A photo-thermal power generation system

Abstract

The application discloses a kind of photo-thermal power generation systems, including real-time tracking sunlight and the light reflection of sunlight is gathered by condensing device, part is set in the circulating oil circuit of the reflection gathering area of condensing device, heat conducting medium in circulating oil circuit is heated using sunlight;For heat exchange of heat conducting medium and water in steam loop Heat exchanger, the conversion of heat energy to electric energy is realized by steam turbine of high-temperature high-pressure water vapor to drive generator set;Wherein, condensing device includes condensing lens, condensing lens has the composite reflecting mirror surface layer of high reflectivity.The application is provided with the composite reflecting mirror surface layer of high reflectivity, the reflectivity of sunlight is improved by using four layers of metal plating layer in reflecting mirror surface layer, and the condensing device has good heat dissipation capacity, the condensing device is not easy to deform and crack in long-term use, and the reflectivity and service life of the condensing device are improved.

Description

Technical Field

[0001] This invention relates to the field of concentrated solar power generation technology, and more particularly to a concentrated solar power generation system. Background Technology

[0002] Currently, the main methods of utilizing solar energy are photovoltaic (PV) power generation devices and photovoltaic cell devices. PV power generation devices are costly to manufacture and cause significant pollution. The manufacturing process requires the use of toxic materials such as arsenic, causing a series of pollution problems to the environment and water bodies. Individual PV panels have low voltage, requiring complex series and parallel connections to achieve high output voltage. Careful maintenance of the PV panel tabs is necessary during use. Furthermore, the photoelectric conversion efficiency of PV panels gradually decreases over time. PV panels need to be used under a tightly sealed protective gas environment to prevent contamination from oxygen and dust. As oxidation deepens on the PV surface, the photoelectric conversion efficiency gradually decreases. The lifespan of a PV panel is generally 7-8 years. A brand-new PV panel typically has a photoelectric conversion efficiency of around 45%, but by the 7th year, the efficiency drops to around 25%, indicating a severe decline in power generation efficiency, while the heat generated by the PV panel itself also increases. Thin-film photovoltaic cells are currently not a mature technology and have not yet reached the stage of mass production.

[0003] In the current era of rapid development of new energy sources, how to collect and utilize natural energy is a major theme in new energy research. Patent document CN111379678B discloses an invention providing a solar thermal power generation system, comprising: at least one Stirling engine 5, a molten salt tank 6, a mirror field 10, molten salt liquid, and multiple conduits; the molten salt tank 6 is connected to the mirror field 10 via the multiple conduits; the hot end of the Stirling engine 5 is inserted into the molten salt tank 6; after absorbing solar heat energy through the mirror field 10, the molten salt is stored in the molten salt tank 6 via the multiple conduits; the molten salt liquid in the molten salt tank 6 has a first position and a second position; the first position is higher than the second position; when the molten salt liquid is at the first position, the Stirling engine 5 operates; when the molten salt liquid is at the second position, the Stirling engine 5 stops operating.

[0004] It utilizes a Stirling engine as the prime mover, significantly reducing the need for auxiliary equipment in the solar thermal power generation system, and its energy conversion efficiency is higher than that of using a steam turbine, thus improving the efficiency of solar energy utilization. However, there are also some drawbacks: 1. The concentrator is one of the core components of the solar thermal power generation system, affecting the efficiency of sunlight reflection utilization; no improvements have been observed in the concentrator. 2. It uses molten salt as the heat transfer medium, but molten salt itself has inherent defects, such as low thermal conductivity, low specific heat capacity, corrosiveness, and liquid leakage during phase change. These drawbacks require the corresponding thermal storage device materials to have high corrosion resistance, increasing the equipment manufacturing cost.

[0005] Patent document CN108869214A discloses a solar thermal power generation system, including: an air compressor, a solar thermal storage device, a solar thermal-air heat exchanger, an air expander, and a generator; the air compressor, air expander, and generator are coaxially connected; the heat medium pipeline of the solar thermal-air heat exchanger is connected to the heat storage medium circulation pipeline of the solar thermal storage device; the inlet of the cold medium pipeline of the solar thermal-air heat exchanger is connected to the exhaust port of the air compressor, and the outlet of the cold medium pipeline is connected to the inlet of the air expander; the air is pressurized by the air compressor and then further passes to the solar thermal-air heat exchanger for heat exchange, thereby forming high-temperature and high-pressure air; the high-temperature and high-pressure air drives the air expander to operate, which in turn drives the coaxial air compressor to operate, and simultaneously drives the coaxial generator to generate electricity.

