Geothermal heat storage multifunctional heat exchange device

Abstract

The invention relates to a multifunctional geothermal heat storage heat exchange device and belongs to the technical field of geothermal heat exchange, the multifunctional geothermal heat storage heat exchange device comprises a heat exchange module and a heat storage module, the heat exchange module comprises an inner pipe and an outer pipe, fins are spirally welded to the outer wall of the inner pipe, the heat storage module comprises a phase change heat storage tank, and the outer wall of the phase change heat storage tank is wrapped with a second heat preservation layer. The inner pipe is connected with a geothermal pump through a pipeline, the other end of the geothermal pump is connected with a geothermal pipe, the other end of the geothermal pipe extends into a geothermal well, the outer pipe is connected with a circulating pump, the other end of the circulating pump is connected with a heat exchange pipe, and the other end of the heat exchange pipe is connected with equipment needing heat supply. The phase-change heat storage tank and the internal phase-change material are arranged, the phase-change temperature is controlled, heat is efficiently absorbed and released under the proper working condition, the phase-change latent heat and the phase-change performance attenuation rate are limited, it can be guaranteed that the phase-change material can store a large amount of heat energy, continuous supply is met, and long-term stable operation of the phase-change heat storage tank is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of geothermal heat exchange, and particularly to a multifunctional geothermal heat storage and heat exchange device. Background Art

[0002] A heat reservoir refers to a stratum, rock mass or tectonic zone buried underground with effective voids and permeability, in which the stored geothermal fluid can be exploited. A very important feature of a geothermal heat reservoir is that cold water outside the heat reservoir seeps into the hot aquifer, and then passes through the heating zone at the bottom of the heat reservoir, and is heated under the condition of strong and continuous conductive heat flow supply.

[0003] The existing heat exchange devices have insufficient heat storage capacity, and when the geothermal energy supply is unstable, they cannot continuously provide heat energy, resulting in the inability to make better use of geothermal energy during the conversion of geothermal energy. Summary of the Invention

[0004] In view of the above problems in the prior art, the present invention provides a multifunctional geothermal heat storage and heat exchange device, which is achieved through the following technical solutions: A multifunctional geothermal heat storage and heat exchange device includes a heat exchange module and a heat storage module. The heat exchange module includes an inner pipe and an outer pipe. The inner pipe is arranged in a spiral coil, and the outer pipe is sleeved on the outer circle of the inner pipe and is also arranged in a spiral coil. Fins are helically welded on the outer wall of the inner pipe, and a first heat insulation layer is wrapped around the outer circle of the outer pipe. The heat storage module includes a phase change heat storage tank, and a second heat insulation layer is wrapped around the outer wall of the phase change heat storage tank. The inner pipe is connected to a ground heat pump through a pipeline, and the other end of the ground heat pump is connected to a geothermal pipe, and the other end of the geothermal pipe extends into a geothermal well. The outer pipe is connected to a circulation pump, and the other end of the circulation pump is connected to a heat exchange pipe, and the other end of the heat exchange pipe is connected to the equipment that needs heat supply. The heat exchange pipes are evenly distributed in the phase change heat storage tank.

[0005] Further, temperature sensors are installed at the inlet and outlet of the inner pipe, at the inlet and outlet of the outer pipe, on the geothermal pipe at the wellhead of the geothermal well, and on the heat exchange pipes in the phase change heat storage tank. Pressure sensors are installed at the inlet and outlet of the circulation pump, at the inlet and outlet of the ground heat pump, at the inlet and outlet of the inner pipe and the outer pipe, and at the inlet and outlet of the phase change heat storage tank. Flow sensors are installed at the middle position of the geothermal pipe and at the inlet and outlet of the inner pipe.

[0006] Further, electric control valves are installed at the inlet of the inner pipe, at the outlet of the inner pipe, at the outlet of the outer pipe, at the inlet of the heat exchange pipe, and at the outlet of the heat exchange pipe.

[0007] Further, the temperature sensors, pressure sensors, flow sensors and electric control valves are all connected to a controller through signal lines. The controller is a programmable PLC controller, and the controller is installed in a control room.

[0008] Further, the inner pipe has a diameter of 20 - 40 mm, the outer pipe has a diameter of 30 - 50 mm, the spacing between the inner pipe and the outer pipe is 20 - 50 mm, the fin thickness is 1 - 3 mm, the fin spacing is 5 - 10 mm, and the fin height is 10 - 20 mm.

