A magnetically controlled phase change heat storage device and method

Abstract

An embodiment of the present invention provides a magnetically controlled phase change heat storage device and method, wherein the device includes a tank body, a heat transfer mechanism, a temperature sensor, a magnetic field generator and a controller; the tank body is filled with a magnetic phase change material; the heat transfer mechanism partially passes through the tank body; the temperature sensor is arranged in the tank body; the temperature sensor and the magnetic field generator are both connected to the controller, and the controller is used to control the magnetic field generated by the magnetic field generator according to the temperature value inside the tank body measured by the temperature sensor, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank body; the heat energy storage or release process can be accelerated or decelerated according to the instantaneous temperature difference, so that the phase change energy storage has adaptive active controllability, thereby expanding the range of applicable working conditions.

Description

Technical Field

[0001] The embodiments of the present invention relate to, but are not limited to, the field of energy storage, and in particular to a magnetically controlled phase change heat storage device and method. Background Art

[0002] Latent heat storage is an energy storage technology based on phase change materials. It is primarily categorized as chemical, sensible, and latent. Chemical storage boasts a high thermal storage density, but its instability makes the storage process somewhat uncontrollable. While sensible storage has a large market, its low thermal storage density makes it difficult to store large amounts of heat. Latent heat storage, as a highly efficient, low-carbon energy storage technology, has attracted widespread attention due to its high energy storage density and stability. However, the low thermal conductivity of phase change materials prolongs the heat storage and release process, limiting the energy utilization efficiency of latent heat storage systems. Therefore, passive heat transfer enhancement techniques such as adding fins, nanoparticles, and porous media are being used to improve the heat transfer performance of phase change materials. Existing thermal storage tanks can only store or release heat within a single temperature range, making them unsuitable for long-term peak load and heat supply balancing under various operating conditions. Furthermore, the low thermal conductivity of phase change materials results in low efficiency during short-term transient energy storage or release. Summary of the Invention

[0003] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0004] Embodiments of the present invention provide a magnetically controlled phase change heat storage device and method.

[0005] In a first aspect of the present invention, a magnetically controlled phase change heat storage device comprises:

[0006] A tank body filled with a magnetic phase change material;

[0007] a heat transfer mechanism, wherein a portion of the heat transfer mechanism passes through the tank;

[0008] A temperature sensor is disposed in the tank;

[0009] magnetic field generator;

[0010] The temperature sensor and the magnetic field generator are both connected to the controller, and the controller is used to control the magnetic field generated by the magnetic field generator according to the temperature value inside the tank measured by the temperature sensor, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank.

[0011] According to the first aspect of the present invention, the tank body is divided into a plurality of temperature zones having different phase change temperature intervals; each of the temperature zones is correspondingly provided with the temperature sensor and the magnetic field generator.

[0012] According to the first aspect of the present invention, the tank body is provided with a ventilation layer, and the magnetic field generator is located in the ventilation layer.

[0013] According to the first aspect of the present invention, the magnetic field generator includes a coil, and the coil is wound around the outside of the magnetic phase change material.

[0014] According to the first aspect of the present invention, the tank body is provided with a heat insulating layer, and the heat insulating layer is filled with a heat insulating material.

[0015] According to the first aspect of the present invention, the magnetic phase change material includes paraffin wax and paramagnetic ferrosoferric oxide.

[0016] According to the first aspect of the present invention, the particle size of the paramagnetic ferrosoferric oxide is in the range of 5-100 nm; and the mass fraction of the paramagnetic ferrosoferric oxide is in the range of 0-4 wt.%.

[0017] According to the first aspect of the present invention, the heat transfer mechanism includes a heat medium transfer pipe, a water pump and a flow valve, and the flow valve and the water pump are provided on the heat medium transfer pipe.

[0018] According to the first aspect of the present invention, the heat medium transmission pipe includes a first pipe and a second pipe, the first pipe is located inside the tank body, the second pipe is located outside the tank body, and the thermal conductivity of the first pipe is higher than that of the second pipe.

[0019] The second aspect of the present invention is a heat storage method, which is applied to the magnetically controlled phase change heat storage device as described in the first aspect of the present invention; the method includes: obtaining the temperature value inside the tank through a temperature sensor; controlling the magnetic field generated by the magnetic field generator according to the temperature value, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank.

