Artificial geothermal energy storage and light-wind combined supply power generation system and method

Abstract

The invention provides an artificial geothermal energy storage and light-wind combined supply power generation system and method, and relates to the technical field of energy storage of light-wind power generation. The system comprises a power supply device, a heating device, an underground reservoir, a heat exchange device and a power generation device. The underground reservoir is a closed water containing body formed by a steel framework, a steel wall body and an outer heat insulation material, and a low-salinity water body is injected into the closed water containing body. Wind energy or solar energy supplies energy to the heating device through the power supply device, water is heated and stored, and the heat exchange device extracts hot water to generate organic working medium steam to drive the power generation device to generate power. According to the invention, efficient utilization and peak regulation power generation of renewable energy sources can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage for solar-wind power generation, and in particular to an artificial geothermal energy storage and solar-wind combined power generation system and method. Background Art

[0002] 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 volatile electricity generation, which can lead to unstable power supply. When there is excess electricity, not all of it can be absorbed and converted, resulting in waste, known as "peak power" or "abandoned power." Therefore, finding effective storage for solar and wind energy has become a pressing issue.

[0003] Currently, attempts are being made at home and abroad to use underground aquifers or groundwater in granite as a heat medium to heat the "wasted electricity" generated by wind and solar power generation, and then use the heated groundwater as a heat source to generate electricity to serve the energy storage function of wind and solar power generation.

[0004] However, there are problems: the groundwater has a high degree of mineralization, and mineral precipitation occurs during the heating, water extraction and recharge processes, thus clogging the pipes; the groundwater exists in deep aquifers, which are not closed, and the groundwater is not closed either, resulting in a large amount of heat loss during the heating process; the exploration and development of groundwater requires a lot of money, etc.

[0005] The above-mentioned unfavorable factors limit the implementation of energy storage and wind-solar power generation. Summary of the Invention

[0006] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide an artificial geothermal energy storage and solar-wind combined power generation system and method, filling the technical gap in artificial geothermal power generation.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] An artificial geothermal energy storage and solar-wind combined power generation system, comprising: a power supply device, a heating device, an underground water reservoir, a heat exchange device and a power generation device;

[0009] A power supply device for transmitting electric energy generated by wind power generation and / or solar power generation via an output end cable;

[0010] An underground water reservoir comprises a steel frame, steel walls, external insulation material, and water within the reservoir; the steel frame and the steel walls constitute a closed water container; the external insulation material is applied to the outer surface of the steel walls to reduce heat loss; and the water within the reservoir is clean water with low mineralization.

[0011] a heating device, disposed in the underground water reservoir and electrically connected to the power supply device via the output-end cable, for heating the water in the reservoir to store thermal energy;

[0012] a heat exchange device, connected to the underground water reservoir, for utilizing the hot water in the underground water reservoir to generate organic working fluid steam;

[0013] A power generation device is communicated with the heat exchange device and is used to generate electricity using the organic working fluid steam.

[0014] Preferably, the top of the underground reservoir is 2m from the ground surface.

[0015] Preferably, the power supply device is controlled by a preset intelligent control instruction to supply power to the heating device when wind energy and / or solar energy have peak power or abandoned power, so as to realize energy storage scheduling of renewable energy to reduce peak power and fill valley power.

[0016] Preferably, the underground reservoir is located in an area with stable geological conditions and intact bedrock, and is constructed by excavating a foundation pit with a length of 50m, a width of 40m and a depth of 10m.

[0017] Preferably, when the target installed capacity is 50MW, the effective volume of the underground reservoir is 20,000m 3 .

[0018] Preferably, the underground water reservoir is provided with a temperature and pressure online monitoring interface; the temperature and pressure online monitoring interface is used to collect monitoring data and upload the monitoring data.

[0019] Preferably, the electric heater of the heating device is designed as an independent detachable module; when the independent detachable module is pulled out, automatic power-off protection is triggered, so that the electric heater can be safely replaced without stopping the water supply of the underground reservoir.

