High-voltage electric heater and energy storage system

Abstract

The application discloses a high-voltage electric heater and an energy storage system, wherein the electric heater comprises a plurality of heat pipes and electric heating elements; the heat pipes are filled with high-temperature insulating heat exchange medium; the heat pipes comprise evaporation zones, overheating zones and heat transfer zones; the evaporation zones are provided with liquid-phase heat exchange medium; the overheating zones are provided with saturated evaporation gas-phase heat exchange medium; and the heat transfer zones are provided with gas-phase heat exchange medium; the heat pipes of the evaporation zones and the overheating zones are respectively provided with electric heating elements, and the electric heating elements are electrically connected with high-voltage electric wires; and the heat transfer medium directly contacts with the heat pipes. The electric heater can be directly connected with high-voltage wires in the evaporation zones and the overheating zones of the heat pipes, so that the power distribution cost of the electric system is greatly reduced, the electric heating power of each electric heating element is enhanced, the heating power of the electric heater is increased, and the power equipment cost of the electric heater is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of energy storage, and particularly relates to a high-voltage electric heater and an energy storage system. BACKGROUND

[0002] Energy storage technology is a key technology for achieving the goal of "carbon peak and carbon neutralization", and heat storage is one of the mainstream technologies in energy storage technology. Molten salt is one of high-temperature heat storage mediums, and heat storage is to convert electric energy into heat energy of molten salt for storage, which can be converted into electric energy for release or directly release heat energy for industrial production activities. However, in the process of converting electric energy into heat energy, the problem of high-temperature insulation is faced. Therefore, the voltage grade of the electric heating molten salt equipment is usually low, which cannot directly use the voltage of large industrial electricity, and a large number of voltage transformation and power distribution equipment are needed to reduce the voltage grade required by the equipment, greatly increasing the cost of power distribution equipment. SUMMARY

[0003] To solve the above technical problems, the application provides a high-voltage electric heater and an energy storage system, which can directly connect high-voltage wiring in the evaporation zone and the overheating zone of the heat pipe, greatly reducing the power distribution cost of the electrical system, and at the same time, enhancing the electric heating power of each electric heating element, thereby increasing the heating power of the electric heater and reducing the power equipment cost of the electric heater.

[0004] To achieve the above purpose, the technical scheme of the application is as follows:

[0005] A high-voltage electric heater for heating heat storage medium, comprising a plurality of heat pipes and electric heating elements, the heat pipes being filled with high-temperature insulation heat exchange medium, the heat pipes comprising an evaporation zone, an overheating zone and a heat transfer zone, the evaporation zone being provided with liquid-phase heat exchange medium, the overheating zone being provided with saturated evaporation gas-phase heat exchange medium, and the heat transfer zone being provided with gas-phase heat exchange medium;

[0006] The electric heating elements are respectively arranged in the heat pipes of the evaporation zone and the overheating zone, and the electric heating elements are electrically connected to high-voltage electric wiring;

[0007] The heat storage medium directly contacts the heat transfer zone of the heat pipe.

[0008] In order to enhance the heat transfer capacity, a plurality of heat transfer fins are arranged on the heat pipe of the heat transfer zone.

[0009] The heat storage medium exchanges heat in the heat transfer zone of the heat pipe, the heat pipe of the heat transfer zone is arranged in a heat storage medium heating cavity, and the heat storage medium heating cavity is provided with a heat storage medium inlet and a heat storage medium outlet.

[0010] The heat pipe has an insulating shell, and the material of the insulating shell is alumina or magnesia.

[0011] The high-temperature insulation heat exchange medium is a high-boiling organic substance.

[0012] The heat storage medium is a molten salt.

[0013] The application further provides an energy storage system comprising the high-power high-voltage electric heater, the low-temperature heat storage medium storage tank and the high-temperature heat storage medium storage tank, the heat storage medium outlet of the electric heater is communicated with the inlet of the high-temperature heat storage medium storage tank, and the outlet of the low-temperature heat storage medium storage tank is communicated with the heat storage medium inlet of the electric heater.

