A multi-energy complementary integrated energy system and utilization method based on solar energy, geothermal energy, and wastewater waste heat

Abstract

This invention belongs to the field of energy utilization technology, and specifically relates to a multi-energy complementary integrated energy system and utilization method based on solar energy, geothermal energy, and wastewater waste heat. The system includes a wastewater trunk line, a wastewater treatment device, a wastewater source heat exchanger, photovoltaic thermal modules, an evaporator, a compressor, a condenser, a throttling device, a shallow geothermal well group, medium-deep geothermal wells, an ORC evaporator, an expander, an ORC generator, an ORC condenser, a heat storage tank, a trough collector, a water distributor, a water collector, and an isolated power grid. During the heating season, this invention uses medium-deep and shallow geothermal energy as the main heat sources, combined with wastewater waste heat and solar thermal energy, to provide heating and generate electricity for users through heat pump units and organic Rankine cycle waste heat recovery. During the non-heating season, wastewater waste heat, solar thermal energy, and waste heat from geothermal power generation are injected into the shallow geothermal well group for cross-seasonal heat storage, achieving multi-energy complementarity and cross-seasonal energy storage of geothermal, solar, and wastewater waste heat.

Description

Technical Field

[0001] This invention relates to the field of energy utilization technology, specifically to a multi-energy complementary integrated energy system and utilization method based on solar energy, geothermal energy, and wastewater waste heat. Background Technology

[0002] By recovering low-grade heat energy from urban sewage, traditional coal-fired and gas-fired boilers can be used for heating, significantly reducing carbon emissions. It is estimated that recovering waste heat from 1 ton of sewage (with a temperature difference of 5°C) can reduce the consumption of approximately 10 kg of standard coal, corresponding to a reduction of 25 kg of carbon dioxide emissions. The "Implementation Opinions on Promoting Synergistic Efficiency in Sewage Treatment for Pollution Reduction and Carbon Reduction" proposes to construct regional reclaimed water recycling projects in an orderly manner, taking into account local natural resources and social development needs. It also encourages the construction of reclaimed water plants along industrial parks and promotes the "winter storage and summer use" of reclaimed water in arid Northwest regions, tailored to local conditions.

[0003] Although geothermal energy, solar energy, and wastewater heat each have promising application prospects, existing technologies still have the following shortcomings: First, long-term extraction of heat from geothermal energy alone reduces the sustainability of the geothermal system, causing a drop in geothermal resource temperature or a prolonged heat recovery cycle. Meanwhile, solar energy resources are intermittent and fluctuating, making it difficult to use as a stable heat source or power source alone. Second, traditional geothermal power generation systems (such as Organic Rankine Cycle (ORC) systems) have high requirements for the stability of heat source temperature and flow rate. When the heat source temperature fluctuates or the flow rate is insufficient, power generation efficiency decreases or even shuts down, lacking an effective short-term heat storage compensation mechanism. Third, wastewater heat and solar thermal energy are mostly low-grade heat energy, often wasted during the non-heating season, lacking cross-seasonal energy storage methods to store them for use during the heating season. Shallow geothermal well clusters are usually only used for passive heat extraction, failing to achieve active heat storage and seasonal regulation. Fourth, park-level energy systems are mostly grid-connected. When the main grid fails or renewable energy fluctuates, the system's self-consistency is weak, making it difficult to achieve bidirectional coordinated control of electricity and heat and islanded operation.

