阅读说明：本技术 可持续利用的跨季节地热能开发系统 (Sustainable-utilization cross-season geothermal energy development system ) 是由 张金龙 李晶 王含 郑新 张迪 王绪伟 周杲昕 张小铮 孙雨潇 于 2019-02-25 设计创作，主要内容包括：本发明提出一种可持续利用的跨季节地热能开发系统,包括：地热井、井下外管、可切换地热井隔封、绝热套管、井下内管、多级板换、热泵、用户、循环水箱、可再生热源、梯级利用系统循环泵、跨季节不热系统循环泵、夏季供冷系统循环泵及多个阀门,其中,可切换地热井隔封设置在地热储层的低温区与高温区之间,通过对可切换地热井隔封进行切换,使可持续利用的跨季节地热能开发系统进入不同的能源开发模式。本发明应用范围广、长期运行经济性佳、环保效益显著,彻底解决地热单井供能小、长期使用热量衰减等问题,并提高了地热能利用的热源稳定性和经济最优性,在开发地热能的同时保护了地热资源的可持续性。(The invention provides a sustainable cross-season geothermal energy development system, which comprises: the system comprises a geothermal well, an underground outer pipe, a switchable geothermal well isolation seal, a heat insulation sleeve, an underground inner pipe, a multistage plate heat exchanger, a heat pump, a user, a circulating water tank, a renewable heat source, a cascade utilization system circulating pump, a cross-season unheated system circulating pump, a summer cooling system circulating pump and a plurality of valves, wherein the switchable geothermal well isolation seal is arranged between a low-temperature area and a high-temperature area of a geothermal reservoir, and the switchable geothermal well isolation seal is switched to enable the cross-season geothermal energy development system capable of being continuously utilized to enter different energy development modes. The invention has wide application range, good economy in long-term operation and obvious environmental protection benefit, thoroughly solves the problems of small energy supply of a geothermal single well, heat attenuation in long-term use and the like, improves the heat source stability and economic optimality of geothermal energy utilization, and protects the sustainability of geothermal resources while developing geothermal energy.)

1. A sustainable cross-season geothermal energy development system, comprising: a geothermal well, a downhole outer pipe, a switchable geothermal well isolation seal, a thermally insulating sleeve, a downhole inner pipe, a multistage plate exchanger, a heat pump, a user, a circulation water tank, a renewable heat source, a cascade utilization system circulation pump, a cross-season non-thermal system circulation pump, a summer cooling system circulation pump, and a plurality of valves through which the multistage plate exchanger, the heat pump, the user, the circulation water tank, the renewable heat source, the cascade utilization system circulation pump, the cross-season non-thermal system circulation pump, the summer cooling system circulation pump are selectively connected,

the switchable geothermal well insulation seal is arranged between a low-temperature area and a high-temperature area of a geothermal reservoir, and the switchable geothermal well insulation seal is switched, so that the sustainable cross-season geothermal energy development system enters different energy development modes.

2. A sustainable cross-season geothermal energy development system according to claim 1, wherein the different energy development modes comprise at least: a winter multi-energy complementary heat supply mode, a summer cold supply mode and a cross-season heat storage mode.

3. A sustainable cross-season geothermal energy exploitation system according to claim 2, wherein during winter the switchable geothermal well seal is open, creating a wellhead to bottom of the well path between the downhole outer pipe and the insulated casing, circulating water can circulate throughout the well; in summer, the switchable geothermal well is sealed and closed, the geothermal well is divided into an upper layer and a lower layer, and circulating water can only circulate in an area between the switchable geothermal well and a wellhead.

4. The sustainable cross-season geothermal energy development system according to claim 2 or 3, wherein in the winter multi-energy complementary heating mode, circulating water is injected into a heat exchange space formed between the underground outer pipe and the heat insulation sleeve by using the potential energy of the circulating water tank, geothermal reservoir heat is extracted through sufficient heat exchange, and the heat-exchanged hot water is sent to a multi-stage plate exchanger along the underground inner pipe and is supplied to users through the multi-stage plate exchanger and a heat pump exchanger.

5. The sustainable cross-season geothermal energy development system according to claim 4, wherein the multistage plate exchanger comprises at least a first stage plate exchanger and a second stage plate exchanger, tail water generated after primary side heat exchange of the first stage plate exchanger is heated by the renewable heat source, enters the second stage plate exchanger and the cascade utilization cycle of the heat pump after the supply water temperature is increased, and tail water generated after sufficient heat exchange of the second stage plate exchanger circulates to the circulating water tank and enters the geothermal well again for circulating heat exchange.

