A zero-carbon energy supply system for a shallow and medium-deep geothermal energy coupled photovoltaic and energy storage system

Abstract

A zero-carbon energy supply system for a coupled shallow geothermal and medium-deep geothermal photovoltaic energy storage system, comprising a geothermal energy module, a photovoltaic energy storage system, an auxiliary cooling system, a water source heat pump unit, a large temperature difference heat pump unit, and an energy consumption unit. The geothermal energy module includes a shallow geothermal heat extraction (release) system, a medium-deep geothermal heat extraction system, a heat source circulation water pump, and a cold and heat source circulation pump; the photovoltaic energy storage system includes photovoltaic modules, an energy storage unit, and an inverter; the power distribution cabinet is connected to three power sources: the power grid, energy storage, and photovoltaic. This invention patent can effectively solve the problems of excessive consumption of standard coal and high carbon emissions caused by building air-conditioning loads, make full use of renewable energy, and achieve zero-carbon buildings by reasonably configuring the photovoltaic, energy storage, and geothermal systems.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive application of renewable energy, and particularly relates to a zero-carbon energy supply system for a shallow and medium-deep geothermal energy coupled with a photovoltaic energy storage system. Background Art

[0002] The ground source heat pump technology uses the circulating water in the underground closed pipeline as a heat source, which enters the evaporator of the heat pump unit. After the energy is lifted through the refrigeration / heat working medium cycle inside the heat pump unit, this part of the heat is released to the heating working medium through the condenser to achieve stable heating; in summer, the shallow ground source heat pump system can realize cooling through the conversion of the four-way valve inside the heat pump unit and release the heat to the ground to ensure the balance of the underground temperature field.

[0003] Photovoltaic power generation is a technology that directly converts light energy into electrical energy by using the photovoltaic effect at the semiconductor interface. It mainly consists of three major parts: solar panels (modules), controllers, and inverters, and the main components are composed of electronic components. The solar cells are connected in series and then encapsulated and protected to form a large-area solar cell module, and then combined with components such as a power controller to form a photovoltaic power generation device.

[0004] Energy storage: The energy storage in this application specifically refers to electrochemical energy storage, which is the process of energy storage, release, and management completed by batteries.

[0005] CN202210126403.5 discloses a geothermal - photovoltaic - energy storage multi - energy complementary energy station system, including a geothermal well module and an energy storage power generation module. The energy storage power generation module includes a photovoltaic panel, a power grid, and a battery system; the photovoltaic panel includes a bottom plate and a solar panel arranged above the bottom plate, and auxiliary rods and transmission rods parallel to each other are respectively arranged on the upper and lower sides of the solar panel. The patent only introduces a centralized energy supply system or a simple combination of renewable energies, and the specific utilization forms are not perfect. For example, for geothermal energy utilization, the way of directly using geothermal energy after heat exchange in this project is only suitable for individual abnormal areas with particularly good geothermal conditions, and is not applicable in most places.

[0006] CN202011052526.6 provides a method and system for combined operation of geothermal - photovoltaic - heat storage. The method includes: based on the combined combination method between a geothermal power station, a photovoltaic power station, and a heat storage power station, constructing a combined operation framework for the geothermal - photovoltaic - heat storage power station based on static cooperative game; through the combined operation framework, obtaining the optimal combined power generation mode of the geothermal power station, the photovoltaic power station, and the heat storage power station. The present invention is mainly based on geothermal power generation projects and is also a solution that can only be realized for specific regions, with a small scope of adaptation.