[0004] Therefore, it is necessary to develop an integrated energy system that can combine solar energy, geothermal energy and waste heat from sewage, and has the capabilities of cross-seasonal heat storage, heat and power synergy and isolated grid regulation, in order to solve the problems of low utilization rate of renewable energy, poor energy supply stability, depletion of geothermal resources and waste of low-grade heat energy in existing technologies. Summary of the Invention

[0005] To address the aforementioned problems, the purpose of this invention is to provide a multi-energy complementary integrated energy system and utilization method based on solar energy, geothermal energy, and wastewater waste heat. This invention achieves integrated power generation, thermal energy storage, district heating, and cross-seasonal thermal storage functions. It organically integrates deep geothermal energy, shallow geothermal energy, primary or regenerated wastewater waste heat, solar photovoltaic and solar thermal energy, and multi-scale thermal storage technologies to construct a multi-energy complementary energy supply architecture covering underground cross-seasonal energy storage, efficient recovery of wastewater waste heat, sensible and latent heat storage, and solar thermal utilization. The overall energy utilization efficiency is significantly improved, the system operation is more intelligent, and the cost is reduced.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat, comprising a wastewater trunk line, medium-deep geothermal wells, an ORC power generation unit, a water distributor, a water collector, and a power grid. The wastewater trunk line is sequentially connected to a wastewater treatment device, a wastewater source heat exchanger, and a heat pump unit. The heat pump unit comprises an evaporator, a compressor, a condenser, and a throttling device connected in a closed loop. The inlet of the evaporator is connected to the outlet of the wastewater source heat exchanger, and the outlet of the evaporator is also connected to a photovoltaic thermal module. The inlet of the evaporator is also connected to a shallow geothermal well group. The ORC power generation unit comprises sequentially connected... The system includes an ORC evaporator, an expander, an ORC generator, and an ORC condenser. The outlet of the medium-deep geothermal well is connected to the first inlet of the Organic Rankine Cycle ORC evaporator. The second inlet of the ORC evaporator is connected to a heat storage tank, which is connected to a trough-type solar collector. The outlet of the condenser is connected to the water distributor via a valve, and the outlet of the ORC condenser is also connected to the water distributor via a valve. The water collector is connected to both the inlet of the condenser and the inlet of the ORC condenser. The water distributor and the water collector are connected to heat users. The power grid is electrically connected to the ORC generator, the photovoltaic thermal module, and the compressor.

[0007] A valve V4 is installed on the pipeline between the outlet of the wastewater source heat exchanger and the inlet of the evaporator; a valve V3 is installed on the pipeline between the inlet of the wastewater source heat exchanger and the outlet of the evaporator; a valve V1 is installed on the pipeline between the outlet of the shallow geothermal well group and the inlet of the evaporator; a valve V2 is installed on the pipeline between the inlet of the shallow geothermal well group and the outlet of the evaporator; a valve V7 is installed on the pipeline between the condenser and the water distributor; a valve V8 is installed on the pipeline between the ORC condenser and the water distributor; a valve V5 is installed on the pipeline between the water collector and the inlet of the condenser; and a valve V6 is installed on the pipeline between the water collector and the inlet of the ORC condenser.

[0008] A valve V10 is installed on the pipeline between the outlet of the thermal storage tank and the ORC condenser; a valve V16 is installed on the pipeline between the outlet of the shallow geothermal well group and the ORC condenser; and a valve V15 is installed on the pipeline between the inlet of the shallow geothermal well group and the ORC condenser.

[0009] A valve V11 is installed on the pipeline between the inlet of the ORC condenser and the inlet of the evaporator, a valve V12 is installed on the pipeline between the outlet of the ORC condenser and the evaporator, a valve V14 is installed at the inlet of the evaporator, and a valve V13 is installed at the outlet of the evaporator.

