Energy efficiency optimization type power station system based on thermoelectric power generation-photo-thermal coupling

Abstract

The invention provides an energy efficiency optimization type power station system based on thermoelectric power generation-photo-thermal coupling, and relates to the technical field of photovoltaic power stations and thermoelectric power generation, the energy efficiency optimization type power station system comprises a photo-thermal fused salt storage tank hot tank, a photo-thermal fused salt storage tank cold tank and an inversion grid-connected device, and the photo-thermal fused salt storage tank hot tank and the photo-thermal fused salt storage tank cold tank are connected through a heat exchange assembly; fused salt is stored in both the photo-thermal fused salt storage tank hot tank and the photo-thermal fused salt storage tank cold tank, an N-type semiconductor module is mounted on the photo-thermal fused salt storage tank hot tank, a P-type semiconductor module is mounted on the photo-thermal fused salt storage tank cold tank, and both the N-type semiconductor module and the P-type semiconductor module are electrically connected with the inverter grid-connected device; the N-type semiconductor module and the P-type semiconductor module are introduced into the photo-thermal fused salt storage tank hot tank and the photo-thermal fused salt storage tank cold tank, and the thermoelectric power generation technology is combined with an existing photo-thermal power station structure, so that a traditional photo-thermal power generation system cannot be affected; and the primary frequency modulation response rate and response capability of the photo-thermal power station can be optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power stations and temperature difference power generation, and in particular to an energy efficiency optimized power station system based on temperature difference power generation-photothermal coupling. Background Art

[0002] Solar thermal power generation is a new type of low-carbon power generation technology. The internal heat storage system can achieve continuous and stable power generation throughout the day and can start and stop quickly, and is expected to become an important peak-shaving power source. Accordingly, the solar thermal power station collects solar energy and converts it into heat energy, which then drives the steam turbine to generate electricity. The core advantage of this process is that it can use the heat storage system to continue to provide a stable power supply during periods of insufficient sunlight or at night, thereby achieving 24-hour continuous power generation and having a strong peak-shaving capability.

[0003] However, the frequency regulation capability and response speed of the CSP system are still key factors affecting its widespread application. Especially in a frequency regulation process, the change in the unit output of the CSP power station mainly depends on the energy storage state of the front-end system. The performance of the heat storage system directly determines the response capability and rate of the unit when facing grid frequency fluctuations. In order to improve the frequency regulation response capability and peak regulation capability of the system, the traditional CSP power generation system relies on the thermal energy storage and release process, which is a relatively slow process, making it difficult for the system to quickly adjust the output in a short period of time and unable to meet the frequent changes in grid demand. As the requirements of the power system for fast frequency regulation response gradually increase, how to optimize the frequency regulation performance of the CSP power station is particularly important. Therefore, the present invention proposes an energy efficiency optimization power station system based on thermoelectric power generation-photothermal coupling to solve the problems existing in the prior art. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to propose an energy-efficiency optimized power station system based on thermoelectric power generation-photothermal coupling. This energy-efficiency optimized power station system based on thermoelectric power generation-photothermal coupling has the advantages of enhancing the primary frequency regulation and peak regulation capabilities of the solar thermal power station, and can solve the problems existing in the prior art.

[0005] To achieve the purpose of the present invention, the present invention is implemented through the following technical scheme: an energy efficiency optimized power station system based on temperature difference power generation-photothermal coupling, comprising a photothermal molten salt storage tank hot tank, a photothermal molten salt storage tank cold tank and an inverter grid-connected device, the photothermal molten salt storage tank hot tank and the photothermal molten salt storage tank cold tank are connected by a heat exchange component, and the photothermal molten salt storage tank hot tank and the photothermal molten salt storage tank cold tank both store molten salt, an N-type semiconductor module is installed on the photothermal molten salt storage tank hot tank, and a P-type semiconductor module is installed on the photothermal molten salt storage tank cold tank, the N-type semiconductor module and the P-type semiconductor module are both electrically connected to the inverter grid-connected device, the wiring lead-out end of the N-type semiconductor module is a negative electrode, and the wiring lead-out end of the P-type semiconductor module is a positive electrode, and the inverter grid-connected device is used to connect to the grid for power generation.

[0006] A further improvement is that the N-type semiconductor module includes several groups of N-type semiconductors, and the several groups of N-type semiconductors are evenly inserted into the hot tank of the photothermal molten salt storage tank.

