

a middle-deep layer closed geothermal energy heat supply system comprises an underground heat exchanger module, a boiling gas heat exchanger module, a single-pipe circulating pipe network, a multi-stage user side, a generator set and a circulating pump set;

the boiling gas heat exchanger module is used for sending a heat exchange medium into the ground, conducting heat exchange through the ground and then guiding the heat exchange medium to be input into the input end of the underground heat exchanger module;

the underground heat exchanger module is used for carrying out secondary heat exchange on the heat exchange medium and circulating water after heat exchange, pumping the circulating water to a single-pipe circulating pipe network, and carrying out step-by-step conveying on the circulating water to a multi-stage user side through the single-pipe circulating pipe network, wherein the single-pipe circulating pipe network inputs return water formed after the circulating water is used by the multi-stage user side to the underground heat exchanger module;

the generator set is connected into the single-pipe circulation pipe network in a parallel connection mode with the multistage user side, the functions of a heat exchange medium pumped into the generator set by the underground heat exchanger module and circulating water are separated, the separated heat exchange medium is sent to the input end of the boiling gas heat exchanger module, and the separated circulating water is conveyed to the single-pipe circulation pipe network;

and the circulating pump group is arranged at the joint of the output end of the underground heat exchanger module and the single-pipe circulating pipe network, and on the single-pipe circulating pipe network at the output end of the multistage user side, and is used for entering circulating water for pumping the multistage user side step by step.

In a preferable scheme of the invention, the heating system further comprises a host control module and an internal pressure balancing module, the internal pressure balancing module is used for connecting the boiling gas heat exchanger module and the input end of each stage of user of the multi-stage user end, and collecting state data of the boiling gas heat exchanger module and the input end of each stage of the multi-stage user end, and sends the state data to the host control module, the generator set, the circulating pump set and the internal pressure balancing module are connected with the host control module, the host control module actively collects the state data of the generator set and the circulating pump set, and performs system load coefficient coupling on the analysis results of the state data of the generator set and the circulating pump set, and performing synchronous correction on the state data of the inner balance module to obtain the current optimal demand load of the system, and determining the number of the units of the circulating pump group according to the current optimal demand load of the system.

As a preferable scheme of the invention, the underground heat exchanger module comprises a coaxial sleeve underground heat exchanger main body and a heat collecting mechanism arranged outside the coaxial sleeve underground heat exchanger main body, the heat collection mechanism comprises an annular unit, an expansion cavity pipe, a heat insulation cavity pipe and a plurality of heat exchange pipes arranged outside the coaxial sleeve underground heat exchanger body in an annular array manner, the expansion cavity pipe is arranged at the bottom of the coaxial sleeve underground heat exchanger body, the plurality of heat exchange tubes are hermetically connected with the expansion cavity tube, the part of the plurality of heat exchange tubes extending out of the ground is hermetically connected with the heat insulation cavity tube, the output end of the heat insulation cavity pipe is connected with a pipeline at the joint of the single pipe circulation pipe network and the underground heat exchanger module, pumping the heat exchange medium in the heat insulation cavity pipe into the underground heat exchanger main body through a ring type unit connected to the heat insulation cavity pipe; and the underground heat exchange medium input by the boiling gas heat exchanger module permeates to the expansion cavity pipe through the rock gap.

As a preferable scheme of the present invention, the internal pressure balancing module includes a pressure pipeline connected to the adiabatic cavity pipe through a multi-way valve, the other end of the pressure pipeline is connected to a single-pipe circulation pipe network at the input end of each stage of the user at the multi-stage user end, and a sliding sealing plug is disposed inside the pressure pipeline.

As a preferable scheme of the present invention, the boiling gas heat exchanger module includes a pipeline main body and an inner tube disposed in the pipeline main body and configured to transport gas to a soil layer cavity at the bottom of the pipeline main body, and a sealing float column is slidably sleeved on the inner tube.