[0010] A multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat, using a multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat as described above, including a heating season operation mode and a non-heating season operation mode; The heating season operation mode includes at least one of the following conditions: Wastewater source heat pump heating mode: Water from the wastewater trunk line enters the evaporator of the heat pump unit through the wastewater treatment device and wastewater source heat exchanger. After being heated by the compressor, the water is then supplied to the heat users through the condenser and water distributor. Shallow geothermal heating operation: hot water from the shallow geothermal well group enters the evaporator of the heat pump unit, is heated by the compressor, and then supplied to the heat users through the condenser and water distributor. Coupled heating mode: hot water from medium-deep geothermal wells enters the ORC evaporator to drive the ORC power generation unit to generate electricity, and the waste heat from the ORC condenser is supplied to heat users through the water distributor. At the same time, the sewage source heat pump or shallow geothermal heating mode can be operated in parallel. The non-heating season operation mode includes: Photovoltaic thermal module supplementary heating mode: After the photovoltaic thermal module heats the waste heat of the sewage, the heat is injected into the shallow geothermal well group for cross-seasonal heat storage. Geothermal power generation waste heat supplementation operation: The waste heat of the ORC condenser is injected into the shallow geothermal well group for cross-seasonal heat supplementation.

[0011] In the sewage source heat pump heating operation, valves V3, V4, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The water from the sewage trunk line flows sequentially through the sewage treatment device, sewage source heat exchanger, evaporator, compressor, and condenser, and then through the water distributor and water collector to provide heating to the heat users.

[0012] In the shallow geothermal heating operation, valves V1, V2, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The hot water from the shallow geothermal well group enters the evaporator, is heated by the compressor, and then supplied to the heat users by the condenser through the distributor and collector.

[0013] In the coupled heating mode, hot water from the medium-deep geothermal well enters the ORC evaporator and flows sequentially through the expander, ORC generator, and ORC condenser. The waste heat from the ORC condenser is distributed to the heat users via the water distributor and collector. At the same time, the sewage source heat pump heating mode or the shallow geothermal heating mode operates in parallel.

[0014] During the heating season, when the solar resources meet the requirements, the parabolic trough collector collects solar heat and stores it in the heat storage tank; when the inlet heat source temperature or flow rate of the ORC evaporator is lower than the set value, the heat storage tank releases the stored heat to the second inlet of the ORC evaporator to supplement the heat of the ORC evaporator.

[0015] In the photovoltaic thermal module reheating mode, valves V3, V4, V1, and V2 are opened to inject the waste heat from the heated wastewater into the shallow geothermal well group; in the geothermal power generation waste heat reheating mode, valves V15, V16, V1, and V2 are opened to inject the waste heat from the ORC condenser into the shallow geothermal well group.

[0016] Compared with existing technologies, this invention has the following beneficial effects: 1. This invention utilizes the waste heat from the ORC condenser in geothermal power generation for heating. Simultaneously, a heat storage tank is installed on the ORC evaporator side. During periods of sufficient sunshine, the parabolic trough collector collects solar heat and stores it in the heat storage tank. When the geothermal fluid temperature fluctuates, the flow rate is insufficient, or the load demand suddenly increases, the heat storage tank can release the stored heat to supplement the working fluid at the evaporator inlet, thereby stabilizing the operating parameters of the ORC system and avoiding the risk of decreased power generation efficiency or shutdown due to unstable heat sources. 2. This invention synergistically introduces waste heat from wastewater and solar thermal resources into a shallow geothermal well cluster system. The waste heat from the geothermal power generation system can also be used to supplement the shallow geothermal well cluster. Cross-seasonal heat storage design is implemented to achieve efficient collection, seasonal storage, and on-demand release of low-grade heat energy. While improving the energy storage capacity and temperature quality of shallow geothermal systems, this invention optimizes the utilization efficiency of geothermal resources over time, promoting the transformation of geothermal energy from a "passive heat extraction" to an "active heat storage—high-value energy supply" model, effectively facilitating the high-value, refined, and sustainable application of geothermal resources. 3. This invention constructs a park-level isolated power grid system, achieving a high degree of autonomy and flexible control of the energy system. This isolated grid uses local renewable energy sources such as geothermal power generation and photovoltaic power generation as the main power source, combined with waste heat recovery, energy storage devices, and an energy management system, forming a microgrid architecture independent of the main power grid. Under the premise of ensuring power supply security and power quality, the power generation output is dynamically adjusted according to heat load demand, and through a heat-power synergy mechanism, precise matching and dynamic balance between power supply and heat demand across multiple time scales are achieved. 4. During the heating season, this invention uses medium-deep and shallow geothermal energy as the main heat source, collaboratively utilizing waste heat from geothermal power generation, waste heat from sewage, and solar thermal energy as auxiliary heat sources to jointly meet the dual needs of the park for electricity and heating. Relying on a high-precision automatic control system and a distributed temperature monitoring network, the system performs tiered collection and layered storage of multi-grade thermal energy. It also deeply integrates the energy consumption patterns of the industrial park with real-time changes in solar energy resources, achieving intelligent coordination and dynamic optimization between thermal storage scheduling and renewable energy heating. This significantly reduces the overall energy consumption and economic costs of the system while fully ensuring energy supply reliability and user comfort. 5. During the non-heating season, the system synergistically injects wastewater heat and solar thermal resources into a shallow geothermal well cluster. Through cross-seasonal thermal storage, it achieves efficient collection, seasonal storage, and on-demand release of low-grade thermal energy. Simultaneously, waste heat from the geothermal power generation system can also supplement the shallow geothermal well cluster, ensuring full utilization of geothermal resources throughout the year.