[0020] Preferably, the heat exchange device includes a heat exchange cavity, a cold water return pump, an organic working fluid booster pump and an organic working fluid heat increasing pipe arranged in the heat exchange cavity; wherein, the outlet of the cold water return pump is connected to the hot water inlet of the heat exchange cavity, and is used to transport the hot water from the underground water reservoir to the heat exchange cavity; the organic working fluid booster pump drives the organic working fluid to flow through the organic working fluid heat increasing pipe and exchange heat with the hot water to generate high-temperature and high-pressure organic working fluid steam.

[0021] Preferably, the outlet of the cold water return pump is connected to the return cold water inlet of the underground water reservoir, so that the low-temperature water after heat exchange flows back to the underground water reservoir, forming a closed water cycle to maintain the water level in the underground water reservoir.

[0022] A method for generating power by combining artificial geothermal energy storage with solar-wind power generation, comprising:

[0023] The power supply device transmits the electric energy generated by wind power generation and / or solar power generation to the heating device via the output end cable, and the heating device electrically heats the clean water with low mineralization in the underground reservoir to store thermal energy;

[0024] When electrical energy needs to be output, the hot water in the underground reservoir is exchanged with the organic working fluid through the heat exchange device to generate organic working fluid steam;

[0025] transporting the organic working fluid steam to a power generation device to drive the power generation device to generate electricity;

[0026] The water with lowered temperature after heat exchange flows back to the underground reservoir, and the organic working fluid after doing work is cooled and recovered to form a water cycle and a working fluid cycle.

[0027] The present invention discloses the following technical effects:

[0028] The present invention converts the unstable and fluctuating electrical energy generated by solar energy and wind energy into thermal energy, stores the energy by increasing the temperature of the water in artificial geothermal (underground reservoir), and regenerates electricity using the principle of geothermal power generation, thus solving the bottleneck of low clean energy utilization efficiency caused by the excess and instability of solar energy and wind energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 A schematic diagram of the system structure provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of underground reservoir construction provided by an embodiment of the present invention;

[0032] Figure 3 A flowchart of a method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Figure 1 A schematic diagram of the system structure provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the present invention provides an artificial geothermal energy storage and solar-wind combined power generation system, comprising: a power supply device, a heating device, an underground water reservoir, a heat exchange device and a power generation device;

[0036] A power supply device for transmitting electric energy generated by wind power generation and / or solar power generation via an output end cable;

[0037] An underground water reservoir comprises a steel frame, steel walls, external insulation material, and water within the reservoir; the steel frame and the steel walls constitute a closed water container; the external insulation material is applied to the outer surface of the steel walls to reduce heat loss; and the water within the reservoir is clean water with low mineralization.

[0038] a heating device, disposed in the underground water reservoir and electrically connected to the power supply device via the output-end cable, for heating the water in the reservoir to store thermal energy;

[0039] a heat exchange device, connected to the underground water reservoir, for utilizing the hot water in the underground water reservoir to generate organic working fluid steam;

[0040] A power generation device is communicated with the heat exchange device and is used to generate electricity using the organic working fluid steam.

[0041] The power supply device includes: output end cable, wind power generation and solar energy.

[0042] The power supply device utilizes wind power generation and solar energy through intelligent regulation and transmits the electricity to the electric heater in the underground reservoir through the output end cable.

[0043] Specifically, the power supply utilizes wind and solar power, transmitting it via output cables to an electric heater within the underground reservoir. This primarily aims to convert uneven and unstable electrical energy into effective heat, improving energy efficiency. The wind turbine generator transmits power to the substation via a box-type transformer, where it then transmits low voltage to the heating coil. After absorbing energy, the solar panels convert DC current into AC current via a grid-connected inverter, which then transmits it to the power transformer and ultimately to the electric heater.

[0044] The underground water reservoir is used to store energy, which is expressed in the form of changes in water temperature. It receives heat from a heating device to increase its temperature and transfers heat through a heat exchange device to cool it down. The heating device is used to heat the water in the underground water reservoir using the heat energy generated by the electric heater and store the heat energy. The heat exchange device is used to convert the thermal energy of the water in the underground water reservoir into the internal energy of the organic working fluid, producing high-temperature and high-pressure organic working fluid steam. The power generation device is used to use this steam to drive the steam turbine generator set in the power generation device to operate and generate electricity. The power generation device includes: an evaporator, a steam turbine generator set, a cooler, and a generator.

