CN115013269B - Solar-assisted intermediate-deep geothermal heat pipe energy system and control method thereof - Google Patents

Abstract

The invention provides a solar-assisted mid-deep geothermal heat pipe energy system and a control method thereof, belonging to the technical field of mid-deep geothermal heat pipe energy; the technical problem to be solved is to provide an improvement in the hardware structure of a solar-assisted mid-deep geothermal heat pipe energy system ; The technical solution adopted to solve the above technical problems is: including a cold working medium tank, a hot working medium tank, a solar heat exchange branch, a middle-deep geothermal heat exchange main road, and the solar heat exchange branch is arranged in the middle and deep geothermal heat exchange main road It is located at the upper end of the ground part, wherein the connecting pipes between the cold working medium tank and the hot working medium tank respectively form a circulating pipeline system with the solar heat exchange branch and the middle and deep geothermal heat exchange main road. The heat supply system is also connected between the mass tanks through pipes; the invention is applied to the energy system of the middle and deep geothermal heat pipe.

Description

A solar-assisted mid-deep geothermal heat pipe energy system and its control method

technical field

The invention provides a solar-assisted mid-deep geothermal heat pipe energy system and a control method thereof, belonging to the technical field of mid-deep geothermal heat pipe energy.

Background technique

The mid-deep buried pipe heat pump heating system is a new way of utilizing geothermal energy. Its outstanding feature is that the depth of the borehole is generally 1000m-3000m. It has good heat exchange and heat storage performance in winter, and is suitable for winter heating in cold northern regions. Or the use of buildings with small buried pipe space.

The existing mid-deep geothermal buried pipe heat pump system has the following defects:

① The heat exchange efficiency of buried pipes needs to be improved;

② Unable to make reasonable use of free solar thermal energy and further reduce carbon emissions;

③ The selection of the system working fluid is limited by the reverse Carnot cycle, which cannot generate high-temperature heat energy output above 200°C, and cannot be extended to steam turbine power generation;

④ The control and guarantee design of cogeneration needs to be improved, and it is necessary to increase the technical design of peak shaving energy storage, non-stop operation during system maintenance, and improving the safety and stability of system control.

Therefore, the present invention proposes a solar-assisted mid-deep geothermal heat pipe energy system and a control method thereof, which simultaneously solves the above four problems, does not require additional power consumption, and can fully utilize free solar light and heat. The system components of the present invention all use the existing mature technologies and products, the technical feasibility is strong, and the safety and stability of the product functions are better.

SUMMARY OF THE INVENTION

In order to overcome the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide an improvement in the hardware structure of a solar-assisted mid-deep geothermal heat pipe energy system.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a solar energy-assisted mid-deep geothermal heat pipe energy system, comprising a cold working medium tank, a hot working medium tank, a solar heat exchange branch, and a middle and deep geothermal heat exchange main circuit, The solar heat exchange branch is arranged at the upper end of the middle and deep geothermal heat exchange main road at the ground part, wherein the connecting pipes between the cold working medium tank and the hot working medium tank are respectively formed with the solar heat exchange branch and the middle and deep geothermal heat exchange main road. In the circulation pipeline system, the cold working medium tank and the hot working medium tank are also connected to the heating system through pipes.

The middle-deep geothermal heat exchange main circuit includes a geothermal heat pipe, a geothermal heat pipe heat exchange fin, a geothermal heat exchanger, and a geothermal heat exchange temperature sensor arranged in the middle-deep layer and extending to the ground, wherein the middle of the geothermal heat pipe is located in the middle-deep layer. There is a geothermal heat pipe evaporation section, and a geothermal heat pipe condensation section is arranged on the ground in the middle of the geothermal heat pipe. The main outlet of the cold working medium tank is connected to a first main pipe, and the first main pipe is connected to the geothermal heat exchange through the first branch pipe. The input end of the heat exchanger, the output end of the geothermal heat exchanger is connected to the general inlet of the hot working medium tank through the second general pipeline, and the first outlet of the hot working medium tank is connected to the first inlet of the cold working medium tank through the third general pipeline ;

A working medium pump is arranged on the first main pipeline, a geothermal heat exchange regulating valve is arranged on the first branch pipeline, and a geothermal heat exchange temperature sensor is arranged on the ground output end of the second main pipeline close to the geothermal heat exchanger , a working medium bypass valve is arranged on the third main pipeline.

The solar heat exchange branch includes a solar heat exchange platform, the solar heat exchange platform is placed on the ground part of the geothermal heat pipe, and the solar heat exchange platform is provided with a solar heat pipe heat exchanger, a solar heat pipe, and a solar heat pipe heat exchanger. Sensor, the first main pipe is connected to one end of the solar heat pipe through a second branch pipe, the other end of the solar heat pipe is connected to the thermal medium tank through the second general pipe, and the second branch pipe is provided with a solar heat exchange regulating valve .

