Wind-light-electricity energy storage system based on terrestrial heat utilization principle

Abstract

The invention provides a wind-light-electricity energy storage system based on a terrestrial heat utilization principle, and relates to the field of terrestrial heat 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 transmitting electric energy stored by the wind power generator set and the solar panel to the heating coil in the shaft through the output end cable; the heating device is used for heating the aquifer and the granite layer through heat energy generated by the heating coil and storing the heat energy; the heat exchange device is used for converting heat energy of the aquifer and the granite layer into internal energy of water to obtain water or water vapor; the power generation device is used for converting water or water vapor into high-temperature and high-pressure steam and driving the steam turbine generator unit to operate for power generation. Electric energy generated by wind energy and solar energy is combined to heat an aquifer and a granite layer in a stratum, so that a heat source in the stratum is greatly increased, the extraction temperature of a heat exchange medium is increased, the temperature required by geothermal power generation is achieved, and geothermal power generation is achieved.

Description

Technical Field

[0001] The present application relates to the field of geothermal power generation, and in particular to a wind and photovoltaic energy storage system based on the principle of geothermal utilization. Background Art

[0002] With the advancement of science and technology, social economy is developing in full swing, so the utilization rate of resources is also gradually increasing. With the increasing urgency of carbon peak and carbon neutrality, the use of clean energy has received people's attention. Solar energy and wind energy are inexhaustible renewable energy sources, but these two energy sources are affected by sunlight and wind intensity, making the generated electricity uneven and volatile. As a result, when the electricity is unstable, it cannot be used for civilian power generation. When the electricity is in excess, it cannot be absorbed and converted, resulting in waste. Therefore, how to effectively store solar energy and wind energy has become an urgent issue.

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

[0004] The exploitation method of hydrothermal geothermal energy is to directly extract groundwater for use in building heating and cooling, hot springs, etc., and then reinject it into the aquifer for repeated use; while hot dry rock geothermal energy uses carbon dioxide blasting fracturing, hydraulic fracturing and other methods to create a fracture network in the granite, connect the injection well and the production well through the fracture network, and then introduce heat exchange medium to extract the energy of the granite in the formation.

[0005] Due to the influence of the geological conditions and depth of the heat storage, the temperature of the stratum is not high, resulting in the 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 the present invention is to provide a wind and photovoltaic energy storage system based on the principle of geothermal utilization in order to fill the technical gap in using hydrothermal geothermal energy to generate electricity.

[0007] The above-mentioned purpose of the present application is achieved through the following technical solutions: The system includes: a power supply device, a heating device, a heat exchange device and a power generation device; The power supply device includes: output end cables, wind power generator sets and solar panels; The power supply device is used to utilize the electric energy stored in the wind power generator set and the solar panel to transmit it to the heating coil in the wellbore through the output end cable; The heating device is used to heat the aquifer and the granite layer by means of the heat energy generated by the heating coil, and store the heat energy; The heat exchange device is used to convert the thermal energy of the aquifer and the granite layer into the internal energy of water to obtain water or water vapor; The power generation device is used to convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to operate and generate electricity.

[0008] The heating device comprises: a heating coil, a heat transfer fluid, a packer and a booster pump.

[0009] The heating coil is arranged in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid; The heat transfer fluid is a mixed fluid of water-graphene-carbon nanotubes or a mixed fluid of water-silicon carbide-aluminum nitride.

[0010] The heat exchange device comprises: a coaxial casing, an open water filter pipe, a sand blocker, a packer, a water pump and a booster pump; Sand inhibitors include: desanders, coarse filters and fine filters.

[0011] The coaxial sleeve is installed to a depth deep into the granite layer, and in the granite layer section, the coaxial sleeve is consolidated with a heat-conducting material; The installation depth of the filter pipe is into the aquifer.

[0012] The heat conducting material is heat conducting cement.

[0013] The power generation device comprises: an evaporator, a steam turbine generator set, a cooler and a generator.

[0014] A wind and photovoltaic energy storage method based on the principle of geothermal utilization, the method comprising: Access to stored electricity from wind turbines and solar panels; Heating aquifers and granite layers and storing thermal energy through heating coils and storing electrical energy; By converting the stored thermal energy, the geothermal energy of the aquifer and the geothermal energy of the granite layer into the internal energy of water, water or water vapor is obtained; Convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to generate electricity, thereby realizing solar-wind combined power generation in medium- and deep-layer geothermal energy.