[0014] Compared with the prior art, the application has the following advantages and positive effects:

[0015] The high-voltage electric heater in the embodiment of the application adopts multiple heat pipes for heat transmission, the heat pipes are filled with high-temperature insulation heat exchange medium, each heat pipe is divided into an evaporation zone, a superheating zone and a heat transfer zone, the heat exchange medium in the evaporation zone is in a liquid phase state, the heat exchange medium in the superheating zone is in a saturated evaporation gas state, and the heat exchange medium in the heat transfer zone is in a gas phase state, and the electric heating element connected with the high-voltage wire is arranged on the heat pipes in the evaporation zone and the superheating zone. The liquid phase state heat exchange medium in the heat pipe is heated and warmed by the electric heating element, evaporates to form saturated evaporation gas, is further heated by the heating zone electric heating element in the superheating zone, removes the liquid phase medium contained in the gas, and the heated saturated evaporation gas transmits heat to the heat storage medium contacting the heat pipe in the heat transfer zone. The insulation performance of the gas is generally better than that of the solid and liquid, mainly because the distance between the molecules or atoms of the gas is large, and it is difficult to transmit electric charge. Therefore, the superheated gas in the heat transfer zone has excellent insulation performance, and even if the electric charge leaks to the heat exchange medium, the gas in the superheating zone can prevent the electric charge from leaking to the flowing heat storage medium. Therefore, the electric heating element in the evaporation zone and the superheating zone can use high-voltage electricity.

[0016] Since the electric heater can use high-voltage wiring, the cost of power distribution of the electrical system is greatly reduced. At the same time, the use of high-voltage level enhances the electric heating power of a single electric heating element, increases the heating power of a single device, and reduces the cost of unit power equipment.

[0017] At the same time, the high-voltage electric heater of the application has multiple heat pipes, and each heat pipe has an electric heating element, so it can also play a role in voltage division, reducing the voltage of each electric resistance element and further ensuring safety.

[0018] Another embodiment of the application further provides an insulation shell arranged outside the heat pipe, further ensuring insulation. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a structural schematic diagram of the high-voltage electric heater of the embodiment 1 of the application.

[0020] BRIEF DESCRIPTION OF DRAWINGS 1 - Evaporation zone connection; 2 - Superheat zone connection; 3 - Evaporation zone; 4 - Superheat zone; 5 - Heat transfer zone; 6 - First electric heating element; 7 - Second electric heating element; 8 - Insulating housing; 9 - Heat transfer fin; 10 - Heat storage medium inlet; 11 - Heat storage medium outlet; 12 - Heating chamber; 13 - Ground connection; 14 - Heat pipe. DETAILED DESCRIPTION

[0021] A high voltage electric heater according to the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will be more apparent from the following description.

[0022] Example 1

[0023] Reference Figure 1 A high voltage electric heater for heating a heat storage medium, comprising a plurality of heat pipes 14, the heat pipes 14 being filled with a high temperature insulating heat transfer medium, the heat pipes 14 comprising an evaporation zone 3, a superheat zone 4 and a heat transfer zone 5, the evaporation zone 3 being provided with the heat transfer medium in a liquid phase, the superheat zone 4 being provided with the heat transfer medium in a saturated vapor phase, the heat transfer zone 5 being provided with the heat transfer medium in a vapor phase;

[0024] The heat pipes 14 of the evaporation zone 3 and the superheat zone 4 are provided with electric heating elements, the electric heating elements of the evaporation zone 3 being first electric heating elements 6, the electric heating elements of the superheat zone 4 being second electric heating elements 7, the first electric heating elements 6 of all heat pipes 14 being connected together and connected to a high voltage electric connection via an evaporation zone connection 1, the second electric heating elements 7 of all heat pipes 14 being connected together and connected to a high voltage electric connection via a superheat zone connection 2, each heat pipe 14 being connected to ground via a ground connection 13.

[0025] The heat transfer zone 5 of the heat pipes 14 is in direct contact with the heat storage medium, in the present embodiment the heat transfer zone 5 of the heat pipes 14 is provided in a heat insulating heating chamber 12, the heating chamber 12 being provided with a heat storage medium inlet 10 and a heat storage medium outlet 11, the heat storage medium flowing through the heating chamber 12.