[0045] Optionally, the power generation device uses the organic working fluid extracted from the heat exchanger to generate high-temperature, high-pressure steam, which drives the turbine generator set. After the heat is transferred to the organic working fluid to generate high-temperature, high-pressure steam, the water temperature decreases and is returned to the underground reservoir. Geothermal power generation devices can generate electricity in four ways: dry steam generation, flash evaporation, dual-fluid generation, and full-flow generation. This technology selects the dual-fluid generation method based on the temperature of the heat exchange medium.

[0046] like Figure 2 As shown, this embodiment constructs an artificial geothermal storage body, that is, an underground water reservoir. Since the construction of the underground reservoir is only the reservoir body components and the water body in the reservoir, and the top is only 2m deep from the ground surface. The reservoir body components are only composed of the reservoir body steel skeleton, steel walls and external insulation materials. The water body in the reservoir is a clean water body with low mineralization, which is completely different from the actual groundwater aquifer. Therefore, the present invention completely solves the problems of pipeline blockage caused by groundwater mineralization, non-closed heat loss of aquifers, and high costs of underground exploration and mining drilling. This embodiment innovatively proposes the concept of "artificial geothermal", and its function is to build an energy storage project based on the principle of geothermal power generation, to solve the power generation of wind and solar power peak and excess "abandoned power", and to form a solar-wind combined power generation system.

[0047] Furthermore, the construction requirements for the underground reservoir in this embodiment are as follows:

[0048] 1. The stability of the underground reservoir foundation. The selected location should be one with stable geological conditions and relatively intact bedrock;

[0049] 2. The solidity of the underground reservoir structure. The construction material must be steel, with a steel frame support;

[0050] 3. The overall thermal insulation of the underground reservoir. It is required that the underground reservoir be covered with thermal insulation materials;

[0051] 4. Modularization of underground water reservoir components: Electric heaters are required to be designed as independent modules to facilitate safe replacement.

[0052] As an optional implementation, this embodiment calculates the water requirement of the artificial geothermal power generation unit based on the geothermal power generation principle:

[0053] Q = Pt;

[0054] Q = mcΔTη;

[0055] m=ρV;

[0056] V = Pt / (ρcΔTη);

[0057] In the formula, Q represents heat, J; P represents installed capacity, W; t represents time, s; m represents mass, kg; c represents the specific heat capacity of water, which is 4.2×10 3 J / (kg·℃); ΔT is the temperature difference between the inlet and outlet of the heat exchanger, ℃; ρ is the density of water, which is 1000kg / m 3 ; η is the total conversion efficiency, %; V is the volume, m 3 .

[0058] Set the water inlet temperature (T in )=200℃, water outlet temperature (T out )=80℃,η=86.6%

[0059] Then: ΔT=T in -T out =120℃;

[0060] 1. Water requirement of 10MW unit.

[0061] Then: V = 10 × 10 6 W×3600s / (1000kg / m 3 ×4200J / (kg·℃)×120℃×86.6%)=82.48m 3 / h;

[0062] Daily: 82.48 × 24 = 1979.52 m 3 ,Right now:

[0063] Power generation target: 10MV thermal power generation unit, that is, the rated power generation capacity per hour is 10MW.

[0064] Calculation result: 10MW requires 82.48m3 of 200℃ water 3 / h, 1979.52m per day 3 Water reserve: approximately 2000m 3 Water reserve.

[0065] 2. Water demand of 50MW unit.

[0066] Power generation target: 50MW thermal power generation unit, that is, the rated power generation capacity is 50MW per hour.

[0067] Calculation result: 50MW requires 412.4m3 of 200℃ water 3 / h, 9897.6m per day 3 Water reserve, about 10000m 3 Water reserve.