[0017] The following will provide further explanation in conjunction with the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat according to the present invention.

[0019] In the diagram: 1-Sewage trunk line; 2-Sewage treatment unit; 3-Sewage source heat exchanger; 4-Photovoltaic thermal module; 5-Evaporator; 6-Throttling device; 7-Compressor; 8-Condenser; 9-Heat storage tank; 10-ORC evaporator; 11-Expander; 12-ORC generator; 13-ORC condenser; 14-Medium-deep geothermal well; 15-Water distributor; 16-Water collector; 17-Trough collector; 18-Shallow geothermal well group; 19-Heat user; 20-Power grid; V1~V16: Valves V1~V16. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1 Reference Figure 1 As shown, a multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat includes a wastewater trunk line 1, a medium-deep geothermal well 14, an ORC power generation unit, a water distributor 15, a water collector 16, and a power grid 20. The wastewater trunk line 1 is sequentially connected to a wastewater treatment device 2, a wastewater source heat exchanger 3, and a heat pump unit. The heat pump unit includes an evaporator 5, a compressor 7, a condenser 8, and a throttling device 6 connected in a closed loop. The inlet of the evaporator 5 is connected to the outlet of the wastewater source heat exchanger 3, and the outlet of the evaporator 5 is also connected to a photovoltaic thermal module 4. The inlet of the evaporator 5 is also connected to a shallow geothermal well group 18. The ORC power generation unit includes an ORC evaporator 10, an expander 11, and an O2O2 generator connected in a closed loop. The RC generator 12 and ORC condenser 13 are connected. The outlet of the medium-deep geothermal well 14 is connected to the first inlet of the organic Rankine cycle ORC evaporator 10. The second inlet of the ORC evaporator 10 is connected to a heat storage tank 9, which is connected to a trough collector 17. The outlet of the condenser 8 is connected to the water distributor 15 via a valve. The outlet of the ORC condenser 13 is also connected to the water distributor 15 via a valve. The water collector 16 is connected to the inlet of the condenser 8 and the inlet of the ORC condenser 13, respectively. The water distributor 15 and the water collector 16 are connected to heat users 19, respectively. The power grid 20 is electrically connected to the ORC generator 12, the photovoltaic thermal module 4, and the compressor 7, respectively.

