Underground gravity energy storage combined with heat pump integrated energy system

Abstract

This invention discloses an integrated energy system combining underground gravity energy storage and a heat pump. The upper track is installed on the ground, with its straight section extending to the shaft opening. The lower track is installed inside the tunnel, with the same structure as the upper track, and its straight section extends to the bottom of the shaft. A support beam is installed at the shaft opening, with the support beams movably connected to each other. An electric generator and a winch are installed on the support beam. The heat pump heating (cooling) unit is located beside the ground track, with the heat exchange coil inside the heavy-duty carrier. One end is connected to the first port of a four-way valve, and the other end is sequentially connected to a throttling valve, the first side of the condenser / evaporator, and the third port of the four-way valve. The compressor inlet and outlet are connected to the second and fourth ports of the four-way valve, respectively. The second side of the condenser / evaporator is connected to the cooling / heating user. This invention can improve the penetration rate of renewable energy, achieve energy conservation and emission reduction, reduce system construction costs, occupy a small area, and allows for flexible site selection.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to an integrated energy system combining underground gravity energy storage with a heat pump. Background Technology

[0002] Energy structure adjustment, as a major path to achieving the "dual carbon" goals, is an important task facing energy development and a crucial component of ensuring energy security. Adjusting the energy structure means reducing the demand for and consumption of fossil fuel resources, decreasing dependence on oil, reducing the proportion of coal-fired power, and vigorously developing new and renewable energy sources.

[0003] There is a significant spatiotemporal mismatch between the distribution of renewable energy and electricity load. Furthermore, renewable energy sources such as wind and solar power are typically intermittent and random, meaning that a large proportion of them are directly connected to the grid can severely impact grid stability. This results in low utilization rates of renewable energy and severe curtailment of wind and solar power. High-capacity, high-efficiency, and low-cost power storage technologies are crucial for achieving large-scale grid integration of renewable energy and realizing green and sustainable development in the energy sector.

[0004] Gravity energy storage is an old and relatively mature energy storage technology, especially pumped-storage technology, which has achieved commercial operation. However, pumped-storage has high site selection requirements, necessitating the construction of upstream and downstream reservoirs, and its high evaporation rate makes site selection difficult in arid and water-scarce regions. Gravity potential energy storage systems that utilize inclined tracks and vertical shafts to lift heavy objects have attracted widespread attention and offer advantages for application in arid and water-scarce areas.

[0005] Existing underground gravity energy storage systems suffer from underutilization of underground low-temperature heat sources (i.e., geothermal resources). The temperature of the soil and rock mass below the surface and the groundwater is largely unaffected by changes in surface atmospheric temperature; its diurnal and seasonal temperature variations are minimal, making it a vast "constant temperature box," ideally suited as a heat source for winter heating and a cold source for summer cooling. However, traditional ground source heat pumps are costly to invest in, difficult to construct, and inconvenient to maintain. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned shortcomings and provide an integrated energy system that combines underground gravity energy storage with heat pumps, which reduces fossil energy consumption and carbon emissions, increases the penetration rate of renewable energy, reduces resource waste, achieves energy conservation and emission reduction, reduces system construction costs, occupies a small area, and allows for flexible site selection.

[0007] The technical solution of this invention is:

[0008] This invention discloses an integrated energy system combining underground gravity energy storage and a heat pump, comprising an underground gravity energy storage unit and a heat pump heating (cooling) unit. The underground gravity energy storage unit includes a shaft, a tunnel, an upper track, a lower track, a support beam frame, a support beam, an electric generator, a winch, and a load carrier. The upper track is installed on the ground and is circular with a straight section that shares a common straight section extending to the shaft opening. The lower track is installed inside the tunnel and is also circular with a straight section that shares a common straight section extending to the bottom of the shaft. The support beam frame is installed within the shaft. The support beam is movably connected to the support beam frame and located above the shaft opening; the electric generator and winch are installed on the support beam; the height of the support beam frame and the support beam is higher than the height of the heavy load carrier; the heat pump heating (cooling) unit is located next to the ground track and includes a compressor, condenser / evaporator, and heat exchange coil. The heat exchange coil is located inside the heavy load carrier, with one end connected to the first port of the four-way valve, and the other end connected to the throttle valve, the first side of the condenser / evaporator, and the third port of the four-way valve in sequence. The compressor inlet and outlet are connected to the second and fourth ports of the four-way valve, respectively, and the second side of the condenser / evaporator is connected to the cooling / heating user.

[0009] The aforementioned integrated energy system combining underground gravity energy storage and heat pumps includes a heavy-duty carrier filled with water and equipped with a temperature sensor.

[0010] The aforementioned integrated energy system combining underground gravity energy storage and heat pumps includes a suspension device for the heavy load carrier.

[0011] The aforementioned integrated energy system combining underground gravity energy storage and heat pumps includes multiple heavy-load carriers.

