A wind-solar-electric energy storage system based on geothermal utilization principle

Abstract

The application provides a wind-solar-electricity energy storage system based on the geothermal utilization principle, and relates to the field of geothermal power generation. The system comprises a power supply device, a heating device, a heat exchange device and a power generation device. The power supply device is used for storing the electricity generated by a wind energy generator set and a solar panel, and transmitting the electricity to a heating coil in a wellbore through an output cable. The heating device is used for heating the aquifer and the granite layer by the heat energy generated by the heating coil, and storing the heat energy. The heat exchange device is used for converting the heat energy of the aquifer and the granite layer into the internal energy of water, so as to obtain water or water vapor. The power generation device is used for converting the water or water vapor into high-temperature and high-pressure steam, and driving a steam turbine generator set to run for power generation. The electricity generated by the wind energy and the solar energy is used for heating the aquifer and the granite layer in the stratum, so that the heat source in the stratum is greatly improved, the production temperature of the heat exchange medium is improved, the required temperature of geothermal power generation is reached, and the geothermal power generation is realized.

Description

Technical Field

[0001] This application relates to the field of geothermal power generation, and more particularly to a wind and solar energy storage system based on the principle of geothermal utilization. Background Technology

[0002] With the advancement of science and technology and the rapid development of the social economy, resource utilization is gradually increasing. As the need for carbon peaking and carbon neutrality becomes increasingly urgent, the utilization of clean energy has received significant attention. Solar and wind energy are inexhaustible renewable energy sources; however, these two energy sources are affected by sunlight and wind intensity, resulting in uneven and fluctuating electricity generation. This leads to situations where unstable electricity cannot be used for residential power generation, and when there is excess electricity, it cannot be fully absorbed and converted, resulting in waste. Therefore, how to effectively store solar and wind energy has become an urgent issue.

[0003] Currently, medium-deep geothermal resources are divided into hydrothermal geothermal energy and dry hot rock geothermal energy.

[0004] Hydrothermal geothermal energy is extracted by directly drawing groundwater for use in building heating and cooling, hot springs, etc., and then reinjected back into the aquifer for reuse. Dry hot rock geothermal energy, on the other hand, uses carbon dioxide blasting and hydraulic fracturing to create a network of fractures in the granite, connecting the injection well and the production well through the fracture network, and then introducing a heat exchange medium to extract the energy from the granite in the formation.

[0005] Due to the influence of geological conditions and stratum depth of the geothermal reservoir, the stratum temperature is not high, resulting in a low temperature of the heat exchange medium at the outlet. Therefore, most of the geothermal energy cannot be used for power generation and can only be used for heating and cooling of buildings. Summary of the Invention

[0006] The purpose of this invention is to fill the technological gap in power generation using hydrothermal geothermal energy and to provide a wind, solar and energy storage system based on the principle of geothermal utilization.

[0007] The above-mentioned objective of this application is achieved through the following technical solution:

[0008] The system includes: power supply unit, heating unit, heat exchange unit, and power generation unit;

[0009] The power supply equipment includes: output cables, wind turbine generators, and solar panels;

[0010] The power supply device is used to utilize the electrical energy stored in the wind turbine generator and solar panels, and transmit it to the heating coil inside the wellbore through the output cable;

[0011] The heating device is used to heat the aquifer and granite layer through the heat energy generated by the heating coil, and to store the heat energy;

[0012] The heat exchange device is used to convert the thermal energy of the aquifer and granite layer into the internal energy of the water to obtain water or water vapor;

[0013] The power generation unit is used to convert water or steam into high-temperature and high-pressure steam, which drives the steam turbine generator set in the power generation unit to generate electricity.

[0014] The heating device includes: a heating coil, a heat-conducting fluid, a packer, and a booster pump.

[0015] The heating coil is placed in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid.

[0016] The heat transfer fluid is a mixture of water, graphene, and carbon nanotubes, or a mixture of water, silicon carbide, and aluminum nitride.

[0017] The heat exchange device includes: a coaxial sleeve, an open filter pipe, a sand baffle, a packer, a water pump, and a booster pump.

[0018] Sand filters include: sand separators, coarse filters, and fine filters.

[0019] The coaxial sleeve is installed to the depth of the granite layer. In the granite layer section, the coaxial sleeve is solidified using a thermally conductive material.

[0020] The filter pipe is installed to the depth of the aquifer.

[0021] The thermally conductive material is thermally conductive cement.