[0015] The beneficial effects of the technical solution provided by this application are: The present invention designs a solar-wind combined power generation system for mid- to deep-layer geothermal energy. This technology converts unstable and fluctuating electrical energy generated by solar energy and wind energy into thermal energy. By increasing the temperature of the aquifer and the temperature of the granite, the temperature of the heat storage medium is increased, thereby achieving the effect of geothermal power generation. This solves the problem of excess and unstable solar and wind energy, which leads to low energy utilization efficiency. At the same time, it solves the problem that the temperature of geothermal energy in some mid- to deep-layer strata is relatively low and is insufficient for geothermal power generation, thereby protecting geothermal energy resources, preventing the temperature decay of the heat storage, and ensuring the sustainable utilization of geothermal storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present application will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 is a first schematic diagram of a solar-wind combined power generation system in an embodiment of the present application; Figure 2 This is the second schematic diagram of the solar-wind combined power generation system in the embodiment of the present application. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation methods of the present application are now described in detail with reference to the accompanying drawings.

[0018] The embodiments of the present application provide a wind and solar energy storage system based on the principle of geothermal utilization.

[0019] Please refer to Figure 1 , Figure 1 This is a first schematic diagram of a solar-wind combined power generation system of a wind-photovoltaic energy storage system based on the geothermal utilization principle in an embodiment of the present application, including: The system includes: a power supply device, a heating device, a heat exchange device and a power generation device; The power supply device includes: output end cables, wind power generator sets and solar panels; The power supply device is used to utilize the electric energy stored in the wind power generator set and the solar panel to transmit it to the heating coil in the wellbore through the output end cable; The present application provides an embodiment as follows: the power supply device uses the electric energy stored in the wind power generator set and the solar panel to transfer it to the heating coil in the wellbore through the output end cable. The main purpose is to convert uneven and unstable electric energy into effective heat energy to improve energy utilization efficiency. The wind power generator set transmits the energy to the substation through a box transformer, and then transmits the low voltage to the heating coil; after the solar panel absorbs the energy, the direct current is converted into alternating current through the grid-connected inverter, and then transmitted to the power transformer, and finally to the heating coil.

[0020] The heating device is used to heat the aquifer and the granite layer by means of the heat energy generated by the heating coil, and store the heat energy; The heat exchange device is used to convert the thermal energy of the aquifer and the granite layer into the internal energy of water to obtain water or water vapor; The power generation device is used to convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to operate and generate electricity.

[0021] The heating device comprises: a heating coil, a heat transfer fluid, a packer and a booster pump.

[0022] The heating coil is arranged in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid; The heat transfer fluid is a mixed fluid of water-graphene-carbon nanotubes or a mixed fluid of water-silicon carbide-aluminum nitride.

[0023] The present application provides an embodiment as follows: a heating coil is sent into a hole by a drill rod. In the aquifer, the sandstone is loose and porous and can be in direct and complete contact with the heating coil, thereby directly conducting heat. In the granite layer, the granite layer is dense and hard and has a complete structure and cannot be in complete contact with the heating coil, so it is necessary to indirectly conduct heat through a heat-conducting fluid.

[0024] The heat exchange device comprises: a coaxial casing, an open water filter pipe, a sand blocker, a packer, a water pump and a booster pump; Sand inhibitors include: desanders, coarse filters and fine filters.

[0025] As an embodiment, a sand blocker is installed in the aquifer section to prevent blockage by sand and gravel. The heat exchange device uses an open and closed heat exchange system for simultaneous heat exchange. The closed heat exchange system uses a coaxial sleeve heat exchange device, and a heat exchange medium is introduced into the granite layer for heat extraction. An open water filter pipe is inserted around the coaxial sleeve to extract hot water from the aquifer. A booster pump is used to pass water into the inner tube of the coaxial sleeve. The water indirectly transfers heat with the granite layer at the bottom of the coaxial sleeve, and water is pumped out from the outer tube of the coaxial sleeve; in the aquifer, a pumping pump is used to extract water from the aquifer and pump water out from the outer water filter pipe.

[0026] The coaxial sleeve is installed to a depth deep into the granite layer, and in the granite layer section, the coaxial sleeve is consolidated with a heat-conducting material; The installation depth of the filter pipe is into the aquifer.

[0027] The heat conducting material is heat conducting cement.

[0028] The power generation device comprises: an evaporator, a steam turbine generator set, a cooler and a generator.