6. A sustainable cross-season geothermal energy development system according to claim 2 or 3, wherein in the summer cooling mode, a low temperature region of a geothermal reservoir is used as a cooling source of the user cooling cycle, the user heat is injected from the downhole inner pipe, flows through the switchable geothermal well barrier, exchanges heat between the heat insulation sleeve and the downhole outer pipe, and the exchanged cold water cools the user.

7. A sustainable cross-season geothermal energy development system according to claim 2 or claim 3, wherein in the cross-season heat storage mode the renewable heat source is injected from the downhole inner pipe, flows through the switchable geothermal well barrier, exchanges heat between the insulated casing and the downhole outer pipe, and exchanges heat to a geothermal reservoir low temperature zone.

8. The sustainable cross-season geothermal energy development system of claim 7, wherein the on-time and period of the cross-season heat storage mode may be determined according to a type of the renewable heat source.

9. The sustainable cross-season geothermal energy development system of claim 8, wherein a zone depth of the cross-season heat-stored coverage area is determined from a maximum heating temperature of the renewable heat source.

10. A sustainable cross-season geothermal energy development system according to claim 8 or claim 9, wherein the renewable heat source comprises at least one of solar energy, wind energy, biomass energy.

Technical Field

The invention relates to the technical field of energy, in particular to a sustainable cross-season geothermal energy development system.

Background

The sustainable utilization cross-season geothermal energy development technology is mainly applied to the geothermal energy development and utilization industry, including the fields of geothermal energy heating, refrigeration and the like, and the related fields of combination of geothermal energy and planting and breeding industry and the like.

Currently, geothermal energy exploitation and heat supply mainly utilize two forms of a twin well and a single well, and the single well is mainly used for heat exploitation without water, which is limited by local geothermal conditions, and the single well exploitation capability is directly related to the single well energy supply capability. At present, the measures for expanding the energy supply capacity of a single well mainly comprise conventional geothermal energy gradient utilization, peak-regulation type multi-energy complementation by utilizing equipment such as a gas boiler, an electric boiler and the like, wherein the geothermal energy gradient utilization and the peak-regulation type multi-energy complementation of the equipment such as the gas boiler, the electric boiler and the like need to increase the system investment and the equipment operation cost, and the economical efficiency is directly influenced.

The prior art provides a system for using a middle-deep layer undisturbed geosynthetic hole as a cold and heat source, which comprises a refrigeration outer pipe arranged in the geosynthetic hole, wherein a middle-layer pipe is arranged in the refrigeration outer pipe, a central pipe is arranged in the middle-layer pipe, the bottom end of the refrigeration outer pipe is positioned on the lower surface of a cold source region, the bottom end of the refrigeration outer pipe is connected with an outer connecting pipe, the bottom end of the middle-layer pipe is connected with the top end of a cold and heat converter, the bottom end of the cold and heat converter is connected with a heating heat exchange pipe through an inner connecting pipe, the central pipe penetrates through the bottom of the heating heat exchange pipe and is communicated with the bottom of the heating heat exchange pipe, the bottom end of the heating heat exchange pipe is connected with a stabilizing cone, the side surface of the cold and heat converter is provided with a flow outlet hole communicated with the refrigeration outer pipe, a sealing ring is arranged between the outer connecting pipe and the inner connecting pipe, the, one path is communicated with the water return port and the middle layer pipe, the other path is communicated with the refrigerating water outlet and the refrigerating outer pipe, and the other path is communicated with the heating water outlet and the central pipe, so that a cold source utilization loop of the water return port, the middle layer pipe, the cold-heat converter, the refrigerating outer pipe and the refrigerating water outlet is formed in summer, and a heat source utilization loop of the water return port, the middle layer pipe, the cold-heat converter, the inner connecting pipe, the heating heat exchange pipe, the central pipe and the heating water outlet is formed in. However, this system has the following disadvantages: the energy supply capacity of the system depends on local geothermal resources to a great extent, and the application range cannot be expanded; the ground temperature drops gradually in the energy supply process in winter, but heat is injected only for the soil layer in 0-1000 meters in summer, and long-term use will lead to that single-well energy supply ability declines year by year.