[0022] The power generation unit includes: an evaporator, a steam turbine generator set, a cooler, and a generator.

[0023] A wind and solar energy storage method based on the principle of geothermal utilization, the method comprising:

[0024] Harvesting stored electrical energy from wind turbine generators and solar panels;

[0025] The aquifer and granite layer are heated by heating coils and storing electrical energy, and the thermal energy is stored.

[0026] By converting stored thermal energy, geothermal energy from aquifers and granite layers into the internal energy of water, water or water vapor can be obtained.

[0027] Water or steam is converted into high-temperature, high-pressure steam to drive the steam turbine generator set in the power generation unit to generate electricity, realizing combined solar and wind power generation of medium-deep geothermal energy.

[0028] The beneficial effects of the technical solution provided in this application are:

[0029] This invention designs a combined solar and wind power generation system for medium-deep geothermal energy. This technology converts the unstable and fluctuating electrical energy generated by solar and wind energy into thermal energy. By increasing the temperature of the aquifer and granite, the temperature of the thermal storage medium is increased, achieving the effect of geothermal power generation. This solves the problem of excess and unstable energy from solar and wind energy, which leads to low energy utilization efficiency. At the same time, it also solves the problem that the temperature of some medium-deep geothermal energy is too low to be used for geothermal power generation, thereby protecting geothermal energy resources, preventing thermal storage temperature decay, and ensuring the sustainable utilization of geothermal storage. Attached Figure Description

[0030] The present application will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0031] Figure 1 This is a first schematic diagram of the solar-wind combined power generation system in the embodiments of this application;

[0032] Figure 2 This is a second schematic diagram of the solar-wind combined power generation system in the embodiments of this application. Detailed Implementation

[0033] To provide a clearer understanding of the technical features, objectives, and effects of this application, the specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0034] The embodiments of this application provide a wind and solar energy storage system based on the principle of geothermal utilization.

[0035] Please refer to Figure 1 , Figure 1 This is a first schematic diagram of a combined solar and wind power generation system based on geothermal energy utilization principle and wind-solar energy storage system according to an embodiment of this application, including:

[0036] The system includes: power supply unit, heating unit, heat exchange unit, and power generation unit;

[0037] The power supply equipment includes: output cables, wind turbine generators, and solar panels;

[0038] The power supply device is used to utilize the electrical energy stored in the wind turbine generator and solar panels, and transmit it to the heating coil inside the wellbore through the output cable;

[0039] This application provides an embodiment as follows: the power supply device utilizes the electrical energy stored in a wind turbine generator and solar panels, and transmits it to the heating coil inside the wellbore via an output cable. The main purpose is to convert uneven and unstable electrical energy into effective heat energy, thereby improving energy utilization efficiency. The wind turbine generator transmits the energy to the substation via a box-type transformer, and then the low voltage is transmitted to the heating coil; after the solar panels absorb energy, the direct current is converted into alternating current by a grid-connected inverter, then transmitted to the power transformer, and finally to the heating coil.

[0040] The heating device is used to heat the aquifer and granite layer through the heat energy generated by the heating coil, and to store the heat energy;

[0041] The heat exchange device is used to convert the thermal energy of the aquifer and granite layer into the internal energy of the water to obtain water or water vapor;

[0042] The power generation unit is used to convert water or steam into high-temperature and high-pressure steam, which drives the steam turbine generator set in the power generation unit to generate electricity.

[0043] The heating device includes: a heating coil, a heat-conducting fluid, a packer, and a booster pump.

[0044] The heating coil is placed in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid.

[0045] The heat transfer fluid is a mixture of water, graphene, and carbon nanotubes, or a mixture of water, silicon carbide, and aluminum nitride.

[0046] This application provides an embodiment as follows: a heating coil is inserted into a hole using a drill rod. In an aquifer, the sandstone is loose and porous, allowing it to directly and completely contact the heating coil and conduct heat directly. In a granite layer, the granite is dense, hard, and structurally complete, preventing it from fully contacting the heating coil. Therefore, heat needs to be indirectly conducted through a heat-conducting fluid.

[0047] The heat exchange device includes: a coaxial sleeve, an open filter pipe, a sand baffle, a packer, a water pump, and a booster pump.

[0048] Sand filters include: sand separators, coarse filters, and fine filters.