The heating system includes a steam turbine generator, a heating phase change heat storage module, and a heat supply heat exchanger. The steam turbine generator is arranged on the fourth main pipe connecting the cold working medium tank and the hot working medium tank. The fourth main pipe is connected to the heat supply phase change heat storage module through the third branch pipe, the heat supply phase change heat storage module is connected to the heat supply heat exchanger, and the heat supply heat exchanger is connected to the heat exchange pipeline;

A steam turbine generator power regulating valve is arranged on the fourth main pipe near the end of the cold working medium tank, and a heating power regulating valve is arranged on the third branch pipe near the end of the cold working medium tank.

The hot working medium tank is provided with a working medium tank phase change heat storage module;

The materials of the working fluid tank phase change heat storage module and the heating phase change heat storage module are all ternary molten salts, that is, mixed nitrates with a mass fraction of 53% potassium nitrate + 40% sodium nitrite + 7% sodium nitrate. , its melting point is 142 °C, and its vaporization point is 500 °C.

The part of the geothermal heat pipe in contact with the ground is provided with a pressure-resistant sealing protective layer and a ground hardening protective layer.

A control method for a solar-assisted mid-deep geothermal heat pipe energy system, using the solar-assisted mid-deep geothermal heat pipe energy system, includes the following steps:

As a conventional cogeneration control steps are as follows:

The working fluid in the cold working fluid tank is driven by the working fluid pump for system circulation, and the opening degrees of the geothermal heat exchange regulating valve and the solar heat exchange regulating valve are adjusted in proportion to the parameters of the geothermal heat exchange temperature sensor and the temperature sensor of the solar heat pipe heat exchanger respectively. , to control the flow of the working fluid in the cold working fluid tank through the solar heat exchange branch and the geothermal heat pipe;

After the working fluid in the cold working fluid tank is heated, it enters the hot working fluid tank for voltage stabilization and storage. After that, the steam turbine generator heats the high-pressure steam to drive the generator to generate electricity, and the other way enters the heating phase change heat storage module as an auxiliary The flow of the steam turbine generator participates in thermal energy regulation, and the opening of the steam turbine generator power regulating valve and the heating power regulating valve is adjusted in proportion to the output power of the steam turbine generator;

The control logic of the geothermal heat exchange control valve and the solar heat exchange control valve is as follows:

(1) First, protect the safe and stable operation of the working fluid pump. The total opening cross-sectional area of the geothermal heat exchange regulating valve and the solar heat exchange regulating valve is always equal to the cross-sectional area of the outlet pipeline of the working fluid pump, and the initial opening degree of the geothermal heat exchange regulating valve Φ ₁ is the cross-sectional area of the outlet pipeline of the working fluid pump, and the solar heat exchange regulating valve is initially fully closed;

(2) The opening degree of the geothermal heat exchange regulating valve Φ ₃ =a(T _s -T ₁₁ ) ² +b(T _s -T ₁₁ )+c, where T _s is the set working value of the geothermal heat exchanger outlet. The temperature of the material, _T11 is the measured temperature of the working medium at the outlet of the geothermal heat exchanger, which is fed back at regular intervals, a, b, and c are proportional constants, which vary according to the equipment model and the geothermal temperature range;

(3) The opening degree of the solar heat exchange regulating valve Φ ₄ =Φ ₁ -Φ ₃ , where Φ ₁ is the cross-sectional area of the outlet pipe of the working fluid pump, ensuring that Φ ₁ ≥Φ ₃ ;

The control logic of the steam turbine generator power regulating valve and the heating power regulating valve is as follows:

(1) The initial opening of the steam turbine generator power regulating valve is Φ ₂ , and the heating power regulating valve is initially fully closed;

(2) The opening degree of the steam turbine generator power regulating valve Φ ₂₁ =e(P _s -P ₂₂ ) ² +f(P _s -P ₂₂ )+g, where P _s is the rated output power of the generator, and P ₂₂ It is the measured output power of the generator, which is fed back at regular intervals. e, f, and g are proportional constants, which vary according to the equipment model and the geothermal temperature range;

(3) The opening degree of the heating power regulating valve Φ ₂₃ =Φ ₂ -Φ ₂₁ , where Φ ₂ is the cross-sectional area of the outlet pipe of the thermal fluid tank, ensuring that Φ ₂ ≥Φ ₂₁ .

The working medium in the geothermal heat pipe and the cold working medium tank adopts naphthalene, the chemical formula is C ₁₀ H ₈ , the melting point: 80~82°C under one atmospheric pressure, the boiling point: 217.9°C, and the critical temperature: 475.2°C;

The working fluid of the solar heat pipe adopts methanol, the chemical formula is CH ₃ OH, the melting point: -97.8°C, the boiling point: 64.7°C, and the critical temperature: 240°C under one atmospheric pressure;

The structure of the solar heat pipe is, from the outside to the inside, the high light-transmitting resin sheath, the graphene solar energy absorption coating + the copper heat pipe, and the structure of the solar heat pipe heat exchanger is the high light-transmitting resin sheath from the outside to the inside. Cover, graphene solar absorption coating + copper heat exchanger, the naphthalene transported by the pipeline not only absorbs the heat released by the condensing section of the solar heat pipe in the solar heat pipe heat exchanger, but also absorbs the solar light absorbed by the shell of the solar heat pipe heat exchanger hot.