[0022] In use, during the heating season, the high-temperature hot water output from the medium-deep geothermal well 14 enters the ORC evaporator 10 to drive the expander 11 and ORC generator 12 to generate electricity, which is then fed into the power grid 20 for use in the park. The waste heat from the ORC condenser 13 is supplied to the heat users 19 via the distributor 15. Simultaneously, depending on the heat load demand, either the sewage source heat pump or the shallow geothermal heat pump mode can be selected: sewage from the sewage trunk 1 enters the evaporator 5 via the sewage treatment device 2 and the sewage source heat exchanger 3, or hot water from the shallow geothermal well group 18 enters the evaporator 5, is heated by the compressor 7, and then supplemented with heating by the condenser 8 through the distributor 15. During the non-heating season, the heating valves are closed, and the photovoltaic thermal modules 4 are turned on to heat the waste heat from the sewage, or the waste heat from the ORC condenser 13 is injected into the shallow geothermal well group 18 via valve control for cross-seasonal heat storage. This invention realizes the multi-energy complementary integration of medium-deep geothermal power generation, shallow geothermal heat pump, sewage source heat pump and solar thermal, and constructs a complete integrated energy system covering power generation, heating and cross-seasonal heat storage, providing a basic framework for subsequent valve control conditions.

[0023] Example 2 Based on Embodiment 1, in this embodiment, preferably, a valve V4 is provided on the pipeline between the outlet of the wastewater source heat exchanger 3 and the inlet of the evaporator 5; a valve V3 is provided on the pipeline between the inlet of the wastewater source heat exchanger 3 and the outlet of the evaporator 5; a valve V1 is provided on the pipeline between the outlet of the shallow geothermal well group 18 and the inlet of the evaporator 5; a valve V2 is provided on the pipeline between the inlet of the shallow geothermal well group 18 and the outlet of the evaporator 5; a valve V7 is provided on the pipeline between the condenser 8 and the water distributor 15; a valve V8 is provided on the pipeline between the ORC condenser 13 and the water distributor 15; a valve V5 is provided on the pipeline between the water collector 16 and the inlet of the condenser 8; and a valve V6 is provided on the pipeline between the water collector 16 and the inlet of the ORC condenser 13.

[0024] In use, this invention achieves switching between different heat sources and heating terminals by controlling the opening and closing of valves V1, V2, V3, V4, V5, V6, V7, and V8. When sewage source heat pump heating is required, valves V3, V4, V5, and V7 are opened, and valves V1, V2, V6, and V8 are closed, establishing sewage-side circulation. Heat from the condenser 8 is sent to the manifold 15 via V7. When shallow geothermal heat pump heating is required, valves V1, V2, V5, and V7 are opened, and valves V3, V4, V6, and V8 are closed, establishing shallow geothermal water circulation. When ORC waste heat direct heating is required, valves V6 and V8 are opened, and valves V5 and V7 are closed. Heat from the ORC condenser 13 is sent to the manifold 15 via V8. This invention enables flexible switching and independent control between three modes—sewage source heat pump, shallow ground source heat pump, and ORC waste heat heating—through valve groups, ensuring the system's adaptability and operational reliability under different heat source conditions and avoiding cross-current interference between different heat source circuits.

[0025] Example 3 Based on Embodiment 1, in this embodiment, preferably, a valve V10 is provided on the pipeline between the outlet of the heat storage tank 9 and the ORC condenser 13, a valve V16 is provided on the pipeline between the outlet of the shallow geothermal well group 18 and the ORC condenser 13, and a valve V15 is provided on the pipeline between the inlet of the shallow geothermal well group 18 and the ORC condenser 13.

[0026] In use, during the heating season when there is sufficient sunshine, the trough collector 17 is turned on to collect solar heat and store it in the heat storage tank 9. Valve V10 is opened, and the heat storage tank 9 provides supplemental heat to the second inlet of the ORC evaporator 10, maintaining a stable ORC evaporation temperature. When a drop in the outlet water temperature or insufficient flow is detected in the medium-deep geothermal well 14, V10 is automatically opened to release the stored heat. During the non-heating season, valves V15 and V16 are opened to introduce the waste heat from the ORC condenser 13 into the shallow geothermal well group 18 for supplemental heating; simultaneously, V15, V16, V1, and V2 can be opened to circulate the waste heat into the well group. This invention utilizes the heat storage tank to provide short-term supplemental heating to the ORC evaporator, smoothing geothermal source fluctuations and improving the stability of the power generation system; at the same time, it utilizes the waste heat from the ORC condenser and solar heat to perform cross-seasonal heat storage in the shallow geothermal well group, improving the temperature quality of the well group and realizing the time-based transfer of waste heat resources.