[0049] As one embodiment, a sand baffle is installed in the aquifer section to prevent sand and gravel blockage. The heat exchange device employs both open and closed heat exchange systems for simultaneous heat exchange. The closed heat exchange system uses a coaxial sleeve heat exchanger, through which a heat exchange medium is introduced to collect heat from the granite layer. An open filter pipe is inserted around the coaxial sleeve to extract hot water from the aquifer. A booster pump is used to introduce water into the inner tube of the coaxial sleeve, where heat is indirectly transferred between the water and the granite layer at the bottom of the coaxial sleeve. Water is then extracted from the outer tube of the coaxial sleeve. Within the aquifer, a water pump is used to extract water from the aquifer, which is then extracted from the outer filter pipe.

[0050] The coaxial sleeve is installed to the depth of the granite layer. In the granite layer section, the coaxial sleeve is solidified using a thermally conductive material.

[0051] The filter pipe is installed to the depth of the aquifer.

[0052] The thermally conductive material is thermally conductive cement.

[0053] The power generation unit includes: an evaporator, a steam turbine generator set, a cooler, and a generator.

[0054] In one embodiment, the power generation unit utilizes water or steam extracted from a heat exchanger, which is then passed through an evaporator to obtain high-temperature, high-pressure steam. This steam drives a steam turbine generator set. The water, after its heat is transferred to the high-temperature, high-pressure steam, passes through a cooler and returns to a storage tank. The power generation unit generates electricity in four ways: dry steam power generation, flash evaporation power generation, dual-medium power generation, and full-flow power generation. The appropriate power generation technology must be selected based on the temperature, composition, and other properties of the heat exchange medium.

[0055] A wind and solar energy storage method based on the principle of geothermal utilization, the method comprising:

[0056] Water is injected into the aquifer and into the inner tube of the coaxial casing, and then extracted from the outer tube.

[0057] Harvesting stored electrical energy from wind turbine generators and solar panels;

[0058] The aquifer and granite layer are heated by heating coils and storing electrical energy, and the thermal energy is stored.

[0059] By converting stored thermal energy, geothermal energy from aquifers and granite layers into the internal energy of water, water or water vapor can be obtained.

[0060] Water or steam is converted into high-temperature, high-pressure steam to drive the steam turbine generator set in the power generation unit to generate electricity, realizing combined solar and wind power generation of medium-deep geothermal energy.

[0061] This application provides an embodiment as follows: a large amount of water is injected into the aquifer through an injection well, and then a heating coil is placed inside to simultaneously heat both the granite and the aquifer. The aquifer can be directly heated in contact, but due to the dense, hard, and structurally intact granite layer, direct contact heating is not possible. Therefore, a heat-conducting fluid is needed to transfer heat to the granite. Granite has a high thermal conductivity, resulting in better heat transfer. Some of the heat from the granite is transferred to the aquifer through interlayer heat transfer, thus creating two methods to heat the aquifer. This method continuously stores energy in the formation, thereby increasing the formation temperature and the temperature of the extracted heat exchange medium. Then, in the production well, an open-closed heat exchange system is used simultaneously. Water is introduced through a coaxial sleeve from the inner pipe, and after heat exchange, water is extracted from the outer pipe. Simultaneously, water from the aquifer is drawn through an open filter pipe and then fed into an evaporator for power generation by a turbine generator set. Finally, the cooling water is returned to the storage tank.

[0062] This application provides an embodiment as follows: the heat-conducting fluid includes, but is not limited to, a mixed fluid of water + graphene + carbon nanotubes, or a mixed fluid of water + silicon carbide + aluminum nitride. A multi-hole system can be used to store heat in the formation through a heating device, employing a surrounding perforation pattern with a production well in the center and injection wells (heat storage wells) around the perimeter.

[0063] This application provides an embodiment as follows, and the specific implementation process includes:

[0064] Step 1: First, based on the geological and topographical conditions, a suitable drilling location needs to be selected. Two wells (injection well and production well) need to be drilled. At the same time, the area is required to have the ability to generate solar or wind power, but high solar radiation intensity and strong wind intensity are not required, because it is only to store the energy of solar and wind energy in the strata and accumulate the energy of geothermal energy, which will not have a negative impact on the geothermal power generation system.

[0065] Step 2: Drill holes in both wells, reaching the granite layer. The drilling depth into the granite layer is determined by the drilling difficulty and economic efficiency, requiring preliminary calculations. As shown in the diagram, if the wells contain sandstone and aquifer layers, then the conditions for later development are met. Casing is installed in the surface soil and sandstone sections of both wells, and the casing is secured with cement.