[0029] As an example, the power generation device uses water or water vapor extracted from the heat exchange device, and then obtains high-temperature and high-pressure steam after passing through the evaporator to drive the steam turbine generator set to operate. The water after the heat is transferred to the high-temperature and high-pressure steam passes through the cooler and returns to the water storage tank. There are four ways for the power generation device to generate electricity, namely dry steam power generation technology, flash evaporation power generation technology, dual-fluid power generation technology, and full-flow power generation technology. The appropriate power generation technology needs to be selected according to the temperature, components, ingredients and other properties of the heat exchange medium.

[0030] A wind and photovoltaic energy storage method based on the principle of geothermal utilization, the method comprising: Injecting water into the aquifer, as well as injecting water into the inner tube of the coaxial casing and then extracting it from the outer tube; Access to stored electricity from wind turbines and solar panels; Heating aquifers and granite layers and storing thermal energy through heating coils and storing electrical energy; By converting the stored thermal energy, the geothermal energy of the aquifer and the geothermal energy of the granite layer into the internal energy of water, water or water vapor is obtained; Convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to generate electricity, thereby realizing solar-wind combined power generation in medium- and deep-layer geothermal energy.

[0031] The present 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 to heat the granite and the aquifer at the same time. The aquifer can be heated by direct contact, but because the granite layer is dense and hard, and the structure is complete, it cannot be heated by direct contact, so it is necessary to transfer heat to the granite through a heat transfer fluid. Granite has a high thermal conductivity and better thermal conductivity, so part of the heat in the granite will be transferred to the aquifer through interlayer heat transfer, thereby forming two ways to heat the aquifer, and energy is stored in the formation in this way, thereby increasing the temperature in the formation and the temperature of the heat exchange medium. Then, in the production well, an open and closed heat exchange system is used at the same time, and water is passed from the inner pipe using a coaxial sleeve, and water is extracted from the outer pipe after heat exchange. At the same time, water in the aquifer is extracted in the open filter pipe, and then it is passed into the evaporator for power generation of the steam turbine generator set, and finally the cooling water is returned to the water storage tank.

[0032] The present application provides an embodiment as follows, the heat transfer fluid includes but is not limited to a mixed fluid of water + graphene + carbon nanotubes, a mixed fluid of water + silicon carbide + aluminum nitride, etc. A group of holes can be used to store heat in the formation through a heating device, and a surrounding hole arrangement is adopted, with a production well in the middle and injection wells (heat storage wells) on all sides.

[0033] The present application provides an embodiment as follows, and the specific implementation process includes: Step 1: First, you need to select a suitable drilling location based on geological and topographic conditions. You need to drill two wells (an injection well and a production well). At the same time, the area is required to have the ability to generate solar or wind power, but it does not require high sunshine intensity or strong wind intensity, because it only stores the energy of solar and wind energy in the strata, allowing geothermal energy to accumulate, which will not have a negative impact on the geothermal power generation system.

[0034] Step 2: Drill two wells and drill into the granite layer respectively. The depth of drilling into the granite is determined by the difficulty of drilling and the economic benefit ratio, which requires preliminary calculation. As shown in the figure, when the middle contains sandstone layers and aquifers, it meets the sufficient conditions for later development. Casings are lowered in the surface soil section and sandstone section of the two wells respectively, and the casings are fixed with cement.

[0035] Step 3: Next, we will perform in-hole operations on both wells at the same time. In the injection well, we use hydraulic fracturing to fracture the granite. After a large number of cracks are generated, the heat transfer fluid prepared on the ground is transported to the granite section through the drill pipe, so that the heat transfer fluid is fully in contact with the granite layer to conduct heat. Then, a packer is installed between the aquifer and the granite layer to separate the two rock sections without interference. The middle of the divider is not sealed, which facilitates the lowering of the heating coil into the granite section. In the production well, we first lower the coaxial casing to the granite section, and then fix it with thermal conductive cement in the granite section, use a packer to seal between the aquifer and the granite layer, and then fix the sand blocker in the aquifer section. Then install a large-diameter water filter pipe on the periphery of the coaxial casing, with the same diameter as the sand blocker, and its aperture size must be larger than the diameter of the coaxial casing.