[0027] Example 4 Based on Embodiment 1, in this embodiment, preferably, a valve V11 is provided on the pipeline between the inlet of the ORC condenser 13 and the evaporator 5, a valve V12 is provided on the pipeline between the outlet of the ORC condenser 13 and the evaporator 5, a valve V14 is provided at the inlet of the evaporator 5, and a valve V13 is provided at the outlet of the evaporator 5.

[0028] When using this invention, during the heating season, when the wastewater source heat pump or shallow geothermal heat pump is running, valves V11 and V12 can be opened to introduce the waste heat from the ORC condenser 13 into the inlet of the evaporator 5 of the heat pump unit, increasing the inlet water temperature of the evaporator 5 and thus improving the heating efficiency of the heat pump. Specifically, valves V11 and V14 are opened to allow the ORC waste heat to mix with wastewater or shallow geothermal water before entering the evaporator 5; valves V12 and V13 are opened to establish a waste heat recovery bypass. This invention utilizes the waste heat from ORC power generation in a cascade manner to the heat pump evaporator side, increasing the evaporation temperature of the heat pump, thereby improving the heating performance coefficient of the heat pump, reducing compressor energy consumption, and achieving deep waste heat recovery and energy level matching.

[0029] Example 5 A multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat, using a multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat as described above, including a heating season operation mode and a non-heating season operation mode; The heating season operation mode includes at least one of the following conditions: Wastewater source heat pump heating mode: Water from the wastewater trunk 1 enters the evaporator 5 of the heat pump unit through the wastewater treatment device 2 and the wastewater source heat exchanger 3. After being heated by the compressor 7, it is supplied to the heat user 19 through the condenser 8 and the water distributor 15. Shallow geothermal heating mode: hot water from shallow geothermal well group 18 enters the evaporator 5 of heat pump unit, is heated by compressor 7, and then supplied to heat users 19 by condenser 8 through water distributor 15. Coupled heating mode: hot water from the medium-deep geothermal well 14 enters the ORC evaporator 10 to drive the ORC power generation unit to generate electricity, and the waste heat of the ORC condenser 13 is supplied to the heat user 19 through the water distributor 15. At the same time, the sewage source heat pump or shallow geothermal heating mode can be operated in parallel. The non-heating season operation mode includes: Photovoltaic thermal module supplementary heating mode: After the photovoltaic thermal module 4 heats the waste heat of the sewage, the heat is injected into the shallow geothermal well group 18 for cross-seasonal heat storage. Geothermal power generation waste heat supplementation operation: The waste heat of ORC condenser 13 is injected into shallow geothermal well group 18 for cross-seasonal heat supplementation.

[0030] In the sewage source heat pump heating operation, valves V3, V4, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The water from the sewage trunk 1 flows sequentially through the sewage treatment device 2, the sewage source heat exchanger 3, the evaporator 5, the compressor 7, and the condenser 8, and then through the water distributor 15 and the water collector 16 to provide heating for the heat users 19.

[0031] In the shallow geothermal heating operation, valves V1, V2, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The hot water from the shallow geothermal well group 18 enters the evaporator 5, is heated by the compressor 7, and then supplied to the heat users 19 by the condenser 8 through the water distributor 15 and the water collector 16.

[0032] In the coupled heating mode, the hot water from the medium-deep geothermal well 14 enters the ORC evaporator 10 and flows sequentially through the expander 11, the ORC generator 12 and the ORC condenser 13. The waste heat from the ORC condenser 13 is used to provide heating to the heat users 19 through the water distributor 15 and the water collector 16. At the same time, the sewage source heat pump heating mode or the shallow geothermal heating mode operates in parallel.