[0020] The above solution has at least the following beneficial effects: heat is stored in a magnetic phase-change material, the temperature inside the tank is measured by a temperature sensor, and based on the temperature feedback from the temperature sensor, a magnetic field is generated by a magnetic field generator. This magnetic field magnetizes the magnetic phase-change material, creating a thermomagnetic convection effect, causing the magnetic phase-change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank. The ability to accelerate or decelerate the thermal energy storage or release process based on instantaneous temperature differences provides phase-change energy storage with adaptive active control, expanding its applicable operating conditions.

[0021] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation to the technical solution of the present invention.

[0023] Figure 1 This is a structural diagram of a magnetically controlled phase change heat storage device;

[0024] Figure 2 It is a schematic diagram of the internal structure of the tank;

[0025] Figure 3 This is a schematic diagram of the internal structure of the upper vacant layer. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0027] It should be noted that although the device schematics illustrate functional module divisions and the flowcharts illustrate logical sequences, in certain circumstances, the steps shown or described may be performed in a sequence that differs from the module divisions in the device or the sequence in the flowcharts. The terms "first," "second," and the like in the specification, claims, or accompanying drawings are used to distinguish similar items and are not necessarily used to describe a specific sequence or precedence.

[0028] The present invention provides a magnetically controlled phase-change heat storage device and method. Heat is stored in a magnetic phase-change material 110. A temperature sensor 300 measures the temperature inside the tank 100. Based on the temperature feedback from the temperature sensor 300, a magnetic field generator 400 generates a magnetic field. This magnetic field magnetizes the magnetic phase-change material 110, creating a thermomagnetic convection effect. This causes the magnetic phase-change material 110 to undergo a phase change, storing or releasing energy, thereby regulating the temperature inside the tank 100.

[0029] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0030] An embodiment of the present invention provides a magnetically controlled phase-change heat storage device.

[0031] Reference Figure 1 The magnetic controlled phase change heat storage device includes a tank body 100, a heat transmission mechanism 200, a temperature sensor 300, a magnetic field generator 400 and a controller 500.

[0032] Among them, the tank body 100 is filled with a magnetic phase change material 110; the heat transfer mechanism 200 partially passes through the tank body 100; the temperature sensor 300 is arranged in the tank body 100; the temperature sensor 300 and the magnetic field generator 400 are both connected to the controller 500, and the controller 500 is used to control the magnetic field generated by the magnetic field generator 400 according to the temperature value inside the tank body 100 measured by the temperature sensor 300, so that the magnetic field magnetizes the magnetic phase change material 110 to form a thermomagnetic convection effect, so that the magnetic phase change material 110 undergoes phase change to store or release energy, thereby regulating the temperature inside the tank body 100.

[0033] In this embodiment, heat is stored in the magnetic phase-change material 110, the temperature inside the tank 100 is measured by the temperature sensor 300, and the temperature collector 510 collects the temperature values ​​measured by the multiple temperature sensors 300. Based on the temperature values ​​fed back by the temperature sensors 300, a computer performs calculations according to a preset program and outputs a control signal. By adjusting the current supplied by the DC power supply 520, the magnetic field generator 400 is controlled to generate a magnetic field. This magnetic field magnetizes the magnetic phase-change material 110, creating a thermomagnetic convection effect, causing the magnetic phase-change material 110 to undergo phase change, storing or releasing energy, thereby regulating the temperature inside the tank 100. The ability to accelerate or decelerate the thermal energy storage or release process based on instantaneous temperature differences gives the phase-change energy storage system adaptive active control, expanding its applicable operating range.

[0034] It should be noted that phase change materials refer to substances that change state and generate latent heat while maintaining constant temperature. The process of changing physical properties is called a phase change, during which the phase change material absorbs or releases a large amount of latent heat. Magnetic phase change material 110 can be magnetized through magnetic field control, accelerating or decelerating the thermal energy storage or release process.

[0035] In some embodiments of the present invention, the tank body 100 is divided into a plurality of temperature zones having different phase change temperature intervals; each temperature zone is correspondingly provided with a temperature sensor 300 and a magnetic field generator 400 .