A control method for a solar-assisted mid-deep geothermal heat pipe energy system, using the solar-assisted mid-deep geothermal heat pipe energy system, includes the following steps:

The control steps of peak shaving energy storage as cogeneration are as follows:

When the steam turbine generator cannot meet the power load of downstream users under the current working conditions or rated output power, the peak regulation function of cogeneration is manually controlled and activated;

First, verify that the geothermal heat exchange regulating valve is fully open, the solar heat exchange regulating valve is fully closed, the steam turbine generator power regulating valve is fully open, and the heating power regulating valve is fully closed, so that the system pipeline is switched to the function of full power supply;

Turn on the phase change heat storage module of the working fluid tank, so that the phase change heat storage module of the working fluid tank above 250 ℃ fully heats the working fluid and improves the output power of the steam turbine generator;

When the temperature of the working fluid in the working fluid tank is above 200℃, the working fluid of the working fluid tank phase change heat storage module is heated to melt and keep warm for storage. It is enabled when the peak shaving function of the product is enabled;

When the power peak shaving is completed or the temperature of the phase change heat storage module of the working fluid tank drops to 150°C and below for the set time, the system resets to the working state before the peak shaving function.

The working medium in the geothermal heat pipe and the cold working medium tank adopts naphthalene, the chemical formula is C ₁₀ H ₈ , the melting point: 80~82°C under one atmospheric pressure, the boiling point: 217.9°C, and the critical temperature: 475.2°C;

The working fluid of the solar heat pipe adopts methanol, the chemical formula is CH ₃ OH, the melting point: -97.8°C, the boiling point: 64.7°C, and the critical temperature: 240°C under one atmospheric pressure;

The structure of the solar heat pipe is, from the outside to the inside, the high light-transmitting resin sheath, the graphene solar energy absorption coating + the copper heat pipe, and the structure of the solar heat pipe heat exchanger is the high light-transmitting resin sheath from the outside to the inside. Cover, graphene solar absorption coating + copper heat exchanger, the naphthalene transported by the pipeline not only absorbs the heat released by the condensing section of the solar heat pipe in the solar heat pipe heat exchanger, but also absorbs the solar light absorbed by the shell of the solar heat pipe heat exchanger hot.

The beneficial effects possessed by the present invention relative to the prior art are:

① The heat exchange efficiency of the geothermal heat pipe reaches more than 98%, no additional power is required, the fluid resistance is small, the structure is simple, the processing is easy, the cost is low, and the work is reliable; the heat exchange efficiency of the general buried pipe heat exchanger is about 95%.

② Make full use of free solar light and heat to further reduce carbon emissions.

③ The selection of the working fluid of the system is flexible, and the working fluid suitable for the melting point, boiling point and critical temperature can be selected according to different ground temperature intervals, and it can be extended to steam turbine power generation and heat supply.

④ Improve the control and guarantee design of cogeneration, increase the technical design of peak shaving energy storage, non-stop operation during system maintenance, and improve the safety and stability of system control.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings:

Fig. 1 is the structural representation of the system of the present invention;

In the picture: 1. Cold working fluid tank; 2. Working fluid pump; 3. Geothermal heat exchange regulating valve; 4. Solar heat exchange regulating valve; 5. Solar heat pipe heat exchanger; 6. Solar heat pipe; 7. Solar heat pipe exchange Heater temperature sensor; 8. Solar heat exchange platform; 9. Geothermal heat pipe heat exchange fins; 10. Geothermal heat exchanger; 11. Geothermal heat exchange temperature sensor; 12. Geothermal heat pipe condensation section; 13. Compression sealing protective layer ; 14. Ground hardening protective layer; 15. Evaporation section of geothermal heat pipe; 16. Geothermal heat pipe; 17. Middle-deep formation; 18. Thermal working fluid tank; 21. Steam turbine generator power regulating valve; 22. Steam turbine generator; 23. Heating power regulating valve; 24. Heating phase change heat storage module; 25. Heating heat exchanger; 26. Heating pipeline;

100 is the first general pipe, 101 is the first branch pipe, 102 is the second general pipe, 103 is the third general pipe, 104 is the second branch pipe, 105 is the fourth general pipe, and 106 is the third branch pipe.

Detailed ways

As shown in FIG. 1, the present invention proposes a solar-assisted mid-deep geothermal heat pipe energy system, including a cold working medium tank 1, a hot working medium tank 10, a solar heat exchange branch, a middle and deep geothermal heat exchange main circuit, and a solar energy exchange The hot branch is arranged at the upper end of the ground part of the middle-deep geothermal heat exchange main road, wherein the connecting pipes between the cold working medium tank 1 and the hot working medium tank 18 are respectively formed with the solar heat exchange branch and the middle and deep geothermal heat exchange main circuit. In the circulation pipeline system, the cold working medium tank 1 and the hot working medium tank 18 are also connected to the heating system through pipes.