[0012] Compared with existing technologies, this invention has significant advantages. As can be seen from the above technical solution: when the heavy-load carrier in this invention is hoisted to the ground, it possesses not only gravitational potential energy but also low-temperature thermal energy. The heat pump heating (cooling) unit uses the water in the heavy-load carrier as a heat (cold) source, converting low-grade thermal (cold) energy into high-grade thermal (cold) energy through refrigerant circulation for user heating (cooling). This process is clean and pollution-free, effectively reducing user heating (cooling) costs and decreasing corresponding fossil fuel consumption and carbon emissions. This invention moves the "ground source" of traditional ground-source heat pumps to the ground, solving the problems of high investment costs, difficult construction, and inconvenient maintenance associated with traditional ground-source heat pumps. It increases the penetration rate of renewable energy, reduces resource waste, and achieves energy conservation and emission reduction, making it a reliable clean energy utilization technology. This invention can utilize abandoned mines, caves, etc., as deep wells and tunnels, reducing system construction costs. It has a small footprint and flexible site selection, making it suitable for large-scale promotion in areas with concentrated new energy sources in my country, as well as distributed applications in densely populated urban areas with limited land. Attached Figure Description

[0013] Figure 1This is a schematic diagram of the structure of the present invention.

[0014] Figure 2 This is a schematic diagram of the shaft outside the track.

[0015] Figure 3 A schematic diagram of the heating (cooling) operation of a heat pump heating (cooling) unit.

[0016] Figure 4 A schematic diagram of the cooling operation of a heat pump heating (cooling) unit.

[0017] Figure 5 This is a schematic diagram of the shaft inside the track.

[0018] In the diagram: 1. Shaft, 2. Tunnel, 3. Above-ground track, 4. Underground track, 5. Support beam, 6. Support beam, 7. Electric generator, 8. Winch, 9. Heavy load carrier, 10. Compressor, 11. Condenser / evaporator, 12. Throttling valve, 13. Four-way valve, 91. Heat exchange coil, 92. Temperature sensor. Detailed Implementation

[0019] The following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an integrated energy system combining underground gravity energy storage and a heat pump according to the present invention.

[0020] See Figure 1 and Figure 2 This invention discloses an integrated energy system combining underground gravity energy storage and a heat pump, comprising an underground gravity energy storage unit and a heat pump heating (cooling) unit. The underground gravity energy storage unit includes a shaft 1, a tunnel 2, an upper track 3, a lower track 4, a support beam frame 5, a support beam 6, an electric generator 7, a winch 8, and a weight carrier 9. The upper track 3 is installed on the ground and is circular with a straight section. The two ends share the same straight section, which extends to the shaft 1 opening (the shaft 1 and tunnel 2 can be natural caves or abandoned mine shafts). The tunnel may be constructed by manual excavation); the lower track 4 is installed in the tunnel 2 (its structure and dimensions are the same as the upper track 3), the track is circular, with a straight section, the beginning and end share the same straight section, which extends to the bottom of the shaft 1; the support beam frame 5 is installed at the shaft opening of the shaft 1, and the support beam 6 is movably connected to the support beam frame 5 (the support beam 6 can move along the support beam frame 5) and is located above the shaft opening of the shaft 1; the electric generator 7 and the winch 8 are installed on the support beam 6; the height of the support beam frame 5 and the support beam 6 is higher than the height of the heavy load carrier 9.

[0021] See Figure 3 and Figure 4The heat pump heating (cooling) unit is located next to the ground track 3 and includes a compressor 10, a condenser / evaporator 11, and a heat exchange coil 91. The heat exchange coil 91 is located inside the heavy carrier 9, with one end connected to the first port of the four-way valve 13 and the other end connected to the throttle valve 12, the first side of the condenser / evaporator 11, and the third port of the four-way valve 13 in sequence. The inlet and outlet of the compressor 10 are connected to the second and fourth ports of the four-way valve 13, respectively. The second side of the condenser / evaporator 11 is connected to the cold / heat user.

[0022] The load carrier 9 is filled with water and equipped with a temperature sensor 92 to monitor and record the water temperature inside the load carrier 9. The load carrier 9 is equipped with a hanging device to facilitate the lifting and lowering of the winch 8. There are multiple load carriers 9.

[0023] Working principle: When encountering a period of low electricity demand and energy storage is needed, the heavy carrier 9 is moved sequentially along the lower track 4 to the bottom of the shaft 1 by automatic driving or trailer traction / push. The electric generator 7 drives the winch 8 to lift the heavy carrier 9 to the top. Then, the heavy carrier 9 is lowered onto the upper track 3 by moving the support beam 6. It is then moved along the track again by automatic driving or trailer traction / push and finally parked at the end of the upper track 3, completing the energy storage.