[0007] CN 113819510 A on December 21, 2021 provides a zero-emission heating system that couples medium and deep geothermal energy with solar energy. It includes an energy production unit, an energy storage unit, and an energy consumption unit. The energy production unit has a medium and deep buried pipe heat exchange device, a solar thermal collector device, and a photovoltaic power generation system. The energy storage unit has an electric heat storage boiler. The medium and deep buried pipe heat exchange device is connected to the electric heat storage boiler and / or the energy consumption unit through a medium and deep geothermal heat pump. The solar thermal collector device is connected to the electric heat storage boiler and / or the energy consumption unit. The photovoltaic power generation system is connected to an electricity storage device, and the electricity storage device is connected to the electric heat storage boiler, the medium and deep geothermal heat pump, and the energy consumption unit. The advantages are as follows: It realizes a composite and efficient heating and heat storage system. At the same time, through ultra-low energy consumption central heating and obtaining renewable clean electricity, zero emissions of the entire northern central heating system are achieved. In addition to heating, this patent also includes cooling, and it is applicable to both the north and the south. Current technologies cannot achieve zero-carbon energy use, cannot reduce the peak power load, do not improve the regulation ability of the energy system and the consumption ability of renewable energy, and energy-consuming units still face the contradiction between energy and electricity supply and demand. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects existing in the prior art and provide an air-conditioning system that can utilize shallow and medium and deep geothermal energy, and at the same time couple a photovoltaic and energy storage system to form a zero-carbon heating and cooling system. The purpose is to provide a heating and cooling system jointly composed of a buried pipe closed-loop heat pump system, a photovoltaic power generation system, an electrochemical energy storage system, etc., to meet the heating and cooling load requirements of buildings in winter and summer, and to achieve zero-carbon carbon emissions in buildings through a high-efficiency heating and cooling system and a renewable energy utilization system.

[0009] The technical solution adopted by the present invention to solve its technical problems is: A zero-carbon heating and cooling system formed by coupling a shallow and medium and deep geothermal energy combined air-conditioning system with a photovoltaic and energy storage system, including a geothermal heat extraction (release) system, a photovoltaic energy storage system, a water source heat pump unit, a large temperature difference water source heat pump unit, an energy consumption module, a power distribution cabinet, a power grid, an auxiliary cooling system, a valve assembly, and a microgrid control module;

[0010] The geothermal heat extraction and release system includes a shallow buried pipe heat exchanger, a medium and deep ground pipe heat exchanger, a first geothermal circulation water pump, and a second geothermal circulation water pump; the photovoltaic energy storage system includes a photovoltaic module, an energy storage unit, and an inverter connected in sequence, and the inverter is connected to the power distribution cabinet;

[0011] The water source heat pump unit includes a first evaporator, a first condenser, a first compressor, and a first expansion valve; the large temperature difference water source heat pump unit includes a second evaporator, a second condenser, a second compressor, and a second expansion valve;

[0012] The energy consumption unit includes a first cold and hot water circulation water pump, a second cold and hot water circulation water pump, and a fan coil unit;

[0013] The auxiliary cooling system includes a cooling tower and a cooling water circulation pump, and the auxiliary cooling system is connected to the condenser and the condenser; the power grid is connected to the power distribution cabinet; the power distribution cabinet is respectively connected to the heat extraction and release system, the water source heat pump unit, the large temperature difference water source heat pump unit, the energy consumption module, and the power supply interface of the auxiliary cooling system through the first power distribution circuit, the second circuit, the third power distribution circuit, the fourth power distribution circuit, and the fifth power distribution circuit.

[0014] Furthermore, the water source heat pump unit and the large temperature difference water source heat pump unit adopt environmentally friendly refrigerants.

[0015] Furthermore, the shallow buried tube heat exchanger in the geothermal heat extraction and release system has the functions of heat extraction and heat release. It extracts heat from the ground during the heating season and releases heat to the ground during the cooling season.

[0016] Furthermore, the medium and deep buried tube heat exchanger in the geothermal heat extraction and release system only operates during the heating season and extracts heat from the ground.

[0017] Furthermore, the photovoltaic energy storage system is directly connected to the power grid and the power distribution cabinet through an inverter, and can realize power supply from photovoltaic to the power distribution cabinet, charging of the energy storage module by photovoltaic, power transmission from photovoltaic to the power grid, power supply from the energy storage module to the power distribution cabinet, power supply from the power grid to the power distribution cabinet, and charging of the energy storage module by the power grid.

[0018] Furthermore, the power distribution cabinet supplies power to each module through different power distribution loops.