[0026] The heat transfer medium in the heat pipes 14 in a liquid phase is heated by the first electric heating elements 6 to a temperature at which it evaporates to form a saturated vapor, the saturated vapor is further heated by the second electric heating elements 7 in the superheat zone 4 to remove any liquid phase medium from the vapor, the heated saturated vapor in the heat transfer zone 5 transfers heat to the heat storage medium in contact with the heat pipes 14. Gases generally have better insulating properties than solids and liquids, mainly because the distance between the molecules or atoms of a gas is larger and charge transfer is more difficult. The superheated vapor in the heat transfer zone 5 therefore has excellent insulating properties, even if some charge leaks to the heat transfer medium, the gas in the superheat zone 4 prevents the charge from leaking to the flowing heat storage medium. It is therefore possible to use high voltage electricity for the electric heating elements in the evaporation zone 3 and the superheat zone 4.

[0027] At the same time, the electric heater has a plurality of heat pipes 14, and each heat pipe 14 has an electric heating element, so that the electric heating element can also play a role of voltage division, and the voltage of each electric resistance element is reduced, and the safety is further ensured.

[0028] In order to further ensure the insulation, each heat pipe 14 has an insulating shell 8, and the material of the insulating shell 8 is an insulating material of alumina or magnesia.

[0029] Therefore, the insulation of the embodiment is ensured from two aspects, first, the insulating shell 8 has insulation, and second, the overheated gas of the heat transfer area 5 further prevents the leakage of electric charges to the flowing heat storage medium.

[0030] In order to enhance the heat transfer capacity, a plurality of heat transfer fins 9 are arranged on the heat pipe 14 of the heat transfer area 5.

[0031] The high-temperature insulation heat transfer medium of the embodiment is a high-boiling organic matter, such as a paraffin mixture.

[0032] The heat storage medium in the embodiment is a molten salt.

[0033] Embodiment 2

[0034] An energy storage system, comprising the high-voltage electric heater of embodiment 1, a low-temperature heat storage medium storage tank and a high-temperature heat storage medium storage tank, the heat storage medium outlet 11 of the electric heater is communicated with the inlet of the high-temperature heat storage medium storage tank, and the outlet of the low-temperature heat storage medium storage tank is communicated with the heat storage medium inlet 10 of the electric heater.

[0035] The embodiments of the application are described in detail above in combination with the drawings, but the application is not limited to the above-described embodiments. Even if various changes are made to the application, if the changes belong to the scope of the claims of the application and equivalent technologies, they still fall within the protection scope of the application.

Claims

1. A high-voltage electric heater for heating a heat storage medium, characterized in that, It includes several heat pipes and electric heating elements. The heat pipes are filled with a high-temperature insulating heat exchange medium. The heat pipes include an evaporation zone, a superheating zone and a heat transfer zone. The evaporation zone is provided with a heat exchange medium in a liquid phase. The superheating zone is provided with a heat exchange medium in a saturated evaporation gas phase. The heat transfer zone is provided with a heat exchange medium in a gas phase phase. The heat pipes in the evaporation zone and the superheated zone are respectively equipped with the electric heating elements, which are electrically connected to high-voltage wiring; the heat storage medium is in direct contact with the heat transfer zone of the heat pipe; The electric heating element in the evaporation zone heats the heat exchange medium in the liquid phase. The heat exchange medium in the liquid phase is heated and evaporated to form saturated evaporation gas, which is further heated by the electric heating element in the superheated zone to remove the liquid phase medium contained in the saturated evaporation gas. The heated saturated evaporation gas transfers heat to the heat storage medium in contact with the heat pipe in the heat transfer zone. The heat pipe has an insulating outer shell.

2. The high-voltage electric heater according to claim 1, characterized in that, The insulating outer shell is made of aluminum oxide or magnesium oxide.

3. The high-voltage electric heater according to claim 1, characterized in that, Multiple heat transfer fins are arranged on the heat pipe in the heat transfer section.

4. The high-voltage electric heater according to claim 1, characterized in that, The heat pipe of the heat transfer zone is installed in the heat storage medium heating cavity, which is provided with a heat storage medium inlet and a heat storage medium outlet.

5. The high-voltage electric heater according to claim 1, characterized in that, The heat storage medium is molten salt.

6. An energy storage system, characterized in that, The invention includes a high-pressure electric heater, a low-temperature thermal storage medium tank, and a high-temperature thermal storage medium tank according to any one of claims 1-5, wherein the thermal storage medium outlet of the electric heater is connected to the inlet of the high-temperature thermal storage medium tank, and the outlet of the low-temperature thermal storage medium tank is connected to the thermal storage medium inlet of the electric heater.

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