[0033] During the heating season, when the solar resources meet the requirements, the parabolic trough collector 17 collects solar heat and stores it in the heat storage tank 9. When the inlet heat source temperature or flow rate of the ORC evaporator 10 is lower than the set value, the heat storage tank 9 releases the stored heat to the second inlet of the ORC evaporator 10 to supplement the heat of the ORC evaporator 10.

[0034] In the photovoltaic thermal module reheating mode, valves V3, V4, V1, and V2 are opened to inject the waste heat from the heated wastewater of the photovoltaic thermal module 4 into the shallow geothermal well group 18; in the geothermal power generation waste heat reheating mode, valves V15, V16, V1, and V2 are opened to inject the waste heat from the ORC condenser 13 into the shallow geothermal well group 18.

[0035] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater heat, characterized in that: The system includes a sewage trunk line (1), a medium-deep geothermal well (14), an ORC power generation unit, a water distributor (15), a water collector (16), and a power grid (20). The sewage trunk line (1) is connected in sequence to a sewage treatment device (2), a sewage source heat exchanger (3), and a heat pump unit. The heat pump unit includes an evaporator (5), a compressor (7), a condenser (8), and a throttling device (6) connected in a closed loop. The inlet of the evaporator (5) is connected to the outlet of the sewage source heat exchanger (3), and the outlet of the evaporator (5) is also connected to a photovoltaic thermal module (4). The inlet of the evaporator (5) is also connected to a shallow geothermal well group (18). The ORC power generation unit includes an ORC evaporator (10), an expander (11), an ORC generator (12), and an ORC condenser (13) connected in sequence. 13), the outlet of the medium-deep geothermal well (14) is connected to the first inlet of the organic Rankine cycle (ORC) evaporator (10), the second inlet of the ORC evaporator (10) is connected to the heat storage tank (9), the heat storage tank (9) is connected to the trough collector (17); the outlet of the condenser (8) is connected to the water distributor (15) through a valve, the outlet of the ORC condenser (13) is connected to the water distributor (15) through a valve, the water collector (16) is connected to the inlet of the condenser (8) and the inlet of the ORC condenser (13) respectively; the water distributor (15) and the water collector (16) are connected to the heat user (19) respectively, and the power grid (20) is electrically connected to the ORC generator (12), the photovoltaic thermal module (4) and the compressor (7) respectively.

2. The multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater heat as described in claim 1, characterized in that: A valve V4 is provided on the pipeline between the outlet of the wastewater source heat exchanger (3) and the inlet of the evaporator (5); a valve V3 is provided on the pipeline between the inlet of the wastewater source heat exchanger (3) and the outlet of the evaporator (5); a valve V1 is provided on the pipeline between the outlet of the shallow geothermal well group (18) and the inlet of the evaporator (5); a valve V2 is provided on the pipeline between the inlet of the shallow geothermal well group (18) and the outlet of the evaporator (5); a valve V7 is provided on the pipeline between the condenser (8) and the water distributor (15); a valve V8 is provided on the pipeline between the ORC condenser (13) and the water distributor (15); a valve V5 is provided on the pipeline between the water collector (16) and the inlet of the condenser (8); and a valve V6 is provided on the pipeline between the water collector (16) and the inlet of the ORC condenser (13).

3. The multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater heat as described in claim 1, characterized in that: A valve V10 is provided on the pipeline between the outlet of the heat storage tank (9) and the ORC condenser (13), a valve V16 is provided on the pipeline between the outlet of the shallow geothermal well group (18) and the ORC condenser (13), and a valve V15 is provided on the pipeline between the inlet of the shallow geothermal well group (18) and the ORC condenser (13).