As a preferred scheme of the present invention, the host control module combines a host group control technology based on COP optimization, a heat pump host optimization control and a mathematical model control technology, predicts a system load at the next moment according to an actual load capacity and a weather condition of each level of users at a multi-level user end and according to a historical system load and an outdoor temperature condition of the day, and performs system load coefficient coupling and correction on results monitored and executed by the generator set, the circulating pump set and the inner balance module.

The invention provides a design method of a middle-deep closed geothermal energy heating system, which specifically comprises the following steps:

s100, according to the topographic features, stratum and lithologic features and structural features of a to-be-developed area, determining main heat storage types, distribution, burying conditions, ground temperature features, rock-soil body heat conductivity, construction site engineering geological conditions, geological disaster distribution features and hydrogeological features, designing hole sites, hole depths, hole structures and hole intervals of geothermal wells of the underground heat exchanger module and the boiling gas heat exchanger module, and excavating holes of the underground heat exchanger, heat exchange tubes of the heat collection mechanism and the geothermal wells of the boiling gas heat exchanger;

s200, embedding the underground heat exchanger module and the boiling gas heat exchanger module in corresponding geothermal wells, connecting and laying a single-pipe circulating pipe network, establishing an underground deep layer heat exchange model, a boiling gas heat exchange efficiency model, a multi-stage user side water system model, a circulating pump module and a ground source heat exchange system hydraulic model, obtaining theoretical data of each model through experiments, and designing the boiling gas heat exchanger module and the underground heat exchanger module according to the theoretical data of each model.

S300, laying the single-pipe circulation pipe network of the multistage user side according to the theoretical data, and connecting the multistage user side, the generator set and the circulation pump set into the single-pipe circulation pipe network.

As a preferable aspect of the present invention, the deep underground heat exchange model performs heat transfer analysis in the heat source well by constructing a heat transfer model of the fluid and the heat exchange gas introduced into the casing and constructing a rock-soil heat transfer model outside the hole to perform heat transfer analysis outside the heat source well.

As a preferable scheme of the present invention, in S100, a specific design method of the geothermal well of the boiling gas heat exchanger module and the heat collecting mechanism includes:

s101, arranging a plurality of geothermal wells of pipeline main bodies of the boiling gas heat exchanger modules and geothermal wells of heat exchange pipes of a heat collection mechanism in the excavated geothermal wells of the underground heat exchanger modules according to the heat storage type and geothermal characteristics of rock strata and the heat conductivity of rock-soil bodies;

s102, crushing rock strata which vibrate oppositely at the same horizontal position at the bottom of a geothermal well of a heat exchange tube of the heat collection mechanism and the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism to form rock stratum heat exchange gaps between the geothermal well of the heat exchange tube of the heat collection mechanism and the geothermal well of the heat exchange tube of the heat collection mechanism;

s103, arranging a heat exchange cavity with the height higher than the rock stratum heat exchange gap at the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism and the bottom of the geothermal well of the heat exchange tube of the heat collection mechanism, embedding the expansion cavity tube and the tail end of the pipeline main body at the top of the heat exchange cavity, and then backfilling rock soil.

Compared with the prior art, the invention has the following beneficial effects:

the technology can be used for drilling holes nearby around a building and building a machine room on the spot in a basement, flexibly meets the heating requirement, realizes accurate matching of supply and demand by using a distributed system, realizes distributed heat supply, is particularly suitable for areas where municipal heat supply networks are difficult to reach, and avoids the serious pollution problem of distributed coal-fired boilers.

The underground indirect heat exchange is adopted to realize that 'heat is taken and water is not taken'; underground water resources are not polluted, and the problems of underground water emptying, tail water thermal pollution or high-pressure recharging are avoided; and no waste gas, waste water or waste residue is discharged, so that the method belongs to a high-cleanness, zero-pollution and zero-emission green energy technology, and is typical of new energy utilization.

Free terrestrial heat is utilized, a high-efficiency high-temperature heat pump technology is combined, and meanwhile, an outdoor pipe network does not need to be laid, so that the conveying energy consumption and the pipe network loss are reduced, and the energy efficiency is high.

The electric energy is utilized to drive the heat pump unit, geothermal resources stored in the underground rock stratum are extracted for heating, and the heat pump is stable and reliable in heating of the buried pipe of the intermediate-deep geothermal energy due to the fact that the geothermal resources are large in reserve and good in stability.