[0007] A further improvement is that the P-type semiconductor module includes several groups of P-type semiconductors, and the several groups of P-type semiconductors are evenly inserted into the cold tank of the photothermal molten salt storage tank.

[0008] A further improvement is that: a plurality of groups of N-type semiconductors are equipped with parallel switches, and are connected to the N-type semiconductor outgoing busbars via the parallel switches.

[0009] A further improvement is that both the N-type semiconductor module and the P-type semiconductor module adopt a rod-shaped structure.

[0010] A further improvement is that the heat exchange component includes a molten salt pump and a heat exchanger, the input end and the output end of the molten salt pump are respectively connected to the hot tank of the photothermal molten salt storage tank and the heat exchanger, and the heat exchanger is connected to the cold tank of the photothermal molten salt storage tank.

[0011] A further improvement is that: a plurality of groups of the P-type semiconductors are connected in parallel via a P-type semiconductor outgoing busbar.

[0012] The beneficial effects of the present invention are:

[0013] (1) The present invention introduces N-type semiconductor modules and P-type semiconductor modules into the hot tank and cold tank of the molten salt storage tank, and combines the temperature difference power generation technology with the existing structure of the CSP power station, which will not cause adverse effects on the traditional CSP power generation system. As an additional function, the temperature difference power generation does not interfere with the operation of the traditional power generation method, and can further improve the performance of the traditional CSP power station while ensuring the stable operation of the traditional CSP power station.

[0014] (2) The present invention mainly relies on semiconductor materials and molten salt as the medium, does not involve complex mechanical movements and high-frequency replacement work, and therefore has low maintenance costs and high reliability. Especially in high temperature and high pressure environments, the temperature difference power generation system can work stably, reducing the long-term maintenance burden of the solar thermal power station system.

[0015] (3) In the present invention, the number of N-type semiconductors in parallel can be controlled to achieve rapid regulation of the grid frequency (primary frequency modulation). This flexible regulation method enables the CSP station to better provide power support when the grid load fluctuates and reduce dependence on traditional backup power sources. Therefore, during the peak regulation process, the temperature difference power generation system can provide additional power when the sunshine is insufficient or the load demand increases, so that the CSP station can smoothly transition, thereby optimizing the primary frequency regulation response rate and response capability of the CSP station and enhancing the peak regulation capability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of a solar thermal power station system of the present invention.

[0017] Among them: 1. Parallel switch; 2. N-type semiconductor module; 3. Hot tank of solar thermal molten salt storage tank; 4. Molten salt pump; 5. Heat exchanger; 6. Cold tank of solar thermal molten salt storage tank; 7. P-type semiconductor module; 8. Inverter grid-connected device. DETAILED DESCRIPTION

[0018] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0019] As the power system's requirements for fast frequency response gradually increase, traditional CSP plants have certain limitations in dealing with grid frequency fluctuations. The core advantage of CSP plants is that they can provide stable and continuous power output, but their frequency regulation performance is relatively weak, especially when dealing with rapid and frequent grid load changes, there are problems such as insufficient response speed and insufficient regulation capacity.

[0020] At present, the frequency regulation process of CSP power stations mainly relies on the conversion and release of heat energy in the heat storage system, which is a relatively slow process. Although CSP power stations have strong peak-shaving capabilities and can provide more electricity when solar energy is strong, and can also rely on the heat storage system to maintain power generation when the sunshine is insufficient, the existing system has poor flexibility and rapidity in frequency regulation response when facing rapid frequency fluctuations in the power grid. Especially in the case of frequent load fluctuations, the regulation speed and accuracy of traditional CSP power stations often cannot meet the requirements of the power grid for rapid frequency regulation.

[0021] For example, when the power system needs to increase or decrease the load quickly, the CSP power station usually relies on the temperature difference change of the molten salt heat storage system, and this process may take a long time to achieve the required power output regulation. Due to this long response time, when the grid load changes rapidly, it may not be able to provide sufficient power generation capacity in time, and may even cause fluctuations in the grid frequency, affecting the stability of the grid.

[0022] Therefore, it is particularly important to optimize the frequency regulation performance of CSP plants. Improving frequency regulation performance can not only enhance the peak-shaving capacity of CSP plants, but also ensure that when the grid load fluctuates or is unstable, it can respond quickly and accurately to grid demand and ensure the stable operation of the power system.