The middle-deep geothermal heat exchange main circuit includes a geothermal heat pipe 16, a geothermal heat pipe heat exchange fin 9, and a geothermal heat exchanger 10, which are arranged in the middle-deep layer and extend to the ground, wherein the geothermal heat pipe 16 is located in the middle and deep layer. The geothermal heat pipe evaporation section 15, the geothermal heat pipe condensation section 12 is located on the ground in the middle of the geothermal heat pipe 16, the main outlet of the cold working medium tank 1 is connected to the first main pipe 100, and the first main pipe 100 passes through the first branch pipe 101 is connected to the input end of the geothermal heat exchanger 10, and the output end of the geothermal heat exchanger 10 is connected to the main inlet of the thermal medium tank 18 through the second main pipe 102, and the first outlet of the thermal medium tank 18 passes through the third main pipe. The pipeline 103 is connected to the first inlet of the cold working medium tank 1;

The first main pipe 100 is provided with a working fluid pump 2 , the first branch pipe 101 is provided with a geothermal heat exchange regulating valve 3 , and the second main pipe 102 is provided close to the ground output end of the geothermal heat exchanger 10 . There is a geothermal heat exchange temperature sensor 11 , and a working medium bypass valve 20 is arranged on the third main pipe 103 .

The solar heat exchange branch includes a solar heat exchange platform 8, the solar heat exchange platform 8 is placed on the ground part of the geothermal heat pipe 16, and the solar heat exchange platform 8 is provided with a solar heat pipe heat exchanger 5, a solar heat pipe 6, The solar heat pipe heat exchanger temperature sensor 7, the first main pipe 100 is connected to one end of the solar heat pipe 6 through the second branch pipe 104, and the other end of the solar heat pipe 6 is connected to the thermal medium tank 18 through the second main pipe 102, so The second branch pipe 104 is provided with a solar heat exchange regulating valve 4 .

The heating system includes a steam turbine generator 22, a heating phase change heat storage module 24, and a heat supply heat exchanger 25. The steam turbine generator 22 is arranged in the connection between the cold working medium tank 1 and the hot working medium tank 18. On the fourth main pipe 105, the fourth main pipe 105 is connected to the heat supply phase change heat storage module 24 through the third branch pipe 106, and the heat supply phase change heat storage module 24 is connected to the heat supply heat exchanger 25 to supply heat The heat exchanger 25 is connected to the heat exchange pipeline 26;

The fourth main pipe 105 is provided with a steam turbine generator power regulating valve 21 near the first end of the cold working medium tank, and the third branch pipe 106 is provided with a heating power regulating valve 23 near the first end of the cold working medium tank.

A working medium tank phase change heat storage module 19 is arranged inside the hot working medium tank 18 .

The part of the geothermal heat pipe 16 in contact with the ground is provided with a pressure-resistant sealing protective layer 13 and a ground hardening protective layer 14 .

The working fluid of the geothermal heat pipe 16 and the cold working fluid tank 1 of the present invention is selected from naphthalene, the chemical formula is C ₁₀ H ₈ , the melting point: 80~82°C under one atmosphere, the boiling point: 217.9°C, and the critical temperature: 475.2°C, suitable for 200 The mid-deep geothermal temperature range of ~400℃. The stable physical and chemical properties of the single-component working fluid is conducive to the system to give full play to the design parameters and functions, and avoid the fluctuation of the physical and chemical properties of the working fluid caused by the easy change of the component ratio of the mixed working fluid, which may lead to the malfunction of the system.

The working medium of the solar heat pipe 6 of the present invention is methanol, the chemical formula is CH ₃ OH, the melting point is: -97.8°C, the boiling point: 64.7°C, and the critical temperature: 240°C under one atmospheric pressure, which is suitable for the solar thermal temperature range of about 100°C. , and take into account the winter outdoor antifreeze, free of manual maintenance. The structure of the solar heat pipe 6 is, from the outside to the inside, a high light-transmitting resin sheath, a graphene solar energy absorption coating + a copper heat pipe, and the solar radiation absorption rate reaches a maximum of more than 98%. The structure of the solar heat pipe heat exchanger 5 is, from the outside to the inside, a high light-transmitting resin sheath, a graphene solar energy absorption coating + a copper heat exchanger, and the naphthalene transported by the pipeline absorbs the solar heat pipe in the solar heat pipe heat exchanger 5. The condensation section of 6 releases heat, and absorbs the solar light and heat absorbed by the shell of the solar heat pipe heat exchanger 5 . The function of the solar heat exchange branch is to heat and preheat the shunted naphthalene, and the second is to provide heat for heating. The installation angle of the solar module platform 8 is the best azimuth angle and inclination angle of the local solar radiation receiving surface.