The heat pump system has the advantages that the occupied area is small, the limitation condition is few, the application range is wide, and compared with a soil source heat pump, the heat taking amount of a single underground heat exchanger of the middle-deep geothermal buried pipe heat pump system is large, so that the number of the underground heat exchangers and the occupied area thereof can be greatly reduced; is not limited by meteorological conditions, geothermal geological conditions and the like, and has wide application range.

The process flow is simple, the requirement on the water temperature is loose, the water temperature can be used for heating from 20-180 ℃, and the heat loss in the heating process is small.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

FIG. 1 is a block diagram that schematically illustrates a system architecture according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a boiling gas heat exchanger module according to an embodiment of the present invention.

Reference numbers in the figures:

1-a coaxial casing underground heat exchanger body; 2-a heat collecting mechanism; 3-an internal pressure balancing module; 4-a boiling gas heat exchanger module;

201-ring type machine set; 202-an inflation lumen; 203-an insulated lumen tube; 204-heat exchange tube; 301-pressure line; 302-sliding sealing plug; 401-a pipe body; 402-an inner tube; 403-sealing the buoyant column.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in fig. 1 and 2, the invention provides a medium-deep closed geothermal energy heating system, which comprises an underground heat exchanger module, a boiling gas heat exchanger module 4, a single-pipe circulating pipe network, a multi-stage user terminal, a generator set and a circulating pump set;

the boiling gas heat exchanger module 4 is used for sending a heat exchange medium into the ground, conducting heat exchange through the ground and then guiding the heat exchange medium to be input into the input end of the underground heat exchanger module;

the underground heat exchanger module is used for carrying out secondary heat exchange on the heat exchange medium and circulating water after heat exchange, pumping the circulating water to the single-pipe circulating pipe network, and carrying out step-by-step conveying on the multi-stage user side through the single-pipe circulating pipe network;

the generator set is connected into the single-pipe circulation pipe network in parallel with the multistage user side, the functions of heat exchange media pumped into the generator set by the underground heat exchanger module and circulating water are separated, the separated heat exchange media are sent to the input end of the boiling gas heat exchanger module 4, and the separated circulating water is conveyed to the single-pipe circulation pipe network;

and the circulating pump group is arranged at the joint of the output end of the underground heat exchanger module and the single-pipe circulating pipe network, is arranged on the single-pipe circulating pipe network at the output end of the multistage user side, and is used for entering circulating water for pumping the multistage user side step by step.

Considering that hydrothermal geothermal resources are limited by regions and limited by underground water development rights, other geothermal energy heating technologies have various defects and are not applied much at present, so that the technology is particularly suitable for regions which are difficult to reach by municipal heat networks, the problem of serious pollution of distributed coal-fired boilers is avoided, and the defect that clean energy sources such as solar energy, wind energy and the like are limited by meteorological conditions is overcome.

Further, the heat exchange medium in the present invention may be a liquid, such as secondary return water on the user side or a gas, such as carbon dioxide.

Furthermore, the heat exchange medium and the liquid are combined for heat exchange, and the gas has higher heat exchange efficiency and stronger diffusivity in a rock stratum compared with the liquid, so that the gas can supplement and exchange heat with the traditional liquid circulating water, and the circulating water is used by the multistage user side and then is input into the underground heat exchanger module through the single-pipe circulating pipe network, so that the heat exchange is carried out.

Furthermore, through the mode of letting in heat transfer medium to the input of underground heat exchanger module and carrying out the heat transfer, can increase the pressure in the underground heat exchanger main part to this reduces the high power operating duration of circulating pump, and because in the practical application in-process, the circulating water that multistage user end input underground heat exchanger module is not stable, consequently, make then need continuous work quantity and the operating power who adjusts the circulating pump group, realize the dynamic balance of overall system, and in this application, then can come the dynamic balance of the circulating water flow of indirect control entire system through the flow of control injection heat transfer medium.