[0023] Therefore, according to Figure 1 As shown, this embodiment proposes an energy efficiency optimization power station system based on temperature difference power generation-photothermal coupling, including a photothermal molten salt storage tank hot tank 3, a photothermal molten salt storage tank cold tank 6 and an inverter grid-connected device 8. For the inverter grid-connected device 8, it mainly includes a DC-AC inverter, which is the core part of the inverter grid-connected device and is responsible for converting the direct current (DC) generated by the system into alternating current (AC). The inverter usually uses a semiconductor switching element (such as IGBT, insulated gate bipolar transistor) to control the conversion of current. Accordingly, the input end receives the direct current generated by the system, and the output end outputs alternating current. Further, the inverter grid-connected device 8 also includes other parts, such as a maximum power point tracking controller, a grid-connected protection device, etc. Since it belongs to the prior art, its specific structure will not be described in detail in this specification.

[0024] For this system, it introduces temperature difference power generation, and the overall working principle is as follows:

[0025] N-type semiconductor module 2, P-type semiconductor module 7, photothermal molten salt storage tank hot tank 3 and photothermal molten salt storage tank cold tank 6 constitute a large Peltier junction, in which the P-type semiconductor module 7 wiring lead-out end is the positive electrode of temperature difference power generation, and the N-type semiconductor module 2 wiring lead-out end is the negative electrode of temperature difference power generation, and finally the grid-connected power generation is generated through the inverter grid-connected device. In this process, the Peltier effect is the core principle of temperature difference power generation. When there is a temperature difference between the two ends of the N-type and P-type semiconductor materials, a voltage difference will be generated between the two ends. This voltage difference can drive current and thus be converted into electrical energy, so that the N-type semiconductor module 2 and the P-type semiconductor module 7 are respectively placed in the photothermal molten salt storage tank hot tank 3 and the photothermal molten salt storage tank cold tank 6, and the voltage difference is generated by the temperature difference between them. The molten salt temperature in the photothermal molten salt storage tank hot tank 3 is higher, and the molten salt temperature in the photothermal molten salt storage tank cold tank 6 is lower. This temperature difference provides an energy source for the Peltier effect. Then, the P-type semiconductor module 7 is responsible for receiving the output of the current and transmitting it to the inverter grid-connected device 8. The N-type semiconductor module 2 is responsible for forming a closed circuit with the P-type semiconductor module 7. The current flows through this path. Due to the different electrical properties of the N-type semiconductor module 2 and the P-type semiconductor module 7, the flow of current between them will form a voltage difference, thereby providing a stable current output.

[0026] Molten salt is stored in both the hot tank 3 of the photothermal molten salt storage tank and the cold tank 6 of the photothermal molten salt storage tank. At the same time, the hot tank 3 of the photothermal molten salt storage tank and the cold tank 6 of the photothermal molten salt storage tank are connected by a heat exchange component, and the heat exchange component includes a molten salt pump 4 and a heat exchanger 5. The input end and the output end of the molten salt pump 4 are respectively connected to the hot tank 3 of the photothermal molten salt storage tank and the heat exchanger 5, and the heat exchanger 5 is connected to the cold tank 6 of the photothermal molten salt storage tank. Specifically, the hot tank 3 of the photothermal molten salt storage tank stores high-temperature molten salt, which provides a heat source for the N-type semiconductor module 2, and the cold tank 6 of the photothermal molten salt storage tank stores a lower temperature molten salt, which provides a low-temperature source for the P-type semiconductor module 7. The molten salt pump 4 and the heat exchanger 5 promote the flow of molten salt between the hot tank and the cold tank and realize the exchange of heat. Therefore, the setting of the heat exchanger 5 allows the hot salt in the hot tank and the cold salt in the cold tank to maintain a temperature difference through the heat exchange process, thereby improving the efficiency of the Peltier effect. Thus, the hot tank 3 of the solar thermal molten salt storage tank and the cold tank 6 of the solar thermal molten salt storage tank are connected through the molten salt pump 4 and the heat exchanger 5, and the temperature difference is continuously maintained through the heat exchange process, which provides a stable heat source and cold source for temperature difference power generation. Through this heat transfer and maintenance of temperature difference, the system can operate efficiently and convert thermal energy into electrical energy, thereby improving the frequency regulation and peak regulation capabilities of the solar thermal power station and enhancing the overall efficiency of the system.