[0009] Further, the first insulation layer and the second insulation layer are made of polyurethane foam plastic. The thermal conductivity of the polyurethane foam plastic is not higher than 0.025 W / (m・K), and the density of the polyurethane foam plastic is between 30 - 50 kg / m³.

[0010] Further, a phase change material is provided in the phase change heat storage tank. The phase change temperature range of the phase change material is 40 - 60 °C, the latent heat of phase change is not less than 150 kJ / kg, and the phase change performance decay rate is not higher than 5%.

[0011] Further, the inner pipe, the outer pipe, the geothermal pipe, and the heat exchange pipe are all made of stainless steel pipes. The chromium content of the stainless steel pipes is not less than 18%, the nickel content of the stainless steel pipes is between 8% - 14%, and the wall thickness of the stainless steel pipes is selected between 2 - 5 mm according to the pressure at different positions.

[0012] Further, the measurement accuracy of the temperature sensor is ±0.5 °C, the measurement accuracy of the pressure sensor is ±0.05 MPa, and the measurement accuracy of the flow sensor is ±1%.

[0013] Further, the controller adopts a modular design. The controller has 8 or more input / output ports and 4 analog input / output ports.

[0014] In summary, the beneficial technical effects of the present invention are as follows: By setting the phase change heat storage tank and the internal phase change material, controlling the phase change temperature, ensuring efficient absorption and release of heat under appropriate working conditions, and limiting the latent heat of phase change and the phase change performance decay rate, it can ensure that the phase change material can store a large amount of thermal energy, meet continuous supply, and ensure the long-term stable operation of the phase change heat storage tank; by arranging the inner pipe and the outer pipe in a spiral coil, the heat exchange path is extended, and the heat exchange efficiency is improved; by setting the fins, the heat exchange area is increased, and by limiting the thickness, spacing, and height of the fins, it can effectively guide the geothermal medium to form turbulence, improve the heat exchange efficiency, and ensure that geothermal energy can be fully utilized; through the temperature sensor, pressure sensor, and flow sensor, the temperature, pressure, and flow data at various positions during the operation of the device are collected in real time to ensure that the operation state of the device can be accurately grasped; by using stainless steel pipes, corrosion during the working process can be avoided, the service life can be guaranteed, and the maintenance cost and the device replacement frequency can be reduced. Description of the Drawings

[0015] Figure 1 It is a schematic diagram for showing the overall structure of the present invention.

[0016] Figure 2 It is a schematic diagram for showing the structures of the inner tube, outer tube and fins.

[0017] Figure 3 It is a top view for showing the heat exchange module.

[0018] Figure 4 It is a bottom view for showing the heat exchange module.

[0019] Figure 5 It is a control flow chart for showing the controller.

[0020] Reference numerals: 1, inner tube; 2, outer tube; 3, fins; 4, first heat insulation layer; 5, phase change heat storage tank; 6, second heat insulation layer; 7, ground heat pump; 8, geothermal pipe; 9, circulation pump; 10, heat exchange pipe; 11, temperature sensor; 12, pressure sensor; 13, flow sensor; 14, electric control valve; 15, controller. Detailed implementation manners

[0021] The present invention will be further described in detail below with reference to the accompanying drawings.

[0022] Embodiment As Figures 1-5 shown, a geothermal energy storage and multi-functional heat exchange device disclosed by the present invention includes a heat exchange module and a heat storage module. The heat exchange module includes an inner tube 1 for passing geothermal medium and an outer tube 2 for passing heat-required medium. The inner tube 1 is arranged as a spiral coil pipe, and the outer tube 2 is sleeved on the outer circle of the inner tube 1 and is also arranged as a spiral coil pipe. Fins 3 are spirally welded on the outer wall of the inner tube 1. A first heat insulation layer 4 is wrapped on the outer circle of the outer tube 2. The heat storage module includes a phase change heat storage tank 5, and a second heat insulation layer 6 is wrapped on the outer wall of the phase change heat storage tank 5. The inner tube 1 is connected to a ground heat pump 7 through a pipeline, the other end of the ground heat pump 7 is connected to a geothermal pipe 8, and the other end of the geothermal pipe 8 extends into a geothermal well. The outer tube 2 is connected to a circulation pump 9, the other end of the circulation pump 9 is connected to a heat exchange pipe 10, and the other end of the heat exchange pipe 10 is connected to a device that needs heat supply. The heat exchange pipes 10 are uniformly distributed in the phase change heat storage tank 5.