[0019] Furthermore, the shallow buried tube heat exchanger is equipped with a first geothermal circulation pump, which is connected to both the first evaporator and the first condenser of the water source heat pump unit through pipelines. The connection between the shallow buried tube heat exchanger and the first evaporator and the first condenser is realized by switching the first valve group and the third valve group on the branch pipeline.

[0020] Furthermore, the medium and deep buried tube heat exchanger is equipped with a second geothermal circulation pump, and the medium and deep buried tube heat exchanger is connected to the second evaporator of the large temperature difference water source heat pump unit through a water pipe.

[0021] The present invention combines geothermal energy and an auxiliary cooling system, and combines photovoltaic energy storage and the large power grid, making full use of renewable energy to achieve safe, efficient heating and cooling throughout the year and zero-carbon emission operation of the system;

[0022] By calculating the annual load of the energy consumption module, reasonably configuring the photovoltaic energy storage capacity, and through the conversion of the operation modes of the photovoltaic energy storage and the power grid in different seasons and different time periods, realizing the charging of the energy storage by photovoltaic, power transmission from photovoltaic to the power grid, and charging of the energy storage by the power grid during the low electricity price period, the entire system operates with zero carbon and low cost. Description of the Drawings

[0023] Figure 1It is a schematic diagram of the system principle of the embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the conversion principle of the cooling and heating conditions of the water source heat pump system in the embodiment of the present invention;

[0025] Figure 3 It is a schematic diagram of the conversion principle of the cooling and heating conditions of the large temperature difference water source heat pump system in the embodiment of the present invention;

[0026] Figure 4 It is a diagram of the photovoltaic energy storage and power grid power supply in the embodiment of the present invention;

[0027] Figure 5 It is a schematic diagram of the power distribution in the embodiment of the present invention. Specific implementation manners

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] As Figures 1-5 shown, this embodiment includes a geothermal heat extraction and release system 1, a photovoltaic energy storage system 2, a water source heat pump unit 3, a large temperature difference water source heat pump unit 4, an energy consumption module 5, a power distribution cabinet 6, a power grid 7, an auxiliary cooling system 8, a valve assembly 9, and a microgrid control module 10.

[0030] The geothermal heat extraction and release system 1 includes a shallow buried tube heat exchanger 101, a medium-deep ground tube heat exchanger 102, a first geothermal circulation pump 103, and a second geothermal circulation pump 104; the photovoltaic energy storage system 2 includes a photovoltaic module 201, an energy storage unit 202, and an inverter 203 connected in sequence, and the inverter 203 is connected to the power distribution cabinet 6.

[0031] The water source heat pump unit 3 includes a first evaporator 301, a first condenser 302, a first compressor 303, and a first expansion valve 304; the large temperature difference water source heat pump unit 4 includes a second evaporator 401, a second condenser 402, a second compressor 403, and a second expansion valve 404.

[0032] The energy consumption module 5 includes a first cold and hot water circulation pump 501, a second cold and hot water circulation pump 502, and a fan coil unit 505.

[0033] The auxiliary cooling system 8 includes a cooling tower 801 and a cooling water circulation pump 802. The auxiliary cooling system is connected to the condensers 302 and 402 in the water source heat pump unit and the large temperature difference water source heat pump unit; the power grid 7 is connected to the power distribution cabinet 6 and is connected to the photovoltaic module 201 and the energy storage unit 202 through the inverter 203; the power distribution cabinet 6 is respectively connected to the heat extraction and release system 1, the water source heat pump unit 3, the large temperature difference water source heat pump unit 4, the energy consumption module 5, and the power supply interface of the auxiliary cooling system 8 through the first power distribution circuit 601, the second power distribution circuit 602, the third power distribution circuit 603, the fourth power distribution circuit 604, and the fifth power distribution circuit 605.