Further, the generator set of the invention adopts an organic Rankine generator set, and an evaporator is arranged at the front end of the single-pipe circulation pipe network input generator set and is used for separating water from gas.

Furthermore, the preferable heat exchange medium in the invention is carbon dioxide, in the invention, the carbon dioxide is introduced into rock gaps of the rock stratum through the boiling gas heat exchanger module, and the chemical reaction of the carbon dioxide can be carried out through the rock stratum under the condition of high temperature, so that the carbon capture and fixation are carried out.

The heating system further comprises a host control module and an internal pressure balancing module 3, the internal pressure balancing module 3 is used for connecting the input ends of the boiling gas heat exchanger module 4 and each level of users at the multistage user sides, collecting state data of the input ends of the boiling gas heat exchanger module 4 and each level of users at the multistage user sides, and sending the state data to the host control module, the generator set, the circulating pump set and the internal pressure balancing module 3 are connected with the host control module, the host control module actively collects the state data of the generator set and the circulating pump set, and carries out system load coefficient coupling on the analysis results of the state data of the generator set and the circulating pump set, the current optimal demand load of the system is obtained by synchronously correcting the state data of the internal balancing module, and the number of sets of the circulating pump set is determined according.

In order to further improve the operating efficiency of the system, the system adopts related equipment to carry out optimization control based on load prediction, and the optimization control mainly comprises three parts, namely a pipe network energy balance distribution technology, a circulating pump optimization control technology, a host optimization control technology and the like.

(1) Pipe network energy balance distribution technology

Due to different use functions and areas of each load area, resistance difference exists between input ends of each stage of users at the multi-stage user ends, so that the actually required flow and the supplied flow of each loop are inconsistent or no flow exists at the farthest end of the worst loop under the condition of variable flow.

The energy of a circulating pump heating system is unbalanced, heat distribution is uneven, heat supply quality is poor, heat supply is inevitably increased in order to take account of unfavorable regional heat supply effects, a heat pump host and a water pump do work in vain, and great energy waste is caused.

Through studying the energy balance distribution technology of the input end of each level user of the multi-level user side, the system load pre-judgment intelligent adjusting system formed by combining the host control module carries out energy balance automatic distribution on favorable and unfavorable load areas of the system, the efficiency is improved by intelligent and dynamic means, the overall comfort of heat supply is improved, and energy-saving optimization can be effectively realized.

(2) Circulating pump set optimization control technology

The method is characterized in that the load size is predicted according to the current load, the environment temperature, the load curve and the like detected by a host control module, on the basis of the balanced distribution control of the cold energy in each load area, a fuzzy pre-judgment control technology, a circulating water pump energy-saving control calculation model and a pump set optimal control technology are combined, so that the heat supply and demand are balanced, the heat source side water flow and the load side flow are balanced, and the system energy consumption is combined and compared, the lowest comprehensive energy consumption is ensured (namely, the main control module energy consumption is increased and the water pump energy consumption is reduced to be dominant after the water amount is reduced), and the self-adaptive variable flow regulation control of a circulating pump set is realized.

(3) Host optimization control technique

On the basis of the area cold quantity balanced distribution control and the circulating pump variable flow control, a host group control technology based on COP optimization and a heat pump host optimization control mathematical model control technology are combined. And predicting the air conditioning load at the next moment according to the actual load quantity of the tail end, the weather condition (temperature and humidity) and the combination of the historical air conditioning load and the outdoor temperature condition of the day.

The three are corrected according to a certain mode to obtain the current optimal demand load of the system. And determining the number of the running refrigerating units according to the current optimal demand load of the system. The heat pump unit is matched and optimized to control, and the real-time load at the tail end is matched with the heat provided by the heat source. The problem of system energy consumption waste is solved, and host efficiency is improved.