The materials of the working fluid tank phase change heat storage module 19 and the heating phase change heat storage module 24 of the present invention are ternary molten salt, that is, mixed nitric acid consisting of 53% potassium nitrate + 40% sodium nitrite + 7% sodium nitrate in mass fraction The salt has a melting point of 142°C and a vaporization point of 500°C.

The main functions realized by the system of the invention include: ① conventional cogeneration; ② peak shaving energy storage of combined heat and power; ③ non-stop operation during system maintenance;

① Conventional cogeneration: The working fluid pump 2 drives the naphthalene in the cold working fluid tank 1 to circulate the system, and the opening degrees of the geothermal heat exchange regulating valve 3 and the solar heat exchange regulating valve 4 are respectively in accordance with the geothermal heat exchange temperature sensor 11 and the solar energy The parameter ratio of the heat pipe heat exchanger temperature sensor 7 is adjusted to control the flow of naphthalene through the solar heat exchange branch and the geothermal heat pipe 16 . After the naphthalene is heated, it enters the thermal medium tank 18 for voltage stabilization and storage, and then enters the steam turbine generator 22 to heat the high-pressure water vapor to drive the generator to generate electricity, and the other way enters the heating phase change heat storage module 24 as an auxiliary flow rate and For thermal energy regulation, the opening degrees of the steam turbine generator power regulating valve 21 and the heating power regulating valve 23 are adjusted in proportion to the output power of the steam turbine generator 22 .

The control logic of the geothermal heat exchange control valve 3 and the solar heat exchange control valve 4: (1) First, protect the safe and stable operation of the working fluid pump 2, and the total opening cross-sectional area of the geothermal heat exchange control valve 3 and the solar heat exchange control valve 4 It is always equal to the cross-sectional area of the outlet pipeline of the working fluid pump 2, so that the output pressure of the working fluid pump 2 is kept stable and the pump body is safe. The initial opening of the geothermal heat exchange regulating valve 3 is Φ ₁ , and the solar heat exchange regulating valve 4 is initially fully closed. (2) The opening degree of the geothermal heat exchange regulating valve 3 Φ ₃ =a(T _s -T ₁₁ ) ² +b(T _s -T ₁₁ )+c, where T _s is the set outlet of the geothermal heat exchanger 10 The temperature of naphthalene, _T11 is the measured temperature of naphthalene at the outlet of the geothermal heat exchanger 10, which is fed back every 5min, a, b, and c are proportional constants, which vary according to the equipment model and the geothermal temperature range. (3) The opening degree of the solar heat exchange regulating valve 4 is Φ ₄ =Φ ₁ -Φ ₃ , where Φ ₁ is the cross-sectional area of the outlet pipeline of the working fluid pump 2 . It is guaranteed that Φ ₁ ≥Φ ₃ .

The control logic of the steam turbine generator power regulating valve 21 and the heating power regulating valve 23: (1) The initial opening of the steam turbine generator power regulating valve 21 is Φ ₂ , and the heating power regulating valve 23 is initially fully closed. (2) The opening degree of the steam turbine generator power regulating valve 21 Φ ₂₁ =e(P _s -P ₂₂ ) ² +f(P _s -P ₂₂ )+g, where P _s is the rated output power of the generator, and P ₂₂ is the measured output power of the generator, which is fed back every 5 minutes. e, f, and g are proportional constants, which vary according to the equipment model and the geothermal temperature range. (3) The opening degree of the heating power regulating valve 23 Φ ₂₃ =Φ ₂ −Φ ₂₁ , wherein, Φ ₂ is the cross-sectional area of the outlet pipeline of the thermal medium tank 18 . It is guaranteed that Φ ₂ ≥Φ ₂₁ .

② Peak shaving energy storage for cogeneration: under the normal operation of the system, the heating function can meet the user's thermal load. If the steam turbine generator 22 cannot meet the electric load of the downstream user under the current working condition or the rated output power, the peak shaving function of the combined heat and power generation is manually controlled and activated. First, check to confirm that the geothermal heat exchange regulating valve 3 is fully open, the solar heat exchange regulating valve 4 is fully closed, the steam turbine generator power regulating valve 21 is fully open, and the heating power regulating valve 23 is fully closed, so that the system pipeline is switched to full power supply. Function. The phase change heat storage module 19 of the working fluid tank is turned on, so that the phase change heat storage module 19 with a temperature above 250° C. fully heats naphthalene, and the output power of the steam turbine generator 22 is increased. The material of the phase change heat storage module 19 of the working medium tank is a ternary molten salt, that is, a mixed nitrate composed of 53% potassium nitrate + 40% sodium nitrite + 7% sodium nitrate with a mass fraction of 53% potassium nitrate + 7% sodium nitrate, the melting point is 142 ° C, the gasification point 500°C, suitable for mid-deep geothermal power generation applications at 200~400°C. The phase change heat storage module 19 of the working fluid tank heats the ternary molten salt when the temperature of naphthalene in the daily hot working fluid tank 18 is above 200°C to melt it and store it for heat preservation. When the peak regulation function of cogeneration is manually controlled and activated enable. When the power peak shaving is completed or the temperature of the phase change heat storage module 19 of the working fluid tank drops to 150°C or below for 30 minutes, the system resets to the working state before the peak shaving function. If the power peak shaving is completed, the reset will be manually controlled; if the temperature of the phase change heat storage module 19 of the working fluid tank drops to 150°C or below and maintained for 30 minutes, the system will automatically reset.