[0023] Temperature sensors 11 are installed at the inlet and outlet of the inner tube 1, at the inlet and outlet of the outer tube 2, on the geothermal pipe 8 at the wellhead of the geothermal well, and on the heat exchange pipes 10 in the phase change heat storage tank 5. Pressure sensors 12 are installed at the inlet and outlet of the circulation pump 9, at the inlet and outlet of the ground heat pump 7, at the inlet and outlet of the inner tube 1 and the outer tube 2, and at the inlet and outlet of the phase change heat storage tank 5. Flow sensors 13 are installed at the middle position of the geothermal pipe 8 and at the inlet and outlet of the inner tube 1.

[0024] Electric control valves 14 are installed at the inlet of the inner pipe 1, the outlet of the inner pipe 1, the outlet of the outer pipe 2, the inlet of the heat exchange pipe 10, and the outlet of the heat exchange pipe 10.

[0025] The temperature sensor 11, the pressure sensor 12, the flow sensor 13, and the electric control valve 14 are all connected to a controller 15 through signal lines. The controller 15 is a programmable PLC controller, and the controller 15 is installed in the control room.

[0026] The inner pipe 1 has a diameter of 20 - 40 mm, the outer pipe 2 has a diameter of 30 - 50 mm, the distance between the inner pipe 1 and the outer pipe 2 is 20 - 50 mm, the fin 3 has a thickness of 1 - 3 mm, the fin 3 spacing is 5 - 10 mm, and the fin 3 height is 10 - 20 mm.

[0027] The first insulation layer 4 and the second insulation layer 6 are made of polyurethane foam plastic. The thermal conductivity of the polyurethane foam plastic is not higher than 0.025 W / (m·K), and the density of the polyurethane foam plastic is between 30 - 50 kg / m³.

[0028] A phase change material is provided in the phase change heat storage tank 5. The phase change temperature range of the phase change material is 40 - 60 °C, the phase change latent heat is not less than 150 kJ / kg, and the phase change performance decay rate is not higher than 5%. This ensures a stable and efficient heat storage effect.

[0029] The inner pipe 1, the outer pipe 2, the geothermal pipe 8, and the heat exchange pipe 10 are all made of stainless steel pipes. The chromium content of the stainless steel pipes is not less than 18%, the nickel content of the stainless steel pipes is between 8% - 14%, and the wall thickness of the stainless steel pipes is selected between 2 - 5 mm according to the pressure at different positions. This can effectively resist the corrosion of geothermal fluid and working medium.

[0030] The measurement accuracy of the temperature sensor 11 is ±0.5 °C, the measurement accuracy of the pressure sensor 12 is ±0.05 MPa, and the measurement accuracy of the flow sensor 13 is ±1%.

[0031] The controller 15 adopts a modular design. The controller 15 has 8 or more input / output ports and 4 analog input / output ports.

[0032] Specific implementation mode of this example: Turn on the power supply. The controller 15 initializes the connection status of the circulation pump 9, the ground heat pump 7, and all temperature sensors 11, pressure sensors 12, flow sensors 13, and electric control valves 14. Start the ground heat pump 7 to extract geothermal fluid from the geothermal well and send it into the inner pipe 1. At the same time, start the circulation pump 9 to make the working medium circulate between the outer pipe 2 and the heat exchange pipe 10 in the phase change heat storage tank 5. The geothermal fluid exchanges heat with the working medium in the outer pipe 1. After the working medium absorbs the heat of the geothermal fluid, its temperature rises. During this process, the temperature sensor 11, pressure sensor 12, and flow sensor 13 respectively monitor parameters such as temperature, pressure, and flow in real time, and transmit the data to the controller 15. The controller 15 adjusts the flow rates of the ground heat pump 7 and the circulation pump 9 and the opening degree of the electric control valve 14 according to these parameters to ensure the efficient progress of the heat exchange process. When the temperature of the working medium reaches the set value, the controller 15 controls the circulation pump 9 to let the working medium enter the heat exchange pipe 10 in the phase change heat storage tank 5 to heat the phase change material to the phase change temperature, causing it to undergo a phase change and store heat. During the heat storage process, the controller 15 adjusts the flow rate of the working medium through the electric control valve 14 and the circulation pump 9 according to the change of the temperature data in the phase change heat storage tank 5 to control the heat storage speed. When heat energy is required at the user end, the controller 15 controls the phase change material in the phase change heat storage tank 5 to release heat and heat the working medium. The working medium transports the heat to the user end to achieve the heating function. During the heating process, the controller adjusts the flow rate and temperature of the working medium according to the temperature demand of the user end to ensure the stability and comfort of heating.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than 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 they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A geothermal heat storage multifunctional heat exchange device, comprising a heat exchange module and a heat storage module, characterized in that: The heat exchange module comprises an inner tube (1) and an outer tube (2), wherein the inner tube (1) is arranged in a spiral coil, and the outer tube (2) is sleeved on the outer ring of the inner tube (1) and is also arranged in a spiral coil. The outer wall of the inner tube (1) is spirally welded with fins (3), and the outer ring of the outer tube (2) is wrapped with a first thermal insulation layer (4). The heat storage module comprises a phase change thermal storage tank (5), and the outer wall of the phase change thermal storage tank (5) is wrapped with a second thermal insulation layer (6). The inner tube (1) is connected to a geothermal pump (7) through a pipeline, and the other end of the geothermal pump (7) is connected to a geothermal pipe (8), and the other end of the geothermal pipe (8) extends into a geothermal well. The outer tube (2) is connected to a circulation pump (9), and the other end of the circulation pump (9) is connected to a heat exchange pipe (10), and the other end of the heat exchange pipe (10) is connected to a device that requires heat supply, and the heat exchange pipe (10) is evenly distributed in the phase change thermal storage tank (5).