The underground heat exchanger module comprises a coaxial sleeve underground heat exchanger main body 1 and a heat collection mechanism 2 arranged outside the coaxial sleeve underground heat exchanger main body 1, wherein the heat collection mechanism 2 comprises a ring unit 201, an expansion cavity pipe 202, a heat insulation cavity pipe 203 and a plurality of heat exchange pipes 204 which are arrayed outside the coaxial sleeve underground heat exchanger main body 1 in an annular mode, the expansion cavity pipe 202 is arranged at the bottom of the coaxial sleeve underground heat exchanger main body 1, the heat exchange pipes 204 are connected with the expansion cavity pipe 202 in a sealing mode, the parts of the heat exchange pipes 204 extending out of the ground are connected with the heat insulation cavity pipe 203 in a sealing mode, the output end of the heat insulation cavity pipe 203 is connected with a pipeline at the joint of a single-pipe circulation pipe network and the underground heat exchanger module, and heat exchange media in the heat insulation; the underground heat exchange medium input by the boiling gas heat exchanger module 4 permeates to the expansion cavity pipe 202 through the rock gap.

The internal pressure balancing module 3 comprises a pressure pipeline 301 connected with the heat insulation cavity pipe 203 through a multi-way valve, the other end of the pressure pipeline 301 is connected with a single-pipe circulation pipe network at the input end of each stage of users at the multistage user end, and a sliding sealing plug 302 is arranged inside the pressure pipeline 301.

The boiling gas heat exchanger module 4 comprises a pipeline main body 401 and an inner pipe 402 arranged in the pipeline main body 401 and used for conveying gas to a soil layer cavity at the bottom of the pipeline main body 401, wherein a sealing floater 403 is slidably sleeved on the inner pipe 402.

The host control module is combined with a host group control technology based on COP optimization, a heat pump host optimization control technology and a mathematical model control technology, system load coefficient coupling and correction are carried out according to the actual load capacity and weather condition of each level of users at the multi-level user end and the system load at the next moment according to the historical system load and the outdoor temperature condition of the same day, and the monitoring and execution results of the generator set, the circulating pump set and the inner balance module are achieved.

The invention provides a design method of a middle-deep closed geothermal energy heating system, which specifically comprises the following steps:

s100, according to the topographic features, stratum and lithologic features and structural features of a to-be-developed area, determining main heat storage types, distribution, burying conditions, ground temperature features, rock-soil body heat conductivity, construction site engineering geological conditions, geological disaster distribution features and hydrogeological features, designing hole sites, hole depths, hole structures and hole intervals of geothermal wells of the underground heat exchanger module and the boiling gas heat exchanger module 4, and excavating holes of the underground heat exchanger, heat exchange tubes 204 of the heat collection mechanism 2 and the geothermal wells of the boiling gas heat exchanger;

s200, burying the underground heat exchanger module and the boiling gas heat exchanger module 4 in corresponding geothermal wells, connecting and laying a single-pipe circulating pipe network, establishing an underground deep layer heat exchange model, a boiling gas heat exchange efficiency model, a multi-stage user side water system model, a circulating pump module and a ground source heat exchange system hydraulic model, obtaining theoretical data of each model through experiments, and designing the boiling gas heat exchanger module 4 and the underground heat exchanger module according to the theoretical data of each model.

S300, laying a single-pipe circulation pipe network of the multistage user side according to theoretical data, and connecting the multistage user side, the generator set and the circulation pump set into the single-pipe circulation pipe network.

In order to know the change rule of the heat exchange capacity of the underground heat exchanger and match the heat exchange capacity of the middle-deep underground heat exchanger with the heat demand of a user, so that the structural size of the middle-deep heat exchanger is further optimized, the initial investment of a system is reduced, a numerical simulation research needs to be carried out on the middle-deep geothermal heat-buried pipe heat pump heat supply system, and a whole set of design method of the middle-deep geothermal heat-buried pipe heat pump heat supply system including the design method of the middle-deep underground heat exchanger is formed.

The model of the heat supply system of the heat pump of the buried pipe of the middle-deep geothermal energy is divided into six parts: the system comprises an underground deep layer heat exchange model, a heat supply demand side model, a user side water system model, a circulating pump unit model, a ground source heat exchange system hydraulic model and a boiling gas heat exchange module.