③ The system does not stop running during maintenance: when 2~17 are damaged and need to be repaired, close the geothermal heat exchange regulating valve 3 or the solar heat exchange regulating valve 4 or the geothermal heat exchange regulating valve 3 and the solar heat exchange regulating valve 4, combined with the damage Component maintenance to ensure that the hot and cold working fluid tanks are connected through the cogeneration equipment. The phase change heat storage module 19 of the working medium tank is turned on to heat the naphthalene in the hot working medium tank 18 . Continue to generate electricity and heat while maintaining equipment. If the hot and cold working medium tanks are only connected through the cogeneration equipment, then in the later period of the maintenance of this function, the pressure in the cold working medium tank 1 will gradually increase, and the bypass valve 20 of the working medium tank will be opened to balance the cold and hot working medium tanks. internal pressure to ensure the safety of power generation. During the pressure balancing process, until the output power of the steam turbine generator 22 drops to 20% of the rated output power, close the bypass valve 20 of the working medium tank to stop this function, and ensure that the time interval between restarting the system and returning to normal operation is within 1.5 hours.

④ Technical design of system regulation safety and stability: (1) The arrangement position of the working fluid pump 2 is shown in Figure 1, so that the pump head is used to directly overcome the interior of the geothermal heat exchanger 10 and the solar heat pipe heat exchanger 5 Flow resistance, stable and efficient. (2) The arrangement of the geothermal heat exchange regulating valve 3 and the solar heat exchange regulating valve 4 is shown in Figure 1. Adjusting the flow distribution ratio in the low temperature and low pressure stage of naphthalene is beneficial to protect the safety of the regulating valve body and prolong the service life. The functional parameter adjustment compatibility of the working fluid pump 2 is good. (3) The arrangement positions of the steam turbine generator power regulating valve 21 and the heating power regulating valve 23 are shown in Figure 1, and the design intention is the same as that of the geothermal heat exchange regulating valve 3 and the solar heat exchange regulating valve 4, that is, in the naphthalene The flow distribution ratio is adjusted in the low temperature and low pressure stage, which is beneficial to protect the safety of the regulating valve body and prolong the service life. (4) The arrangement position of the bypass valve 20 of the working fluid tank is shown in Figure 1. It is used for the non-stop function during system maintenance, and it can also be used for the internal pressure of the cold working fluid tank 1 and the hot working fluid tank 18 during maintenance. Safe and stable. (5) The solar heat pipe heat exchanger temperature sensor 7 and the geothermal heat exchange temperature sensor 11 have the function of pipeline self-checking. The leakage of the system pipeline may mainly occur from the cold working medium tank 1 to the geothermal heat pipe 16 and the solar heat pipe heat exchanger 5. Pipeline section. For the solar heat pipe heat exchanger temperature sensor 7, if T ₀ is measured when the system is initially started during the day, if the measured value of the solar heat pipe heat exchanger temperature sensor 7 reaches T ₀ +10°C within 30 minutes (when the solar radiation intensity < 120W /m ² ), or if the measured value of the solar heat pipe heat exchanger temperature sensor 7 reaches T ₀ +25°C within 30 minutes (when 120W/m ² ≤ solar radiation intensity <300W/m ² ), or within 30 minutes if the solar heat pipe If the measured value of the heat exchanger temperature sensor 7 reaches T ₀ +35°C (when 300W/m ² ≤ solar radiation intensity), the solar heat exchange branch may leak or be blocked, and it is necessary to check for leaks; During normal days, if the measured value of the temperature sensor 7 of the solar heat pipe heat exchanger rises by 10°C within 30 minutes (when the solar radiation intensity is less than 120W/m ² ), or the measured value of the temperature sensor 7 of the solar heat pipe heat exchanger rises within 30 minutes. 25°C higher (when 120W/m ² ≤ solar radiation intensity <300W/m ² ), or the measured value of the temperature sensor 7 of the solar heat pipe heat exchanger within 30min rises by 35°C (when 300W/m ² ≤ solar radiation intensity), Then the solar heat exchange branch may leak, which needs to be checked for leaks. For the geothermal heat exchange temperature sensor 11, if the measured value T ₀₀ of the system is initially started, if the measured value of the geothermal heat exchange temperature sensor 11 does not reach T ₀₀ +100°C within 1.5 hours, there may be leakage or pipeline blockage, which needs to be checked. ; If the feedback value of the geothermal heat exchange temperature sensor 11 drops by 60°C within 1.5 hours during the normal operation of the system, there may be leakage or pipeline blockage, which needs to be checked.