The prior art also provides a solar energy and geothermal energy auxiliary type centralized heating system, which comprises a heat source, an absorption heat pump, a heat user, a solar heat collector, a buried pipe, a plurality of circulating water pumps, various connecting pipelines and accessories, wherein a primary heat supply network high-temperature hot water from the heat source drives the absorption heat pump, a soil source is used as a low-level heat source of the absorption heat pump, an absorption heat pump evaporator is connected with the buried pipe, and a heat medium absorbs heat from soil and releases heat into the absorption heat pump evaporator; the solar heat collector is used as an auxiliary heat source of a heat supply system to supply heat jointly with the buried pipe in the heating period, and is used as a recharging heat source in the non-heating period so as to recover the temperature of soil around the buried pipe and maintain the balance of the heat energy of the soil; and the return water of the secondary heat supply network is heated by the absorption heat pump and then is sent to a heat user through the secondary heat supply network. However, this system has the following disadvantages: the system is mainly supplied with heat by a heat supply network, and the energy of geothermal energy and solar energy is only used as an auxiliary heat source and is not an energy supply source; the geothermal energy utilized by the system only relates to shallow buried heat pipes, cannot be popularized to a medium-deep geothermal energy utilization system, and does not fully utilize geothermal resources.

Disclosure of Invention

The present invention is directed to solving at least one of the above problems.

Therefore, the invention aims to provide a sustainable cross-season geothermal energy development system which is wide in application range, good in economy in long-term operation and remarkable in environmental protection benefit, thoroughly solves the problems of small energy supply of a geothermal single well, long-term use heat attenuation and the like, improves the heat source stability and economic optimality of geothermal energy utilization, and protects the sustainability of geothermal resources while developing geothermal energy.

In order to achieve the above object, an embodiment of the present invention proposes a sustainable cross-season geothermal energy development system, including: the system comprises a geothermal well, an underground outer pipe, a switchable geothermal well isolation seal, a heat insulation sleeve, an underground inner pipe, a multistage plate heat exchanger, a heat pump, a user, a circulating water tank, a renewable heat source, a cascade utilization system circulating pump, a cross-season unheated system circulating pump, a summer cooling system circulating pump and a plurality of valves, wherein the multistage plate heat exchanger, the heat pump, the user, the circulating water tank, the renewable heat source, the cascade utilization system circulating pump, the cross-season unheated system circulating pump and the summer cooling system circulating pump are selectively connected through the valves, the switchable geothermal well isolation seal is arranged between a low-temperature area and a high-temperature area of a geothermal reservoir, and the switchable geothermal well isolation seal is switched to enable the sustainable cross-season geothermal energy development system to enter different energy development modes.

In addition, the sustainable cross-season geothermal energy development system according to the above embodiment of the present invention may further have the following additional technical features:

in some examples, the different energy development modes include at least: a winter multi-energy complementary heat supply mode, a summer cold supply mode and a cross-season heat storage mode.

In some examples, during winter, the switchable geothermal well seal is opened, a passage from the wellhead to the bottom of the well is formed between the downhole outer pipe and the heat-insulating sleeve, and circulating water can circulate in the whole well; in summer, the switchable geothermal well is sealed and closed, the geothermal well is divided into an upper layer and a lower layer, and circulating water can only circulate in an area between the switchable geothermal well and a wellhead.

In some examples, in the winter multi-energy complementary heating mode, circulating water is injected into a heat exchange space formed between the underground outer pipe and the heat-insulating sleeve by using the potential energy of the circulating water tank, geothermal reservoir heat is extracted through sufficient heat exchange, and hot water after heat exchange is sent to a multi-stage plate for exchange along the underground inner pipe, and is supplied to users through the multi-stage plate for exchange and heat pump for exchange.

In some examples, the multistage plate exchanger at least comprises a first stage plate exchanger and a second stage plate exchanger, tail water after primary side heat exchange of the first stage plate exchanger is heated by the renewable heat source, after the supply water temperature is increased, in a cascade utilization cycle entering the second stage plate exchanger and the heat pump, the tail water after sufficient heat exchange of the second stage plate exchanger circulates to the circulating water tank, and enters the geothermal well again for circulating heat exchange.

In some examples, in the summer cooling mode, a low-temperature region of a geothermal reservoir is used as a cooling source of the user cooling circulation, heat of the user is injected from the underground inner pipe, flows through the switchable geothermal well insulation seal, heat exchange is performed between the insulation sleeve and the underground outer pipe, and cold water after heat exchange cools the user.

In some examples, in the cross-season heat storage mode, the renewable heat source is injected from the downhole inner pipe, flows through the switchable geothermal well seal, exchanges heat between the insulated casing and the downhole outer pipe, and exchanges heat to a geothermal reservoir low temperature zone.

In some examples, the on-time and period of the cross-season heat storage mode may be determined according to the type of renewable heat source.

In some examples, the zone depth of the coverage area for the cross-season heat storage is determined from the maximum heating temperature of the renewable heat source.

In some examples, the renewable heat source includes at least one of solar energy, wind energy, and biomass energy.