[0066] Step 3: Next, in-hole operations are performed simultaneously on both wells. In the injection well, hydraulic fracturing is used to fracture the granite. After generating numerous cracks, a heat-conducting fluid prepared on the surface is delivered to the granite section through the drill pipe, allowing the fluid to fully contact the granite layer and conduct heat. A packer is then installed between the aquifer and the granite layer to separate the two rock sections and prevent interference. The packer is not completely sealed in the middle to facilitate the placement of the heating coil into the granite section. In the production well, a coaxial casing is first lowered into the granite section, then fixed with thermally conductive cement. A packer is used to seal the gap between the aquifer and the granite layer. A sand trap is then fixed in the aquifer section, and a large-diameter filter pipe with the same diameter as the sand trap is installed around the coaxial casing, with its orifice size larger than that of the coaxial casing.

[0067] Step 4: Then, energy storage operations are performed on the formation. In the injection well, a booster pump injects water into the aquifer via pipeline. The pipeline is then lifted out of the aquifer, and a heating coil is used below the drill pipe to heat the granite section. The heating coil's heating range covers both the aquifer and granite sections. The electricity generated by solar and solar power is then transmitted to the heating coil via an output cable to generate heat for the formation. Temperature sensors are installed in the production well within the aquifer and granite layers to continuously monitor temperature changes. Once the formation temperature reaches the required level for power generation, water is extracted from the aquifer through a filter pipe and pumped into the inner pipe of the coaxial casing via a booster pump, allowing it to exchange heat with the granite layer. Water is then extracted from the outer pipe, thus raising the water temperature to the power generation temperature.

[0068] Step 5: Finally, geothermal power generation is carried out. The extracted water is fed into the evaporator to generate high-pressure, high-temperature steam, which is used to power a steam turbine generator set. This converts the generated heat energy into mechanical energy. The resulting low-temperature water is then cooled to room temperature by a condenser and transported back to the storage tank. The low-temperature heat generated in this process can also be used by a small generator via cables to heat the heating coils.

[0069] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure.

[0070] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A wind-solar-energy storage system based on the principle of geothermal utilization, characterized in that, The system includes: power supply unit, heating unit, heat exchange unit, and power generation unit; The heating device includes: a heating coil, a heat-conducting fluid, a packer, and a first booster pump; the first booster pump is installed in a pipeline for inputting water into the injection well; The heating coil is placed in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid. The thermally conductive fluid is a mixture of water-graphene-carbon nanotubes or a mixture of water-silicon carbide-aluminum nitride. The heat exchange device includes: a coaxial sleeve, an open filter pipe, a sand baffle, a packer, a water pump, and a second booster pump; the second booster pump is configured to introduce water into the inner tube of the coaxial sleeve. Sand filters include: sand removers, coarse filters, and fine filters; sand filters are installed in the aquifer section of the production well; The coaxial sleeve is installed to the depth of the granite layer. In the granite layer section, the coaxial sleeve is solidified using a thermally conductive material. The installation depth of the open filter pipe extends into the aquifer; The thermally conductive material is thermally conductive cement; The power supply equipment includes: output cables, wind turbine generators, and solar panels; The power supply device is used to utilize the electrical energy stored in the wind turbine generator and solar panels, and transmit it to the heating coil inside the wellbore through the output cable; The heating device is used to heat the aquifer and granite layer through the heat energy generated by the heating coil, and to store the heat energy; The heat exchange device is used to convert the thermal energy of the aquifer and granite layer into the internal energy of the water to obtain water or water vapor; The power generation unit is used to convert water or steam into high-temperature and high-pressure steam, which drives the steam turbine generator set in the power generation unit to generate electricity; The power generation unit includes: an evaporator, a steam turbine generator set, a cooler, and a generator.

2. A wind-solar-energy storage method based on the principle of geothermal utilization, implemented based on the wind-solar-energy storage system based on the principle of geothermal utilization as described in claim 1, characterized in that, The method includes: Harvesting stored electrical energy from wind turbine generators and solar panels; The aquifer and granite layer are heated by heating coils and storing electrical energy, and the thermal energy is stored. By converting stored thermal energy, geothermal energy from aquifers and granite layers into the internal energy of water, water or water vapor can be obtained. Water or steam is converted into high-temperature, high-pressure steam to drive the steam turbine generator set in the power generation unit to generate electricity, realizing combined solar and wind power generation of medium-deep geothermal energy.

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