The geothermal heat pipe 16 of the present invention adopts a gravity heat pipe, and the academic name of the gravity heat pipe is called "two-phase closed thermosiphon", or "thermosiphon" for short. The inside of the copper tube is evacuated and then filled with a certain amount of working medium. The working medium circulates repeatedly inside the evaporation-condensation phase change process, and continuously transfers the heat from the evaporation section to the condensation section, thereby completing the heat transfer process of heat transfer. . The basic working principle of the gravity heat pipe is as follows. The inside of the welded and sealed tube shell is evacuated by a vacuum unit, and then an appropriate amount of working fluid is installed, and then cold welding and ultrasonic welding are carried out to seal. The complete gravity heat pipe is divided into three parts: evaporation section (heating section), condensation section (cooling section) and adiabatic section. When the working fluid is heated in the evaporation section of the gravity heat pipe, it evaporates and gasifies, and at the same time absorbs a large amount of latent heat of vaporization. The working medium flows to the evaporation section along the tube wall by gravity. Such a constant high-speed cycle, heat is transferred from one end of the gravity heat pipe to the other. The biggest feature of the gravity heat pipe is that there is no liquid absorption core inside the cavity, so the gravity heat pipe has many advantages such as simple structure, easy processing, low cost, and reliable operation. The working fluid selection of gravity heat pipe can flexibly adjust the working fluid with boiling point, melting point and critical point suitable for the corresponding temperature range according to the difference of the working environment temperature of the heat pipe.

Regarding the specific structure of the present invention, it should be noted that the connection relationship between the various component modules adopted in the present invention is determined and achievable. Technical effect, and based on the premise of not relying on the execution of the corresponding software program to solve the technical problem proposed by the present invention, the components, modules, and the model and connection method of the specific components appearing in the present invention belong to the field unless specifically described. Existing technologies such as published patents, published journal papers, or common knowledge that can be obtained by technical personnel before the application date, do not need to be repeated, so that the technical solution provided in this case is clear, complete and achievable, and can be based on this technology. means to reproduce or obtain the corresponding physical product.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims (4)