[0036] In this embodiment, the tank body 100 is divided into multiple temperature zones by partitions, and different temperature zones have different phase transition temperature intervals. Specifically, the tank body 100 is cylindrical, and the partitions are placed horizontally, thereby dividing the tank body 100 into multiple upper and lower cylindrical temperature zones.

[0037] Specifically, there are three partitions: an upper partition 601, a middle partition 602, and a lower partition 603. The space between the upper partition 601 and the middle partition 602 is filled with a high-melting-point magnetic phase-change material 110 to form a high-temperature energy storage tank, while the space between the middle partition 602 and the lower partition 603 is filled with a low-melting-point magnetic phase-change material 110 to form a low-temperature energy storage tank. The space above the upper partition 601 is the upper vacant layer, and the space below the lower partition 603 is the bottom vacant layer. Of course, in other embodiments, the interior of the tank body 100 can also be divided into more temperature zones in the longitudinal or transverse directions according to actual operating conditions.

[0038] Each temperature zone is detected by a corresponding temperature sensor 300 and independently controlled by a corresponding magnetic field generator 400, utilizing magnetic fields to control transient phase changes and store or release heat in different temperature ranges. Furthermore, heat can be stored or released in different temperature ranges based on long-term energy peaking needs, providing targeted considerations for efficient energy utilization and energy storage and release under various operating conditions.

[0039] Specifically, when the temperature sensor 300 corresponding to the high-temperature energy storage tank detects that the temperature of the high-temperature energy storage tank is too high or too low, the magnetic field generator 400 corresponding to the high-temperature energy storage tank generates a magnetic field to magnetize the magnetic phase-change material 110 in the high-temperature energy storage tank region, controlling the transient phase change process and storing or releasing heat. However, the magnetic field generated by the magnetic field generator 400 corresponding to the high-temperature energy storage tank does not affect the magnetic phase-change material 110 in the low-temperature region, or only minimally affects the magnetic phase-change material 110 in the low-temperature region.

[0040] When the temperature sensor 300 corresponding to the low-temperature energy storage tank measures that the temperature of the low-temperature energy storage tank is too high or too low, the magnetic field generator 400 corresponding to the low-temperature energy storage tank generates a magnetic field to magnetize the magnetic phase-change material 110 in the low-temperature energy storage tank region, controlling the transient phase change process and storing or releasing heat. However, at this time, the magnetic field generated by the magnetic field generator 400 corresponding to the low-temperature energy storage tank has no effect on the magnetic phase-change material 110 in the high-temperature region, or has only a minimal effect on the magnetic phase-change material 110 in the high-temperature region.

[0041] Specifically, the temperature sensor 300 is a thermocouple. Multiple thermocouples are positioned at different locations within the magnetic phase-change material 110 to more accurately measure the temperature of the magnetic phase-change material 110. The connecting wires of the temperature sensor 300 pass through the upper surface of the upper partition 601 and the lower surface of the lower partition 603 and into the tank 100 to avoid packaging difficulties and leakage of the liquid phase material.

[0042] The magnetic phase change material 110 includes paraffin wax and paramagnetic ferroferric oxide. The paraffin wax has a high phase change latent heat value. The paramagnetic ferroferric oxide has a particle size range of 5-100 nm and a nanoscale structure. The mass fraction of the paramagnetic ferroferric oxide is 0-4 wt.%. Magnetic phase change materials 110 with different phase change temperatures are used in different temperature zones. These phase change temperatures are mainly achieved by paraffin waxes with different melting points.

[0043] Reference Figure 2 In some embodiments of the present invention, the structure of the magnetic phase change heat storage device from the inside out is: a magnetic phase change material layer 110, a heat insulating layer 120, a ventilation layer 130, and a housing 140. The magnetic field generator 400 is located in the ventilation layer 130.

[0044] The magnetic field generator 400 is a coil wound with copper wire, which is located outside the magnetic phase change material 110 layer and further wound around the outer surface of the thermal insulation layer 120. The coil is fixed by a longitudinal fixing structure and a transverse fixing structure.

[0045] When the coil generates a magnetic field during operation, it also generates heat; the ventilation layer 130 is a hollow channel that is connected to the outside world, so that the air outside the tank body 100 can flow through the ventilation layer 130 to cool the coil, thereby preventing the coil temperature from being too high and affecting the temperature of the magnetic phase change material 110 layer.