[0034] The heat pump units (water source heat pump unit and large temperature difference water source heat pump unit) use environmentally friendly refrigerants. When the heat pump units operate: the refrigerants respectively pass through the compressors 303 / 403 and reach the condensers 302 / 402. The condensers 302 / 402 are switched through the valve groups on the pipelines. In winter, they are connected to the user unit 5, and in summer, they are connected to the cooling tower 8 and the shallow ground tube heat exchanger 101. Then, after passing through the throttle valves 304 / 404, they enter the evaporators 301 / 401. The evaporators 301 / 401 are switched through the valve groups on the pipelines. In winter, they are connected to the shallow buried tube heat exchanger 101 and the medium and deep buried tube heat exchanger 102, and in summer, they are connected to the user unit 5.

[0035] Heating condition: The water source heat pump unit and the large temperature difference water source heat pump unit operate. The third valve groups 109, the seventh valve groups 901, and the eighth valve groups 902 on the first bypass 905, the second bypass 906, and the third bypass 907 are closed. The auxiliary cooling module 8 and its corresponding cooling tower 801 and cooling water pump 803 are shut down. The sixth valve group 802 is closed. All other pipeline equipment and valves are in the open state. The geothermal circulating water flowing through the evaporators 301 / 401 extracts heat from the ground through the shallow buried tube heat exchanger 101 and the medium and deep buried tube heat exchanger 102 in the geothermal heat extraction and release system 1. The geothermal circulating water reaches the evaporators 301 / 401 through the first geothermal circulating water pump 103 and the second geothermal circulating water pump 104 to realize the heat source side circulation. The first heat metering device 107 measures the heat extracted and released from the shallow buried tube heat exchanger 101 to balance the underground temperature field. The second heat metering device 108 measures the heat extracted from the medium and deep buried tube heat exchanger 102 for the stability study of the medium and deep geothermal energy.

[0036] Cooling condition:

[0037] Cooling condition 1: The water source heat pump unit 3 and the shallow buried tube heat exchanger 101 in the geothermal heat extraction and release system 1 operate jointly. The large temperature difference heat pump unit 4 and the auxiliary cooling module 8 are shut down.

[0038] Close the equipment and valves on the pipelines connected to the large temperature difference water source heat pump unit 4, including the second valve group 106, the eighth valve group 902, the ninth valve group 903, the fifth valve group 504, the second geothermal circulation water pump 104, and the second cold and heat circulation water pump 502. Close the sixth valve group 802 on the pipeline connected to the auxiliary cooling module 8.

[0039] Operate the water source heat pump unit 3. The first bypass 905 and the second bypass 906 are opened, and the corresponding third valve group 109 and the seventh valve group 901 are opened. Close the first valve group 105 and the tenth valve group 904. The circulating water in the shallow geothermal heat exchanger flows through the first geothermal circulation water pump 103 through the first bypass 905 to the condenser 302 of the water source heat pump unit 3. The heat in the condenser 302 is carried by the circulating water (cooling water) flowing through the first bypass to the shallow buried tube heat exchanger 101 and released into the ground. The circulating water (cold water) in the energy consumption module 5 is transported to the air conditioning terminal 505 through the first cold and hot circulation water pump 501, and through the second bypass 906 to the evaporator 301. The refrigerant in the evaporator 301 absorbs the heat of the flowing circulating water to achieve the refrigeration cycle.

[0040] Cooling mode 2: The water source heat pump unit 3 and the auxiliary cooling module 8 operate jointly, and the large temperature difference heat pump unit 4 stops.

[0041] Close the equipment and valve groups on the pipelines connected to the large temperature difference heat pump unit 4, including the second valve group 106, the eighth valve group 902, the ninth valve group 903, the fifth valve group 504, the second geothermal circulation water pump 104, and the second cold and heat circulation water pump 502; close the equipment and valve groups on the pipeline of the shallow buried tube heat exchanger 101 in the geothermal heat extraction and release system 1, including the first geothermal circulation water pump 103, the first valve group 105, and the third valve group 109.

[0042] Operate the water source heat pump unit 3 and the auxiliary cooling module 8. The cooling tower 801 and the cooling water circulation pump 803 in the auxiliary cooling module 8 operate, and the sixth valve group 802 is opened. Close the tenth valve group 904. The cooling water in the auxiliary cooling module flows through the cooling water circulation pump 802 to the condenser 302 of the water source heat pump unit 3. The heat in the condenser 302 is carried by the cooling water to the cooling tower 801 and released into the atmosphere. The circulating water (cold water) in the energy consumption module 5 is transported to the air conditioning terminal 505 through the first cold and hot circulation water pump 501, and through the second bypass 906 to the evaporator 301. The refrigerant in the evaporator 301 absorbs the heat of the flowing circulating water to achieve the refrigeration cycle.