And the underground deep layer heat exchange model is used for carrying out heat transfer analysis in the heat source well by constructing a heat transfer model of fluid in the sleeve, and is used for carrying out heat transfer analysis outside the heat source well by constructing a rock soil body heat transfer model outside the hole. After the heat transfer model is built inside and outside the heat source well, the heat transfer model coupled inside and outside the heat source well is built through the sleeve boundary according to the energy balance equation, the heat transfer differential equation and the heat transfer model. And forming an underground deep layer heat exchange model which is the basis for designing the underground heat exchanger.

The model of the heat supply demand side is established by combining meteorological data of the building location according to detailed information of the building envelope (including parameters such as height, thickness, heat transfer coefficient, specific heat capacity and density of building materials used for walls, windows and floor slabs), a staff work and rest time table, an equipment work time table, a time-by-time change curve of the number of staff, lamp and equipment power and the like. And obtaining the hourly heat demand of the heat supply demand side in the heating season through model analysis.

And a user side water system model is established, a user side circulating pump model, a heat pump condenser water side pipeline model, a user end model and a user side pipeline model are established to form a whole set of user side water system model, and the transmission rule between the user side heat demand and the heat pump side heat production is researched. Therefore, on the basis of ensuring that the heat demand of the user side is matched with the heat production of the heat pump side, a method for reducing the transmission and distribution energy consumption of the water system of the user side is researched.

The method comprises the steps of establishing a heat pump evaporator, a condenser heat exchange model, a compressor model and a throttle valve model, and researching the relation between fluid parameters (inlet and outlet temperature and flow) on the evaporator side, fluid parameters (inlet and outlet temperature and flow) on the condenser side and system performance and the characteristics of the system under partial load. Through the circulating pump unit model, the running parameters matched with the heat exchange capacity of the underground heat exchanger are searched, so that the performance of the heat pump unit is improved.

The hydraulic model of the ground source heat exchange system relates an underground heat exchanger model and a circulating pump unit model. The heat pump evaporator side pipeline model mainly comprises an underground heat exchanger pipeline model, an above-ground pipeline network model and a heat pump evaporator side pipeline model.

In S100, the specific design method of the geothermal well of the boiling gas heat exchanger module 4 and the heat collecting mechanism 2 includes:

s101, arranging a plurality of geothermal wells of the pipeline main body 401 of the boiling gas heat exchanger module 4 and geothermal wells of the heat exchange pipes 204 of the heat collection mechanism 2 in the excavated geothermal wells of the underground heat exchanger modules according to the heat storage type and geothermal characteristics of rock strata and the heat conductivity of rock-soil bodies;

s102, crushing rock strata which vibrate oppositely at the same horizontal position at the bottom of the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2 and the bottom of the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2 to form rock stratum heat exchange gaps between the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2 and the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2;

s103, arranging a heat exchange cavity with the height higher than the rock stratum heat exchange gap at the bottom of the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2 and the bottom of the geothermal well of the heat exchange tube 204 of the heat collection mechanism 2, embedding the expansion cavity tube 202 and the tail end of the pipeline main body 401 at the top of the heat exchange cavity, and then backfilling rock soil.

In S100, determining the parameters of the geothermal well specifically includes:

determining the pipe diameter of the drilling sleeve, including the diameter and the wall thickness of the inner pipe 402 and the outer pipe, and determining the material of the inner pipe 402 and the outer pipe of the drilling sleeve;

determining the flow of the deep-hole ground heat exchanger, and determining the flow direction of circulating water in a sleeve heat exchanger connected with the deep-hole ground heat exchanger;

theoretically calculating and determining the heat taking capacity of the deep-hole ground heat exchanger;

and (3) researching the influence of different drilling depths on the heat extraction of the system, and burying the deep-hole ground heat exchanger to determine the optimal depth.

The drilling process of the geothermal well specifically comprises the steps of determining the heat taking capacity of the geothermal well (group) by taking heat supply as a target in geothermal geological exploration, finding out the topographic features, stratum and lithological features and structural features of a to-be-developed section, and determining the main heat storage type, distribution, burying conditions, ground temperature features, rock-soil body heat conductivity, construction site engineering geological conditions, geological disaster distribution features and hydrogeological features, so that a basis is provided for reasonably designing the hole position, the hole depth, the hole structure and the hole spacing of the geothermal well (group).