[0024] When peak electricity demand occurs and energy release is required, the heavy carrier 9 is moved sequentially along the tail of the upper track 3 to directly below the winch 8 via automatic driving or trailer traction / push. The winch 8 lifts the heavy carrier 9, and then the heavy carrier 9 is moved to the shaft opening 1 via the moving support beam 6. The heavy carrier is then lowered. During the descent of the heavy carrier, the electric generator is driven by the winch to generate electricity. After the heavy carrier 9 falls to the lower track 4, it is moved along the track again via automatic driving or trailer traction / push, and finally stops sequentially at the tail of the lower track 4, completing the energy release.

[0025] When heating is required, the refrigerant in the heat pump heating (cooling) unit absorbs heat from the water in the weight carrier 9 through the heat exchange coil 91. It then passes through the four-way valve 13 to the compressor 10 for heating and pressurization. Afterward, it passes through the four-way valve 13 again to the condenser / evaporator 11, where it condenses and releases heat to provide heating to the user. After condensation and liquefaction, the refrigerant passes through the throttling valve 12 for cooling and pressurization, then returns to the heat exchange coil 91 to continue the cycle. When the water temperature in the weight carrier 9 drops to a first set value, or when the weight carrier 9 needs to release energy by gravity, the two ends of the heat exchange coil 91 in the weight carrier 9 are disconnected, and the heat pump heating (cooling) unit replaces it with another weight carrier 9 for connection, then resumes heating.

[0026] When cooling is required, the refrigerant circulation direction is reversed. The refrigerant in the heat pump heating (cooling) unit releases heat to the water source in the weight carrier 9 through the heat coil 91. After the refrigerant condenses and liquefies, it is cooled and depressurized through the expansion valve 12, and then reaches the condenser / evaporator 11 to evaporate and absorb heat, thereby providing cooling to the user. After passing through the four-way valve 13, it reaches the compressor 10 for heating and pressurization, and then passes through the four-way valve 13 again, returning to the heat exchange coil 91 to continue the above cycle. When the water temperature in the weight carrier 91 rises to the second set value, or when the weight carrier 9 needs to release energy by gravity, the two ends of the heat exchange coil in the weight carrier 9 are disconnected, and the heat pump heating (cooling) unit is replaced with another weight carrier 9 for movable connection, and then cooling is provided.

[0027] Gravity energy storage priority or heating (cooling) priority can be selected as needed. When gravity energy storage is prioritized, the entire system ensures the efficient operation of the gravity energy storage system. The movable connection between the heat pump heating (cooling) unit and the heat exchange coil 91 in the heavy object carrier 9 is disconnected when the heavy object carrier 9 needs to release energy by gravity. When heating (cooling) is prioritized, the entire system must ensure the efficient operation of the heat pump heating (cooling) unit. The heavy object carrier 9 fully absorbs the low-temperature underground heat energy in the underground tunnel 2 before carrying out gravity energy storage, and fully releases the low-temperature heat energy on the ground track 3 before carrying out gravity energy release.

[0028] There are two ways to arrange the relative positions of shaft 1 and upper track 3. The first way is to refer to... Figure 2 Shaft 1 is located outside the circle enclosed by the upper track 3; the second type, see [link to other information]. Figure 5 Shaft 1 is located inside the circle enclosed by the upper track 3. Similarly, the relative position of the lower track 4 and shaft 1 is arranged in the same way as the previous two arrangements.

[0029] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments without departing from the technical essence of the present invention shall still fall within the scope of the present invention.

Claims

1. A comprehensive energy system combining underground gravity energy storage and a heat pump, characterized in that: The system includes an underground gravity energy storage unit and a heat pump heating / cooling unit. The underground gravity energy storage unit includes a shaft (1), a tunnel (2), an upper track (3), a lower track (4), a support beam frame (5), a support beam (6), an electric generator (7), a winch (8), and a heavy object carrier (9). The upper track (3) is installed on the ground. The track is circular and has a straight section. The two ends share the same straight section, which extends to the shaft (1) opening. The lower track (4) is installed in the tunnel (2). The track is circular and has a straight section. The two ends share the same straight section, which extends to the bottom of the shaft (1). The support beam frame (5) is installed at the shaft (1) opening. The support beam (6) is movably connected to the support beam frame (5) and located above the shaft (1) opening. The electric generator (7) and the winch (8) are installed on the support beam frame (5). 6) The heat pump heating (cooling) unit is located next to the ground track (3), including a compressor (10), a condenser / evaporator (11), and a heat exchange coil (91). The heat exchange coil (91) is located inside the heavy carrier (9), with one end connected to the first port of the four-way valve (13) and the other end connected to the throttle valve (12), the first side of the condenser / evaporator (11), and the third port of the four-way valve (13) in sequence. The inlet and outlet of the compressor (10) are connected to the second and fourth ports of the four-way valve (13) respectively. The second side of the condenser / evaporator (11) is connected to the cold / heat user. The heavy carrier (9) is filled with water and is equipped with a temperature sensor (92). The heavy carrier (9) is equipped with a hanging device. There are multiple heavy carriers (9). The heat exchange coil (91) of the heavy carrier (9) is disconnected from the heat pump heating / cooling unit.

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