The sustainable cross-season geothermal energy development system has the following beneficial effects:

(1) the heat supply and cold supply functions are realized through the single well, the great limit development of the capacity of the single well is realized, the initial investment and the operation cost are reduced, and the economic performance is excellent.

(2) By adopting the underground heat exchange technology, water is not taken for heat taking, renewable heat sources are comprehensively utilized, and the remarkable environmental protection benefits of renewable energy sources including geothermal energy are fully exerted.

(3) Renewable heat sources are introduced for seasonal heat storage, and a low-temperature area and a high-temperature area are divided according to the quality of renewable energy sources, so that the recovery capability of geothermal gradient is improved, the long-term sustainable utilization effect of geothermal energy resources is protected, and the safety and stability of energy supply are ensured.

(4) Renewable heat sources are supplemented in the cascade utilization system, and the overall energy utilization efficiency is improved through multi-energy complementation, so that the economic benefit of project development and operation is improved.

(5) The diversity of renewable heat source types and the freedom of entry points greatly improve the applicable range of geothermal energy development, so that the geothermal energy development is not limited by single geothermal resources any more, and the popularization and the application of geothermal energy are facilitated.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic block diagram of a sustainable cross-season geothermal energy development system according to one embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

A sustainable utilized cross-season geothermal energy development system according to an embodiment of the present invention is described below with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram of a sustainable cross-season geothermal energy development system according to one embodiment of the present invention. As shown in fig. 1, the sustainable cross-season geothermal energy development system includes: the system comprises a geothermal well 1, a downhole outer pipe 2, a switchable geothermal well insulation seal 3, a heat insulation sleeve 4, a downhole inner pipe 5, a multistage plate heat exchanger, a heat pump 8, a user 9, a circulating water tank 10, a renewable heat source 11, a cascade utilization system circulating pump 12, a cross-season non-heat system circulating pump 13, a summer cooling system circulating pump 14 and a plurality of valves. The multi-stage plate heat exchange and heat pump 8, the user 9, the circulating water tank 10, the renewable heat source 11, the cascade utilization system circulating pump 12, the cross-season non-heat system circulating pump 13 and the summer cooling system circulating pump 14 are selectively connected through a plurality of valves, wherein the switchable geothermal well insulation 3 is arranged between a low temperature area and a high temperature area of a geothermal reservoir, and the switchable geothermal well insulation 3 is switched to enable the sustainable utilization cross-season geothermal energy development system to enter different energy development modes.

In the example shown in fig. 1, the multistage plate heat exchange and heat pump 8, the cascade utilization system circulation pump 12, the cross-season adiabatic system circulation pump 13, the summer cooling system circulation pump 14, and the like constitute an energy cascade utilization system, and the downhole outer pipe 2 and the downhole inner pipe and the heat insulating sleeve 4 constitute a downhole heat exchange system. The plurality of valves includes at least valves 15 through 22.

In one embodiment of the invention, the different energy development modes comprise at least: a winter multi-energy complementary heat supply mode, a summer cold supply mode and a cross-season heat storage mode.

As mentioned before, the different energy development modes are switched mainly by providing a switchable geothermal well seal 3 between the low temperature zone and the high temperature zone of the geothermal reservoir. In winter, the switchable geothermal well insulation seal 3 is opened, a passage from a well head to the well bottom is formed between the underground outer pipe 2 and the heat insulation sleeve 4, and circulating water can circulate in the whole well; in summer, the switchable geothermal well seal 3 is closed, the geothermal well 1 is divided into an upper layer and a lower layer, and circulating water can only circulate in the region between the switchable geothermal well seal 3 and a well mouth.

In one embodiment of the invention, geothermal reservoir heat is extracted by downhole heat exchange technology in winter multi-energy complementary heating mode, combined with renewable heat sources 11, and used to heat users 9 via a cascade utilization system, for example, according to the solid arrow cycle in fig. 1. Specifically, circulating water is injected into a heat exchange space formed between the underground outer pipe 2 and the heat insulation sleeve 4 by utilizing the potential energy of the circulating water tank 10, the heat of a geothermal reservoir is extracted through sufficient heat exchange, hot water after heat exchange is sent to a multistage plate along the underground inner pipe 5 for exchanging, and the heat is supplied to a user 9 through the multistage plate exchange and the heat exchange of the heat pump 8.