The method comprises the following four parts of geological survey, geothermal geological survey, rock and soil test and in-situ test and geothermal resource evaluation:

(1) geological survey

The method comprises the following aspects:

1) investigation of lithology of stratum

Analyzing and supplementing and investigating stratum sequence, geological age, cause type, lithology and lithofacies characteristics, occurrence, thickness and contact relation of the to-be-developed section, and dividing the structure of the heat storage layer system.

2) Investigation of geological structures

Combining the means of remote sensing interpretation, geophysics, radon gas measurement and the like, analyzing the unit parts, the regional structure and the new structure motion characteristics of the large-area structure of the to-be-developed field, and basically ascertaining the type, the property, the occurrence, the scale, the distribution, the formation era, the activity and the control effect on the geothermal conduction.

3) Investigation of geological problems in poor engineering

And checking whether the to-be-developed field has unfavorable engineering geology problems of ground settlement, ground cracks, collapsible loess, sandy soil liquefaction, landslide, collapse, debris flow and the like.

4) Hydrogeological condition survey

The distribution characteristics of local groundwater aquifers (including shallow groundwater aquifers and deep geothermal water intake layer sections) with water supply significance and the distribution and protection area division conditions of the water supply source areas are investigated.

(2) Geothermal geological survey

The method comprises the following aspects:

1) data gathering and analysis

And comprehensively collecting a regional geothermal geological research report, an interference-free drilling hole report or a hydrothermal geothermal well hole forming report of adjacent sections and similar conditions, and performing comprehensive analysis.

2) Survey of heat storage structure

And analyzing the heat storage geological structure of the to-be-developed region by combining the geological condition investigation result, and finding out the depth of the constant temperature zone, the distribution of the heat storage cover layer, the lithology, the thickness, the burial depth, the distribution, the interrelation and the boundary conditions of each heat storage.

3) Survey of earth temperature gradient

And analyzing the earth temperature gradient and the earth temperature change rules of different depths by combining the measures of thermal infrared remote sensing interpretation, superficial temperature measurement, geophysical exploration, radon gas measurement and the like, and finding out the temperature of the thermal reservoir of the region to be developed and the characteristics of the earth temperature field.

4) Heat storage parameter survey

And analyzing geothermal well parameters of each thermal storage of the to-be-developed section according to adjacent sections and similar conditions by combining geological condition investigation results, and determining parameters such as density, specific heat capacity, heat conduction coefficient and the like of each thermal storage.

(3) Rock and soil testing

And selecting 1 drilling hole as a exploring and mining combined hole to perform rock-soil test and in-situ test.

1) Sample collection and testing

And (3) taking 1-3 rock cores for each thermal reservoir of the exploration hole and exploration and mining combined hole heat taking section, and testing the density, porosity, heat conductivity coefficient, heat diffusion coefficient, specific heat capacity and the like of a rock core sample.

2) Geophysical survey

And detecting and mining the full-hole by combining with the hole object detection hole, wherein hole detection parameters comprise apparent resistivity, natural potential and drilling temperature at different depths, and measurement data such as natural gamma, formation sound wave speed, hole diameter, porosity, magnetic susceptibility, energy spectrum and the like can be selected when conditions allow.

(4) Geothermal resource evaluation

And in combination with relevant specifications, the single-hole allowable exploitation amount calculates the single-hole recoverable resource amount according to the exploitation 100 years and the consumption of about 15% of geothermal energy storage, and the reasonable hole spacing is determined according to the fact that the single-hole allowable exploitation amount can meet the heat extraction requirement of the geothermal heat exchanger.

And (4) testing the heat taking capacity after the geothermal well is built, and obtaining parameters such as the temperature, the flow and the like of the heat medium at the inlet and the outlet of the geothermal well through the test. And drawing a relation curve of inlet and outlet temperature, flow and time. And evaluating the reasonable heat taking capability of the geothermal well.

The above embodiments are only exemplary embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present application and such modifications and equivalents should also be considered to be within the scope of the present application.