[0027] An N-type semiconductor module 2 is installed on the thermal tank 3 of the photothermal molten salt storage tank. The N-type semiconductor module 2 includes several groups of N-type semiconductors. Several groups of N-type semiconductors are evenly inserted into the thermal tank 3 of the photothermal molten salt storage tank. Parallel switches 1 are installed on the several groups of N-type semiconductors, and are connected to the N-type semiconductor outgoing busbar through the parallel switch 1. The function of the parallel switch 1 is usually to control the flow of current in the circuit, so that the N-type semiconductor can be disconnected from other parts independently or when necessary. In the frequency modulation process, some N-type semiconductors may be selectively connected or disconnected according to the needs of the power grid to change the output power of the system or adjust the load capacity of the system.

[0028] A P-type semiconductor module 7 is installed on the cold tank 6 of the photothermal molten salt storage tank. The P-type semiconductor module 7 includes several groups of P-type semiconductors. Several groups of P-type semiconductors are evenly inserted into the cold tank 6 of the photothermal molten salt storage tank. Several groups of P-type semiconductors are connected in parallel through the P-type semiconductor output busbar. In the design of the P-type semiconductor, multiple P-type semiconductors are connected in parallel through the P-type semiconductor output busbar. Unlike the parallel switch 1 design of the N-type semiconductor, the connection of the P-type semiconductor module 7 is constant, and there is usually no separate switch to control the opening or closing of each P-type semiconductor.

[0029] Both the N-type semiconductor module 2 and the P-type semiconductor module 7 adopt a rod-shaped structure, that is, both the N-type semiconductor and the P-type semiconductor are rod-shaped, and the rod-shaped structure has a large surface area, which can effectively exchange heat with the hot salt and cold salt in the solar thermal molten salt storage tank. Therefore, by increasing the contact area, the heat conduction efficiency is improved, ensuring that the temperature difference is maintained at a large level at both ends of the semiconductor module, thereby optimizing the Peltier effect and improving the power generation efficiency.

[0030] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the framework and scope of application of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An energy efficiency optimization power station system based on temperature difference power generation and photothermal coupling, comprising a photothermal molten salt storage tank hot tank (3), a photothermal molten salt storage tank cold tank (6) and an inverter grid-connected device (8), characterized in that: The hot tank (3) of the photothermal molten salt storage tank and the cold tank (6) of the photothermal molten salt storage tank are connected via a heat exchange component, and both the hot tank (3) of the photothermal molten salt storage tank and the cold tank (6) of the photothermal molten salt storage tank store molten salt ...

2. According to claim 1, an energy efficiency optimized power station system based on temperature difference power generation and photothermal coupling is characterized by: The N-type semiconductor module (2) comprises a plurality of groups of N-type semiconductors, and the plurality of groups of N-type semiconductors are uniformly inserted into the photothermal molten salt storage tank (3).

3. The energy efficiency optimized power station system based on temperature difference power generation and photothermal coupling according to claim 1 is characterized by: The P-type semiconductor module (7) comprises a plurality of groups of P-type semiconductors, and the plurality of groups of P-type semiconductors are uniformly inserted into the photothermal molten salt storage tank cold tank (6).

4. The energy efficiency optimization power station system based on temperature difference power generation and photothermal coupling according to claim 2 is characterized by: A parallel switch (1) is installed on each of the groups of N-type semiconductors, and is connected to the N-type semiconductor outgoing busbar via the parallel switch (1).

5. The energy efficiency optimized power station system based on temperature difference power generation and photothermal coupling according to claim 1 is characterized by: The N-type semiconductor module (2) and the P-type semiconductor module (7) both adopt a rod-shaped structure.

6. The energy efficiency optimized power station system based on temperature difference power generation and photothermal coupling according to claim 1 is characterized by: The heat exchange component comprises a molten salt pump (4) and a heat exchanger (5), wherein the input end and the output end of the molten salt pump (4) are respectively connected to a hot tank (3) of a photothermal molten salt storage tank and the heat exchanger (5), and the heat exchanger (5) is connected to a cold tank (6) of a photothermal molten salt storage tank.

7. The energy efficiency optimized power station system based on temperature difference power generation and photothermal coupling according to claim 1 is characterized by: Several groups of the P-type semiconductors are connected in parallel via a P-type semiconductor output busbar.

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