[0046] The heat insulating layer 120 is filled with a heat insulating material, and the heat insulating layer 120 reduces heat loss during storage or release.

[0047] In some embodiments of the present invention, the heat transfer mechanism 200 includes a heat medium transfer pipe, a water pump 222 and a flow valve 221 . The flow valve 221 and the water pump 222 are disposed on the heat medium transfer pipe.

[0048] In addition, the heat transfer pipe includes a first pipe 211 and a second pipe 212. The first pipe 211 is located inside the tank 100, while the second pipe 212 is located outside the tank 100. The thermal conductivity of the first pipe 211 is higher than that of the second pipe 212. The first pipe 211, made of a high thermal conductivity material, passes through the different temperature zones within the tank 100 through a reserved interface in the partition and is sealed at the interface to facilitate heat exchange between the heat transfer fluid in the heat transfer pipe and the magnetic phase change material 110. The high thermal conductivity of the first pipe 211 facilitates heat exchange between the heat transfer fluid in the first pipe 211 and the magnetic phase change material 110 through the pipe wall of the first pipe 211. The second pipe 212, made of a low thermal conductivity material, forms the inlet pipe and, together with the flow valve 221, controls the input of the heat transfer fluid. The inlet pipe and flow valve 221 are located at the bottom. Furthermore, the second pipe 212 made of a low thermal conductivity material forms an outlet pipe. The outlet pipe and the water pump 222 realize the controlled output of the heat medium. The outlet pipe and the water pump 222 are located at the top.

[0049] Reference Figure 3 Furthermore, the inlet pipe of the first pipe 211 in the bottom empty layer is split into multiple pipes, passing through the middle layer of magnetic phase change material 110. These multiple pipes then merge into a single outlet pipe in the upper empty layer. This multiple pipe heat exchange improves heat exchange efficiency. Furthermore, the upper and bottom empty layers can be filled with insulation material to reduce heat loss during the phase change process.

[0050] The entire tank body 100 is supported by the bracket, which makes the overall structure of the tank body 100 more stable and facilitates the movement of the tank body 100.

[0051] It should be noted that the housing 140 and other mounting structures are made of non-magnetic materials to avoid interference with the magnetic field.

[0052] The embodiment of the second aspect of the present invention provides a heat storage method, which is applied to the magnetic controlled phase change heat storage device of the embodiment of the first aspect of the present invention.

[0053] Methods include:

[0054] Obtaining the temperature value inside the tank 100 through the temperature sensor 300;

[0055] The magnetic field generated by the magnetic field generator 400 is controlled according to the temperature value, so that the magnetic phase change material 110 undergoes phase change to store or release energy.

[0056] Specifically, the temperature value inside the tank 100 is measured by the temperature sensor 300, and the temperature collector 510 collects the temperature values ​​measured by the multiple temperature sensors 300;

[0057] According to the temperature value fed back by the temperature sensor 300, the computer performs calculations according to a preset program and outputs a control signal.

[0058] The computer first calculates the Rayleigh number, which can be calculated according to the following formula: Wherein, g is the acceleration due to gravity, β is the thermal expansion coefficient of the magnetic phase change material 110, l is the characteristic length in the energy storage tank, and Y h -Tc is the dynamic temperature difference measured by the temperature sensor 300 corresponding to each temperature zone. α and v are the thermal diffusivity and kinematic viscosity of the magnetic phase change material 110, respectively. In fluid mechanics, the Rayleigh number is a dimensionless number related to buoyancy-driven convection. When the Rayleigh number of a fluid is below a critical value, heat transfer primarily occurs through conduction. When the Rayleigh number exceeds the critical value, heat transfer primarily occurs through convection.

[0059] The computer then changes the magnetic field parameters generated by the coil by adjusting the current value supplied by the DC power supply 520 based on the Bissaloniki law. The magnetic field parameters are based on: Where B and H are the magnetic induction vector and magnetic field strength vector respectively, is the vacuum permeability, I is the current intensity of the DC power supply 520, ds is the current differential, and r represents the distance vector from the current difference on the coil to any point in space.