[0043] Cooling mode 3: The water source heat pump unit 3, the large temperature difference heat pump unit 4, and the auxiliary cooling module 8 operate jointly.

[0044] If the geothermal heat extraction and release system is not operating, close the first geothermal circulation pump 103, the second geothermal circulation pump 104, the first valve group 105, and the second valve group 106 in the geothermal heat extraction and release system, and close the ninth valve group 903 and the tenth valve group 904.

[0045] Operate the water source heat pump unit 3, the large temperature difference heat pump unit 4, and the auxiliary cooling module 8. The cooling tower 801 and the cooling water circulation pump 803 in the auxiliary cooling module 8 are operating, and the sixth valve group 802 is opened; the cooling water in the auxiliary cooling module passes through the cooling water circulation pump 802 to the condensers 302 of the water source heat pump unit 3 and the condensers 402 of the large temperature difference heat pump unit 4. The heat in the condensers 302 and 402 is carried by the cooling water to the cooling tower 801 and released into the atmosphere. The circulating water (cold water) in the energy consumption module 5 is transported to the air-conditioning terminal 505 through the first cold and hot water circulation pump 501 and the second cold and hot water circulation pump 502, passes through the second bypass 906 to the evaporator 301, and passes through the third bypass 907 to the evaporator 401. The refrigerant in the evaporators 301 and 401 absorbs the heat of the flowing circulating water to achieve the refrigeration cycle and jointly provide cooling capacity for the energy consumption module 5.

[0046] In this embodiment, all electrical equipment is connected to the distribution cabinet 6. The distribution cabinet 6 is connected to the photovoltaic energy storage system 2 and the power grid 7. The microgrid control platform 10 controls the photovoltaic module 201 and the energy storage unit 202 to realize function switching such as power supply, energy storage, and power transmission.

[0047] Mode 1: Direct photovoltaic power supply + energy storage

[0048] During the low energy consumption period, the power generation of the photovoltaic module 201 has a surplus. The photovoltaic module 201 preferentially supplies power to the distribution cabinet 6 through the inverter 203, and the excess power is transmitted to the energy storage module 202.

[0049] Mode 2: Combined power supply of photovoltaic power generation + energy storage

[0050] During the peak load period of energy consumption, the real-time power generation of the photovoltaic module 201 does not meet the power consumption load. At this time, the photovoltaic module 201 and the energy storage module 202 jointly supply power to the distribution cabinet 6.

[0051] Mode 3: Energy storage power supply

[0052] During the period when the light intensity is insufficient or there is no light, the energy storage module 202 supplies power to the distribution cabinet 6 alone to meet the load of the energy consumption system.

[0053] Module 4: Combined power supply of the power grid + energy storage

[0054] In this system, the power grid mainly serves as a backup power source. When there is no sunlight for a long time due to weather reasons, the power grid 7 and the energy storage module 202 jointly ensure the economic power supply of the distribution cabinet 6, and the charging and discharging periods can be adjusted according to the local peak-valley electricity price. Multiple modes such as power grid power supply, power grid charging, and energy storage power supply are realized.

[0055] The cooling water quality of this project meets the requirements of the cooling water quality specification for the air conditioning specialty.

[0056] Those skilled in the art can make various modifications and variations to the present invention. If these modifications and variations are within the scope of the claims of the present invention and its equivalent technologies, then these modifications and variations are also within the protection scope of the present invention.

[0057] The content not described in detail in the specification is the prior art well known to those skilled in the art.