[0068] Considering the actual energy storage requirements, the reserve water capacity is enlarged. For a 50MW thermal power generation unit, it is built to 20,000m 3 Underground reservoirs, or two 10,000m 3 Connectable underground water reservoir.

[0069] 3. Water demand of 100MW unit.

[0070] Theoretical calculations show that a 100MW thermal power generation unit needs to be built to 20,000m 3 Underground reservoir. However, considering the actual energy storage requirements, the reserve water capacity is increased by 1.5 times, which means that 30,000m3 of underground reservoir is needed. 3 Underground reservoir or three 10,000m 3 Connectable underground water reservoir.

[0071] As mentioned above, the excavation pit is 50m long, 40m wide and 10m deep, which is the size of a standard swimming pool on the plane. The top of the underground reservoir is 2m above the ground, and its water capacity is 50m×40m×8m=16000m 3 Two such large underground reservoirs can meet the water demand of a 100MW unit.

[0072] Furthermore, the implementation process of this embodiment is as follows:

[0073] 1. Build underground reservoirs and inject clean water with low mineralization into them;

[0074] First, based on the geological and topographical conditions, a site with stable geology and relatively intact bedrock was selected. A foundation pit 50m long, 40m wide, and 10m deep was excavated to construct the underground space. The geological reservoir was constructed of steel with insulation, with its upper portion 2m above the ground.

[0075] The construction area has the ability to generate solar or wind power, and the system can be used for peak shaving and valley filling of solar or wind power generation to store energy.

[0076] Construct an electric heating component cavity space in the underground space, pipes and interfaces for taking hot water and returning cold water, as well as temperature and pressure online monitoring equipment and interfaces, etc.

[0077] Inject low-mineralization clean water to form an underground reservoir.

[0078] 2. Obtain electricity from wind power and solar energy through intelligent control;

[0079] Underground reservoirs are built for energy storage, serving as a complementary project for wind and solar power. Specifically, when solar or wind power generation is in excess or curtailed, intelligent control utilizes this electricity to heat the underground reservoir water. When solar or wind power generation is insufficient, hot water from the underground reservoir is used for power generation. This allows hot water generation from the underground reservoir to serve as a peak-shaving and valley-filling storage for solar or wind power generation, generating a stable current for transmission to the grid. Intelligent control plays a leading role in this process, determining the use of hot water heating and power generation in the underground reservoir based on peaks and valleys in solar or wind power generation.

[0080] 3. Heat the water in the underground reservoir through electric heaters to store thermal energy;

[0081] The intelligent control system determines whether to electrically heat the water in the underground reservoir. When electrically heated, the water temperature in the underground reservoir increases, which means that the energy storage increases.

[0082] 4. Convert the stored thermal energy into the internal energy of the organic working fluid to obtain high-temperature and high-pressure steam;

[0083] Intelligent control determines whether to use the underground reservoir's hot water for power generation. When power generation is required, the cold water return pump activates to circulate the underground reservoir's hot water into the heat exchange chamber, and the intermediate fluid booster pump activates to force the intermediate fluid into the heat exchange pipe. This process cools the underground reservoir water, transferring its energy to the intermediate fluid.

[0084] 5. The steam-driven turbine generator set in the power generation device is operated to generate electricity, thereby realizing solar-wind combined power generation with artificial geothermal energy storage.

[0085] When the high-temperature, high-pressure intermediate steam drives the turbine and generates electricity, it completes the process of converting thermal energy into kinetic energy and kinetic energy into electrical energy. This electricity supplements the insufficient solar or wind power generation, truly achieving stable power transmission, that is, realizing the solar-wind combined power generation of artificial geothermal energy storage.

[0086] like Figure 3 As shown, this embodiment also provides an artificial geothermal energy storage and solar-wind combined power generation system, including:

[0087] Step 100: Using a power supply device, the electric energy generated by wind power generation and / or solar power generation is transmitted to a heating device via an output cable. The heating device electrically heats the clean water with low mineralization in the underground reservoir to store thermal energy.