[0060] The generation of magnetic field changes the motion behavior of magnetic nanoparticle composite phase change materials by calculating the Kelvin force generated by the magnetic field to regulate the phase change energy storage or release in the high / low temperature energy storage tank. The Kelvin force is expressed as: Among them, M and They are the magnetization vector and the magnetic field intensity gradient respectively. Here, the three coils can be divided into two independent groups of coils to generate a uniform magnetic field or a gradient magnetic field through current changes to generate different magnetic field forces.

[0061] By adjusting the current value supplied by the DC power supply 520, the magnetic field generator 400 is controlled to generate a magnetic field, so that the magnetic field magnetizes the magnetic phase change material 110 to form a thermomagnetic convection effect, causing the magnetic phase change material 110 to undergo phase change to store or release energy, thereby regulating the temperature inside the tank body 100.

[0062] The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the above implementation. Those skilled in the art can also make various equivalent modifications or substitutions under the shared conditions that do not violate the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present invention.

Claims

1. A magnetically controlled phase change heat storage device, characterized in that: include: A tank body filled with a magnetic phase change material; a heat transfer mechanism, wherein a portion of the heat transfer mechanism passes through the tank; A temperature sensor is disposed in the tank; A magnetic field generator, wherein the tank body is divided into a plurality of temperature zones with different phase change temperature intervals; each temperature zone is correspondingly provided with the temperature sensor and the magnetic field generator; a controller, the temperature sensor and the magnetic field generator being connected to the controller, the controller being configured to control the magnetic field generated by the magnetic field generator based on the temperature value inside the tank measured by the temperature sensor, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank; The controller calculates the Rayleigh number to determine whether the form of heat transfer of the magnetic phase change material is heat conduction or convection; changes the magnetic field parameters generated by the coil by adjusting the current value of the DC power supply; and changes the motion behavior of the magnetic phase change material by calculating the Kelvin force generated by the magnetic field to regulate phase change energy storage or release. The Rayleigh number is calculated according to the following formula: , where g is the acceleration due to gravity, is the thermal expansion coefficient of the magnetic phase change material, l is the characteristic length inside the energy storage tank, is the dynamic temperature difference measured by the temperature sensors corresponding to the temperature zones of each layer, and are the thermal diffusivity and kinematic viscosity of the magnetic phase change material, respectively.

2. The magnetically controlled phase change heat storage device according to claim 1, characterized in that: The tank body is provided with a ventilation layer, and the magnetic field generator is located in the ventilation layer.

3. The magnetic controlled phase change heat storage device according to claim 1, characterized in that: The magnetic field generator includes a coil wound around the outside of the magnetic phase change material.

4. The magnetically controlled phase change heat storage device according to claim 1, characterized in that: The tank body is provided with a heat insulating layer, and the heat insulating layer is filled with heat insulating material.

5. The magnetic controlled phase change heat storage device according to claim 1, characterized in that: The magnetic phase change material includes paraffin wax and paramagnetic ferrosoferric oxide.

6. The magnetic controlled phase change heat storage device according to claim 5, characterized in that: The particle size of the paramagnetic ferroferric oxide is in the range of 5-100 nm; and the mass fraction of the paramagnetic ferroferric oxide is in the range of 0-4 wt.%.

7. The magnetic controlled phase change heat storage device according to claim 1, characterized in that: The heat transfer mechanism includes a heat medium transfer pipe, a water pump and a flow valve, and the flow valve and the water pump are arranged on the heat medium transfer pipe.

8. The magnetic controlled phase change heat storage device according to claim 7, characterized in that: The heat medium transmission pipe includes a first pipe and a second pipe, the first pipe is located inside the tank body, the second pipe is located outside the tank body, and the thermal conductivity of the first pipe is higher than the thermal conductivity of the second pipe.

9. A heat storage method, characterized in that: Applicable to the magnetically controlled phase change heat storage device according to any one of claims 1 to 8; the method comprises: obtaining a temperature value inside the tank through a temperature sensor; controlling the magnetic field generated by a magnetic field generator according to the temperature value, so that the magnetic field magnetizes the magnetic phase change material to form a thermomagnetic convection effect, causing the magnetic phase change material to undergo phase change to store or release energy, thereby regulating the temperature inside the tank.

Images