Claims

1. A zero-carbon energy supply system for a shallow and medium-deep geothermal energy coupled photovoltaic and energy storage system, characterized in that: It includes a geothermal heat extraction and release system (1), a photovoltaic energy storage system (2), a water source heat pump unit (3), a large temperature difference water source heat pump unit (4), an energy consumption module (5), a power distribution cabinet (6), a power grid (7), an auxiliary cooling system (8), a valve assembly (9), and a microgrid control module (10); The geothermal heat extraction and release system (1) includes a shallow buried tube heat exchanger (101), a medium-deep ground tube heat exchanger (102), a first geothermal circulation water pump (103), and a second geothermal circulation water pump (104); the photovoltaic energy storage system (2) includes a photovoltaic module (201), an energy storage unit (202), and an inverter (203) connected in sequence, and the inverter (203) is connected to the power distribution cabinet (6); The water source heat pump unit (3) includes a first evaporator (301), a first condenser (302), a first compressor (303), and a first expansion valve (304); the large temperature difference water source heat pump unit (4) includes a second evaporator (401), a second condenser (402), a second compressor (403), and a second expansion valve (404); The energy consumption module (5) includes a first cold and hot water circulation water pump (501), a second cold and hot water circulation water pump (502), and a fan coil unit (505); The auxiliary cooling system (8) includes a cooling tower (801) and a cooling water circulation water pump (802), and the auxiliary cooling system (8) is connected to the first condenser (302) and the second condenser (402); the power grid (7) is connected to the power distribution cabinet (6); the power distribution cabinet (6) is respectively connected to the power supply interfaces of the geothermal heat extraction and release system (1), the water source heat pump unit (3), the large temperature difference water source heat pump unit (4), the energy consumption module (5), and the auxiliary cooling system (8) through a first power distribution circuit (601), a second power distribution circuit (602), a third power distribution circuit (603), a fourth power distribution circuit (604), and a fifth power distribution circuit (605); The shallow buried tube heat exchanger (101) is equipped with a first geothermal circulation water pump (103), and is connected to both the first evaporator (301) and the first condenser (302) of the water source heat pump unit (3) through pipelines. The connection between the shallow buried tube heat exchanger (101) and the first evaporator (301) and the first condenser (302) is realized by switching the first valve group (105) and the third valve group (109) on the branch pipeline; The medium-deep buried tube heat exchanger (102) is equipped with a second geothermal circulation water pump (104), and the medium-deep buried tube heat exchanger (102) is connected to the second evaporator (401) of the large temperature difference water source heat pump unit (4) through a water pipe.

2. The zero-carbon energy supply system of the shallow and medium-deep geothermal energy coupled with photovoltaic and energy storage system according to claim 1, characterized in that: The water source heat pump unit (3) and the large temperature difference water source heat pump unit (4) use environmentally friendly refrigerants.

3. The zero-carbon energy supply system of the shallow and medium-deep geothermal energy coupled with photovoltaic and energy storage system according to claim 2, characterized in that: The shallow buried tube heat exchanger (101) in the geothermal heat extraction and release system (1) has the functions of heat extraction and heat release, extracting heat from the ground in the heating season and releasing heat to the ground in the cooling season.

4. The zero-carbon energy supply system of the shallow and medium-deep geothermal energy coupled photovoltaic and energy storage system according to any one of claims 1-3, characterized in that: The medium-deep buried tube heat exchanger (102) in the geothermal heat extraction and release system (1) only operates in the heating season and extracts heat from the ground.

5. The zero-carbon energy supply system of the shallow and medium-deep geothermal energy coupled with photovoltaic energy storage system according to any one of claims 1-3, characterized in that: The photovoltaic energy storage system (2) is directly connected to the power grid (7) and the power distribution cabinet (6) through an inverter (203), and can realize power supply from the photovoltaic to the power distribution cabinet (6), charging of the energy storage module by the photovoltaic, power transmission from the photovoltaic to the power grid, power supply from the energy storage module to the power distribution cabinet, power supply from the power grid to the power distribution cabinet, and charging of the energy storage module by the power grid.

6. The zero-carbon energy supply system of the shallow and medium-deep geothermal energy coupled photovoltaic and energy storage system according to any one of claims 1-3, characterized in that: The power distribution cabinet (6) supplies power to each module through different power distribution loops.

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