[0088] Step 200: When electrical energy needs to be output, hot water in the underground reservoir is exchanged with the organic working fluid through a heat exchange device to generate organic working fluid steam;

[0089] Step 300: delivering the organic working fluid steam to the power generation device to drive the power generation device to generate electricity;

[0090] Step 400: The water with a lowered temperature after heat exchange flows back to the underground reservoir, and the organic working fluid after doing work is cooled and recovered to form a water circulation and a working fluid circulation.

[0091] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. The methods disclosed in the embodiments are described briefly because they correspond to the systems disclosed in the embodiments. For relevant parts, refer to the description of the systems.

[0092] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. An artificial geothermal energy storage and solar-wind combined power generation system, characterized in that: include: Power supply devices, heating devices, underground water reservoirs, heat exchange devices and power generation devices; A power supply device for transmitting electric energy generated by wind power generation and / or solar power generation via an output end cable; An underground water reservoir comprises a steel frame, steel walls, external insulation material, and water within the reservoir; the steel frame and the steel walls constitute a closed water container; the external insulation material is applied to the outer surface of the steel walls to reduce heat loss; and the water within the reservoir is clean water with low mineralization. a heating device, disposed in the underground water reservoir and electrically connected to the power supply device via the output-end cable, for heating the water in the reservoir to store thermal energy; a heat exchange device, connected to the underground water reservoir, for utilizing the hot water in the underground water reservoir to generate organic working fluid steam; A power generation device is communicated with the heat exchange device and is used to generate electricity using the organic working fluid steam.

2. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1 is characterized in that: The top of the underground reservoir is 2m from the ground surface.

3. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1 is characterized in that: The power supply device is controlled by preset intelligent control instructions to supply power to the heating device when wind energy and / or solar energy have peak power or abandoned power, so as to realize energy storage scheduling of renewable energy to reduce peak power and fill valley power.

4. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1, characterized in that: The underground reservoir is located in an area with stable geological conditions and intact bedrock, and is constructed by excavating a foundation pit with a length of 50m, a width of 40m and a depth of 10m.

5. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1 is characterized in that: When the target installed capacity is 50MW, the effective volume of the underground reservoir is 20,000m 3 .

6. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1, characterized in that: The underground reservoir is provided with a temperature and pressure online monitoring interface; the temperature and pressure online monitoring interface is used to collect monitoring data and upload the monitoring data.

7. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1, characterized in that: The electric heater of the heating device is designed as an independent detachable module; when the independent detachable module is pulled out, automatic power-off protection is triggered, so that the electric heater can be safely replaced without stopping the water supply of the underground reservoir.

8. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 1, characterized in that: The heat exchange device includes a heat exchange cavity, a cold water return pump, an organic working fluid booster pump, and an organic working fluid heat-increasing pipe arranged in the heat exchange cavity; wherein, the outlet of the cold water return pump is connected to the hot water inlet of the heat exchange cavity, and is used to transport the hot water from the underground water reservoir to the heat exchange cavity; the organic working fluid booster pump drives the organic working fluid to flow through the organic working fluid heat-increasing pipe and exchange heat with the hot water to generate high-temperature and high-pressure organic working fluid steam.

9. The artificial geothermal energy storage and solar-wind combined power generation system according to claim 8, characterized in that: The outlet of the cold water return pump is connected to the return cold water inlet of the underground water reservoir, so that the low-temperature water after heat exchange flows back to the underground water reservoir, forming a closed water cycle to maintain the water level in the underground water reservoir.

10. An artificial geothermal energy storage and solar-wind combined power generation method, characterized in that: include: The power supply device transmits the electric energy generated by wind power generation and / or solar power generation to the heating device via the output end cable, and the heating device electrically heats the clean water with low mineralization in the underground reservoir to store thermal energy; When electrical energy needs to be output, the hot water in the underground reservoir is exchanged with the organic working fluid through the heat exchange device to generate organic working fluid steam; transporting the organic working fluid steam to a power generation device to drive the power generation device to generate electricity; The water with lowered temperature after heat exchange flows back to the underground reservoir, and the organic working fluid after doing work is cooled and recovered to form a water cycle and a working fluid cycle.

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