[0036] Step 4: Then perform energy storage operations on the formation. In the injection well, use a booster pump to inject water into the aquifer through a pipeline, then lift the pipeline out of the aquifer, and then use the heating coil under the drill pipe to the granite section. The heating range of the heating coil is within the aquifer and granite layer. Then the electricity generated by solar energy and light energy is transmitted to the heating coil through the output end cable to generate heat to heat the formation. By setting temperature sensors in the production well, in the aquifer and granite layer, the temperature changes in the formation are monitored at all times, and the temperature in the formation reaches the temperature required for power generation. The water in the aquifer is extracted from the filter pipe, and the water is injected from the inner tube of the coaxial casing through a booster pump to allow it to exchange heat with the granite layer, and then water is extracted from the outer pipe to heat the water to the power generation temperature.

[0037] Step 5: Finally, geothermal power generation is carried out. The produced water is passed into the evaporator to generate high-pressure and high-temperature steam for the steam turbine generator set, thereby converting the generated heat energy into mechanical energy. The low-temperature water obtained is then cooled to room temperature through the condenser and transported back to the water storage tank. The low heat generated in this process can also be used by a small generator through cables to heat the heating coil.

[0038] The above are only exemplary embodiments of the present disclosure and cannot be used to limit the scope of the present disclosure. That is, any equivalent changes and modifications made according to the teachings of the present disclosure are still within the scope of the present disclosure.

[0039] This application is intended to cover any variation, use or adaptation of the present disclosure, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art not described in the present disclosure. The description and examples are to be regarded as exemplary only, and the scope and spirit of the present disclosure are defined by the claims.

Claims

1. A wind and photovoltaic energy storage system based on the principle of geothermal utilization, characterized in that: The system includes: a power supply device, a heating device, a heat exchange device and a power generation device; The power supply device includes: output end cables, wind power generator sets and solar panels; The power supply device is used to utilize the electric energy stored in the wind power generator set and the solar panel to transmit it to the heating coil in the wellbore through the output end cable; The heating device is used to heat the aquifer and the granite layer by means of the heat energy generated by the heating coil, and store the heat energy; The heat exchange device is used to convert the thermal energy of the aquifer and the granite layer into the internal energy of water to obtain water or water vapor; The power generation device is used to convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to operate and generate electricity.

2. A wind and photovoltaic energy storage system based on the geothermal utilization principle as claimed in claim 1, characterized in that: The heating device comprises: a heating coil, a heat transfer fluid, a packer and a booster pump.

3. A wind-photovoltaic energy storage system based on geothermal utilization principle as claimed in claim 2, characterized in that: The heating coil is arranged in the aquifer and the granite layer; the heating coil in the granite layer is wrapped with a heat-conducting fluid; The heat transfer fluid is a mixed fluid of water-graphene-carbon nanotubes or a mixed fluid of water-silicon carbide-aluminum nitride.

4. A wind-photovoltaic energy storage system based on geothermal utilization principle as claimed in claim 1, characterized in that: The heat exchange device comprises: a coaxial casing, an open water filter pipe, a sand blocker, a packer, a water pump and a booster pump; Sand inhibitors include: desanders, coarse filters and fine filters.

5. A wind-photovoltaic energy storage system based on geothermal utilization principle as claimed in claim 4, characterized in that: The coaxial sleeve is installed to a depth deep into the granite layer, and in the granite layer section, the coaxial sleeve is consolidated with a heat-conducting material; The installation depth of the filter pipe is into the aquifer.

6. A wind-photovoltaic energy storage system based on geothermal utilization principle as claimed in claim 5, characterized in that: The heat conducting material is heat conducting cement.

7. A wind-photovoltaic energy storage system based on geothermal utilization principle as claimed in claim 1, characterized in that: The power generation device comprises: an evaporator, a steam turbine generator set, a cooler and a generator.

8. A wind and photovoltaic energy storage method based on the principle of geothermal utilization, which is implemented based on a wind and photovoltaic energy storage system based on the principle of geothermal utilization as claimed in any one of claims 1 to 7, characterized in that: The method comprises: Access to stored electricity from wind turbines and solar panels; Heating aquifers and granite layers and storing thermal energy through heating coils and storing electrical energy; By converting the stored thermal energy, the geothermal energy of the aquifer and the geothermal energy of the granite layer into the internal energy of water, water or water vapor is obtained; Convert water or water vapor into high-temperature and high-pressure steam to drive the steam turbine generator set in the power generation device to generate electricity, thereby realizing solar-wind combined power generation in medium- and deep-layer geothermal energy.

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