4. The multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater heat as described in claim 1, characterized in that: A valve V11 is provided on the pipeline between the inlet of the ORC condenser (13) and the inlet of the evaporator (5), a valve V12 is provided on the pipeline between the outlet of the ORC condenser (13) and the outlet of the evaporator (5), a valve V14 is provided at the inlet of the evaporator (5), and a valve V13 is provided at the outlet of the evaporator (5).

5. A multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat, using the multi-energy complementary integrated energy system based on solar energy, geothermal energy, and wastewater waste heat as described in claim 1, characterized in that, This includes operating modes during the heating season and non-heating season; The heating season operation mode includes at least one of the following conditions: Wastewater source heat pump heating operation: Water from the wastewater trunk line (1) enters the evaporator (5) of the heat pump unit through the wastewater treatment device (2) and the wastewater source heat exchanger (3). After being heated by the compressor (7), the water is supplied to the heat users (19) through the condenser (8) and the water distributor (15). Shallow geothermal heating operation: hot water from the shallow geothermal well group (18) enters the evaporator (5) of the heat pump unit, is heated by the compressor (7), and then supplied to the heat user (19) by the condenser (8) through the water distributor (15); Coupled heating mode: hot water from the medium-deep geothermal well (14) enters the ORC evaporator (10) to drive the ORC power generation unit to generate electricity, and the waste heat of the ORC condenser (13) is supplied to the heat user (19) through the water distributor (15). At the same time, the sewage source heat pump or shallow geothermal heating mode is operated in parallel. The non-heating season operation mode includes: Photovoltaic thermal module supplementary heating condition: After the photovoltaic thermal module (4) heats the waste heat of the sewage, the heat is injected into the shallow geothermal well group (18) for cross-seasonal heat storage; Geothermal power generation waste heat supplementation operation: The waste heat of ORC condenser (13) is injected into shallow geothermal well group (18) for cross-seasonal heat supplementation.

6. The multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat as described in claim 5, characterized in that: In the sewage source heat pump heating operation, valves V3, V4, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The water in the sewage trunk line (1) flows through the sewage treatment device (2), sewage source heat exchanger (3), evaporator (5), compressor (7), and condenser (8) in sequence, and then through the water distributor (15) and water collector (16) to provide heating for the heat users (19).

7. The multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat as described in claim 5, characterized in that: In the shallow geothermal heating operation, valves V1, V2, V5, V7, V13, and V14 are opened, and the remaining valves are closed. The hot water from the shallow geothermal well group (18) enters the evaporator (5), is heated by the compressor (7), and then supplied to the heat users (19) by the condenser (8) through the water distributor (15) and the water collector (16).

8. The multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat as described in claim 5, characterized in that: In the coupled heating mode, the hot water from the medium-deep geothermal well (14) enters the ORC evaporator (10) and flows sequentially through the expander (11), ORC generator (12) and ORC condenser (13). The waste heat from the ORC condenser (13) is used to heat users (19) through the water distributor (15) and water collector (16). At the same time, the sewage source heat pump heating mode or the shallow geothermal heating mode operates in parallel.

9. The multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat as described in claim 5, characterized in that: During the heating season, when the solar resources meet the requirements, the trough collector (17) collects solar heat and stores it in the heat storage tank (9); when the inlet heat source temperature or flow rate of the ORC evaporator (10) is lower than the set value, the heat storage tank (9) releases the stored heat to the second inlet of the ORC evaporator (10) to supplement the heat of the ORC evaporator (10).

10. The multi-energy complementary integrated energy utilization method based on solar energy, geothermal energy, and wastewater waste heat according to claim 5, characterized in that: In the photovoltaic thermal module reheating operation, valves V3, V4, V1, and V2 are opened to inject the waste heat from the heated wastewater of the photovoltaic thermal module (4) into the shallow geothermal well group (18); in the geothermal power generation waste heat reheating operation, valves V15, V16, V1, and V2 are opened to inject the waste heat from the ORC condenser (13) into the shallow geothermal well group (18).

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