As shown in fig. 1, the multistage plate heat exchanger includes, for example, but not limited to, at least a first stage plate heat exchanger 6 and a second stage plate heat exchanger 7, tail water after primary side heat exchange of the first stage plate heat exchanger 6 is heated by a renewable heat source 11, the supply water temperature is increased, and then the tail water enters a cascade utilization cycle of the second stage plate heat exchanger 7 and a heat pump 8, so that the geothermal energy and the energy of the renewable heat source 11 can be used in a superimposed manner to increase the heat supply, the tail water after sufficient heat exchange by the second stage plate heat exchanger 7 circulates to a circulation water tank 10, and then enters a geothermal well again for circulating heat exchange. It should be noted that the multi-level board swap in the example shown in fig. 1 only includes the first-level board swap 6 and the second-level board swap 7, however, the number of board swaps may be increased according to the resource situation.

In one embodiment of the invention, in a summer cooling mode, a low-temperature region of a geothermal reservoir is used as a cooling source of a user cooling circulation, heat of a user 9 is injected from an underground inner pipe 5, flows through a switchable geothermal well insulation seal 3, heat exchange is carried out between an insulation sleeve 4 and an underground outer pipe 2, and cold water after heat exchange is used for cooling the user 9.

In one embodiment of the invention, trans-seasonal heat storage may be carried out using renewable heat sources in addition to winter heating. In the seasonal heat storage mode, a renewable heat source 11 is injected from the underground inner pipe 5, flows through the switchable geothermal well insulation seal 3, exchanges heat between the insulation sleeve 4 and the underground outer pipe 2, and exchanges heat to the low-temperature region of the geothermal reservoir, so that the decrease of the geothermal temperature generated by heat supply in winter is compensated, the temperature of the geothermal reservoir is recovered, and the effect of sustainable utilization of geothermal energy is achieved.

Wherein the on-time and period of the cross-season heat storage mode may be determined according to the type of renewable heat source 11. For example, solar heat storage can be started in a period with good illumination effect.

In one embodiment of the present invention, renewable heat source 11 comprises at least one of solar energy, wind energy, and biomass energy.

In one embodiment of the invention, the zone depth of the seasonal heat storage covered area is determined from the maximum heating temperature of the renewable heat source. Specifically, the low temperature zone of the geothermal reservoir, which is also referred to herein as the primary region of trans-seasonal heat storage, will be determined by the maximum heating temperature of the renewable heat source 11, with a subsurface depth selected to match that temperature.

To sum up, the sustainable-utilization cross-season geothermal energy development system mainly comprises a geothermal well, a renewable heat source, an energy gradient utilization system (plate exchange and heat pump system), a switchable geothermal well insulation seal, an underground heat exchange system (underground outer pipe of the geothermal well, underground inner pipe of the geothermal well and heat insulation sleeve) and the like, wherein the renewable heat source is combined with geothermal energy, the technical effect of the traditional geothermal energy supply is improved by cross-season heat storage, multi-energy complementation and energy gradient utilization, and the economic benefit of single-well development is enlarged; the whole design of the system adopts a switchable and selectable design, and the entry point of a renewable heat source can be determined at will according to the requirements of users, so that the use flexibility is improved; the type of the starting and regenerating heat source can be freely selected according to the local resources of the project, so that the application range of future development is widened; the system level of geothermal energy cascade utilization can be adjusted according to actual requirements. Namely, the sustainable-utilization cross-season geothermal energy development system is wide in application range, good in long-term operation economy and remarkable in environmental protection benefit, the problems of small energy supply of a geothermal single well, long-term heat consumption attenuation and the like are thoroughly solved, the heat source stability and economic optimality of geothermal energy utilization are improved, the sustainability of geothermal resources is protected while geothermal energy is developed, and the sustainable-utilization cross-season geothermal energy development system is suitable for large-scale development, popularization and application.

The sustainable cross-season geothermal energy development system has the following beneficial effects:

(1) the heat supply and cold supply functions are realized through the single well, the great limit development of the capacity of the single well is realized, the initial investment and the operation cost are reduced, and the economic performance is excellent.

(2) By adopting the underground heat exchange technology, water is not taken for heat taking, renewable heat sources are comprehensively utilized, and the remarkable environmental protection benefits of renewable energy sources including geothermal energy are fully exerted.

(3) Renewable heat sources are introduced for seasonal heat storage, and a low-temperature area and a high-temperature area are divided according to the quality of renewable energy sources, so that the recovery capability of geothermal gradient is improved, the long-term sustainable utilization effect of geothermal energy resources is protected, and the safety and stability of energy supply are ensured.

(4) Renewable heat sources are supplemented in the cascade utilization system, and the overall energy utilization efficiency is improved through multi-energy complementation, so that the economic benefit of project development and operation is improved.

(5) The diversity of renewable heat source types and the freedom of entry points greatly improve the applicable range of geothermal energy development, so that the geothermal energy development is not limited by single geothermal resources any more, and the popularization and the application of geothermal energy are facilitated.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.