2. A geothermal heat storage multifunctional heat exchange device according to claim 1, characterized in that: Temperature sensors (11) are installed at the inlet and outlet of the inner tube (1), the inlet and outlet of the outer tube (2), the geothermal tube (8) at the wellhead of the geothermal well, and the heat exchange tube (10) in the phase change heat storage tank (5); pressure sensors (12) are installed at the inlet and outlet of the circulation pump (9), the inlet and outlet of the geothermal pump (7), the inlet and outlet of the inner tube (1) and the outer tube (2), and the inlet and outlet of the phase change heat storage tank (5); and flow sensors (13) are installed at the middle position of the geothermal tube (8) and the inlet and outlet of the inner tube (1).

3. A geothermal heat storage multifunctional heat exchange device according to claim 2, characterized in that: The inlet of the inner tube (1), the outlet of the inner tube (1), the outlet of the outer tube (2), the inlet of the heat exchange tube (10) and the outlet of the heat exchange tube (10) are all equipped with electric control valves (14).

4. A geothermal heat storage multifunctional heat exchange device according to claim 3, characterized in that: The temperature sensor (11), the pressure sensor (12), the flow sensor (13) and the electric control valve (14) are all connected to a controller (15) via signal lines. The controller (15) is a programmable PLC controller. The controller (15) is installed in a control room.

5. The geothermal heat storage multifunctional heat exchange device according to claim 1, characterized in that: The diameter of the inner tube (1) is 20-40 mm, the diameter of the outer tube (2) is 30-50 mm, the spacing between the inner tube (1) and the outer tube (2) is 20-50 mm, the thickness of the fin (3) is 1-3 mm, the spacing between the fins (3) is 5-10 mm, and the height of the fin (3) is 10-20 mm.

6. The geothermal heat storage multifunctional heat exchange device according to claim 1, characterized in that: The first thermal insulation layer (4) and the second thermal insulation layer (6) are made of polyurethane foam plastics, the thermal conductivity of the polyurethane foam plastics is not higher than 0.25 W / (m·K), and the density of the polyurethane foam plastics is between 30-50 kg / m³.

7. The geothermal heat storage multifunctional heat exchange device according to claim 1, characterized in that: The phase change heat storage tank (5) is provided with a phase change material, the phase change temperature range of the phase change material is 40-60° C., the phase change latent heat is not less than 150 kJ / kg, and the phase change performance attenuation rate is not higher than 5%.

8. The geothermal heat storage multifunctional heat exchange device according to claim 1, characterized in that: The inner tube (1), the outer tube (2), the geothermal tube (8) and the heat exchange tube (10) are all made of stainless steel tubes. The chromium content of the stainless steel tubes is not less than 18%, the nickel content of the stainless steel tubes is between 8% and 14%, and the wall thickness of the stainless steel tubes is selected between 2 and 5 mm according to the pressure at different positions.

9. The geothermal heat storage multifunctional heat exchange device according to claim 2, characterized in that: The measurement accuracy of the temperature sensor (11) is ±0.5°C, the measurement accuracy of the pressure sensor (12) is ±0.5MPa, and the measurement accuracy of the flow sensor (13) is ±1%.

10. The geothermal heat storage multifunctional heat exchange device according to claim 4, characterized in that: The controller (15) adopts a modular design, and is provided with 8 or more input and output ports and 4 analog input and output ports.

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