1. A control method for a solar-assisted mid-deep geothermal heat pipe energy system, using a solar-assisted mid-deep geothermal heat pipe energy system, the system comprising a cold working medium tank, a hot working medium tank, a solar heat exchange branch, a middle and deep geothermal heat exchange The heat main circuit and the solar heat exchange branch are arranged at the upper end of the middle and deep geothermal heat exchange main road, and the connecting pipes between the cold working medium tank and the hot working medium tank are respectively connected with the solar heat exchange branch and the middle and deep geothermal heat exchange. The hot main circuit forms a circulating pipeline system, and the cold working medium tank and the hot working medium tank are also connected to the heating system through pipes; The middle-deep geothermal heat exchange main circuit includes a geothermal heat pipe, a geothermal heat pipe heat exchange fin, and a geothermal heat exchanger, which are arranged in the middle-deep layer and extend to the ground, wherein the geothermal heat pipe is located in the middle and deep layer and is provided with a geothermal heat pipe evaporation section. , the middle of the geothermal heat pipe is located on the ground with a condensing section of the geothermal heat pipe, the general outlet of the cold working medium tank is connected to the first main pipe, and the first main pipe is connected to the input end of the geothermal heat exchanger through the first sub-pipeline. The output end of the heat exchanger is connected to the general inlet of the hot working medium tank through the second general pipeline, and the first outlet of the hot working medium tank is connected to the first inlet of the cold working medium tank through the third general pipeline; A working medium pump is arranged on the first main pipeline, a geothermal heat exchange regulating valve is arranged on the first branch pipeline, and a geothermal heat exchange temperature sensor is arranged on the ground output end of the second main pipeline close to the geothermal heat exchanger , the third main pipeline is provided with a working medium bypass valve; The solar heat exchange branch includes a solar heat exchange platform, the solar heat exchange platform is placed on the ground part of the geothermal heat pipe, and the solar heat exchange platform is provided with a solar heat pipe heat exchanger, a solar heat pipe, and a solar heat pipe heat exchanger. Sensor, the first main pipe is connected to one end of the solar heat pipe through a second branch pipe, the other end of the solar heat pipe is connected to the thermal medium tank through the second general pipe, and the second branch pipe is provided with a solar heat exchange regulating valve ; The heating system includes a steam turbine generator, a heating phase change heat storage module, and a heat supply heat exchanger. The steam turbine generator is arranged on the fourth main pipe connecting the cold working medium tank and the hot working medium tank. The fourth main pipe is connected to the heat supply phase change heat storage module through the third branch pipe, the heat supply phase change heat storage module is connected to the heat supply heat exchanger, and the heat supply heat exchanger is connected to the heat exchange pipeline; A steam turbine generator power regulating valve is arranged on the fourth main pipe near the end of the cold working medium tank, and a heating power regulating valve is arranged on the third branch pipe near the end of the cold working medium tank; It is characterized in that: comprise the following steps: As a conventional cogeneration control steps are as follows: The working fluid in the cold working fluid tank is driven by the working fluid pump for system circulation, and the opening degrees of the geothermal heat exchange regulating valve and the solar heat exchange regulating valve are adjusted in proportion to the parameters of the geothermal heat exchange temperature sensor and the temperature sensor of the solar heat pipe heat exchanger respectively. , to control the flow of the working fluid in the cold working fluid tank through the solar heat exchange branch and the geothermal heat pipe; After the working fluid in the cold working fluid tank is heated, it enters the hot working fluid tank for voltage stabilization and storage. After that, the steam turbine generator heats the high-pressure steam to drive the generator to generate electricity, and the other way enters the heating phase change heat storage module as an auxiliary The flow of the steam turbine generator participates in thermal energy regulation, and the opening of the steam turbine generator power regulating valve and the heating power regulating valve is adjusted in proportion to the output power of the steam turbine generator; The control logic of the geothermal heat exchange control valve and the solar heat exchange control valve is as follows: (1) First, protect the safe and stable operation of the working fluid pump. The total opening cross-sectional area of the geothermal heat exchange regulating valve and the solar heat exchange regulating valve is always equal to the cross-sectional area of the outlet pipeline of the working fluid pump, and the initial opening degree of the geothermal heat exchange regulating valve Φ ₁ is the cross-sectional area of the outlet pipeline of the working fluid pump, and the solar heat exchange regulating valve is initially fully closed; (2) The opening degree of the geothermal heat exchange regulating valve Φ ₃ =a(T _s -T ₁₁ ) ² +b(T _s -T ₁₁ )+c, where T _s is the set working value of the geothermal heat exchanger outlet. The temperature of the material, _T11 is the measured temperature of the working medium at the outlet of the geothermal heat exchanger, which is fed back at regular intervals, a, b, and c are proportional constants, which vary according to the equipment model and the geothermal temperature range; (3) The opening degree of the solar heat exchange regulating valve Φ ₄ =Φ ₁ -Φ ₃ , where Φ ₁ is the cross-sectional area of the outlet pipe of the working fluid pump, ensuring that Φ ₁ ≥Φ ₃ ; The control logic of the steam turbine generator power regulating valve and the heating power regulating valve is as follows: (1) The initial opening of the steam turbine generator power regulating valve is Φ ₂ , and the heating power regulating valve is initially fully closed; (2) The opening degree of the steam turbine generator power regulating valve Φ ₂₁ =e(P _s -P ₂₂ ) ² +f(P _s -P ₂₂ )+g, where P _s is the rated output power of the generator, and P ₂₂ It is the measured output power of the generator, which is fed back at regular intervals. e, f, and g are proportional constants, which vary according to the equipment model and the geothermal temperature range; (3) The opening degree of the heating power regulating valve Φ ₂₃ =Φ ₂ -Φ ₂₁ , where Φ ₂ is the cross-sectional area of the outlet pipe of the thermal fluid tank, ensuring that Φ ₂ ≥Φ ₂₁ . 2. The control method of a solar-assisted mid-deep geothermal heat pipe energy system according to claim 1, wherein the working medium in the geothermal heat pipe and the cold working medium tank adopts naphthalene, and the chemical formula is C ₁₀ H ₈ , Melting point: 80~82℃ at one atmospheric pressure, boiling point: 217.9℃, critical temperature: 475.2℃; The working fluid of the solar heat pipe adopts methanol, the chemical formula is CH ₃ OH, the melting point: -97.8°C, the boiling point: 64.7°C, and the critical temperature: 240°C under one atmospheric pressure; The structure of the solar heat pipe is, from the outside to the inside, the high light-transmitting resin sheath, the graphene solar energy absorption coating + the copper heat pipe, and the structure of the solar heat pipe heat exchanger is the high light-transmitting resin sheath from the outside to the inside. Cover, graphene solar absorption coating + copper heat exchanger, the naphthalene transported by the pipeline not only absorbs the heat released by the condensing section of the solar heat pipe in the solar heat pipe heat exchanger, but also absorbs the solar light absorbed by the shell of the solar heat pipe heat exchanger hot. 3 . The control method for a solar-assisted mid-deep geothermal heat pipe energy system according to claim 1 , wherein: a working medium tank phase change heat storage module is arranged inside the thermal working medium tank; 3 . The materials of the working fluid tank phase change heat storage module and the heating phase change heat storage module are all ternary molten salts, that is, mixed nitrates with a mass fraction of 53% potassium nitrate + 40% sodium nitrite + 7% sodium nitrate. , its melting point is 142 °C, and its vaporization point is 500 °C. 4 . The control method for a solar-assisted mid-deep geothermal heat pipe energy system according to claim 3 , wherein the part of the geothermal heat pipe in contact with the ground is provided with a pressure-resistant sealing protective layer and a ground hardening protective layer. 5 .

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