[0006] This invention employs the Brayton cycle with air as the medium, which can greatly improve power generation efficiency. However, it also has the following drawbacks: 1. No improvement has been made to the concentrating device, which can easily lead to low light reflection utilization and low photothermal conversion efficiency; 2. Although the heat transfer medium is gas, the thermal conductivity of gas is often lower than that of liquid, and the requirements for device sealing and pressure holding are higher, which can easily increase the manufacturing cost of the device. Summary of the Invention

[0007] The purpose of this invention is to provide a safe and environmentally friendly solar thermal power generation system. It adopts a high-reflectivity concentrator with a multi-layer metal coating on the reflector surface to improve light reflectivity, enhance the heat dissipation capacity of the concentrator, strengthen the structural strength of the concentrator, and prevent the concentrator from deteriorating over a long period of use. At the same time, it improves the heat-conducting medium and increases the photoelectric conversion efficiency of the solar thermal power generation system.

[0008] The objective of this invention can be achieved through the following technical solution: a solar thermal power generation system, including a concentrating device that tracks sunlight in real time and reflects and concentrates sunlight;

[0009] The circulating oil circuit is partially located in the reflection and focusing area of ​​the concentrator, using sunlight to heat the heat-conducting medium in the circulating oil circuit.

[0010] A heat exchanger is used to exchange heat between a heat transfer medium and water in a steam circuit, and to convert water into high-temperature, high-pressure steam.

[0011] Generator sets use high-temperature, high-pressure steam to drive turbines and convert thermal energy into electrical energy.

[0012] The light-concentrating device includes a condenser lens, which has a composite reflective mirror surface layer with high reflectivity.

[0013] Furthermore, the focusing mirror also includes a base layer, the reflective mirror layer is disposed on the sun-facing surface of the base layer, and the composite reflective mirror layer has multiple layers of metal coating.

[0014] Furthermore, the reflective mirror layer is provided with a first copper plating layer, a second nickel plating layer, a third aluminum plating layer and a fourth silver plating layer from bottom to top.

[0015] Furthermore: the base layer material is glass fiber, and the value ranges for each layer of the base layer and the reflective mirror layer are as follows:

[0016] The base layer has a thickness of 3mm-5mm;

[0017] The first copper plating layer has a thickness of 0.35μm-0.4μm;

[0018] The second nickel plating layer has a thickness of 0.3μm-0.35μm;

[0019] The third aluminum plating layer has a thickness of 0.2mm-0.6mm;

[0020] The fourth silver plating layer has a thickness of 0.3μm-0.38μm.

[0021] Furthermore, the surface of the fourth silver plating layer is covered with a 0.6mm-0.65mm thick enamel layer, which is used to protect the reflective mirror layer.

[0022] Furthermore, the heat-conducting medium is diesel oil.

[0023] Furthermore: the material of some circulating oil circuits located in the reflection and focusing area of ​​the concentrator is copper or stainless steel; the material of some circulating oil circuits located in the heat exchanger is copper or stainless steel.

[0024] The beneficial effects of this invention are:

[0025] 1. The solar thermal power generation device provided in this invention is safe and reliable, small in size, easy to install and use, and convenient to maintain. The generated electricity can be used directly or directly connected to the power grid for output. (6m³) 2 The concentrator lens can generate 126-142 kWh of electricity per day, making it a safe and environmentally friendly solar thermal power generation device.

[0026] 2. This invention improves the reflectivity of sunlight by setting a composite reflective mirror layer with high reflectivity, while also giving the concentrator better heat dissipation capabilities. The concentrator is less prone to deformation and cracking during long-term use, thus improving the reflectivity and service life of the concentrator.

[0027] 3. The reflective mirror layer employs a four-layer metal plating. A copper plating layer connects the entire mirror to the fiberglass layer, providing excellent heat dissipation and ensuring consistency in the mirror's structure and curvature. A nickel plating layer buffers deformation, protecting the mirror from heat-induced cracking or delamination, and ensuring consistent curvature across the surface layer. An aluminum plating layer maintains uniform surface temperature, ensuring efficient light reflection. A silver plating layer ensures sufficient reflectivity. Through this layered metal plating, the reflective mirror layer's light reflectivity is enhanced while maintaining the strength of the condenser lens, extending its lifespan, and providing optimal reflective curvature.

[0028] 4. Using liquid diesel as the heat transfer medium, compared with other liquid heat transfer materials such as water and gasoline, diesel has a relatively small heat capacity of 3.99 KJ / kg / K. In addition, diesel has a fast temperature rise, a relatively large thermal conductivity, and low material cost, making it a suitable heat transfer material that can improve photothermal conversion efficiency while reducing product cost. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a solar thermal power generation system according to the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of the light-concentrating device of the present invention;

[0031] Figure 3 This is a schematic diagram of the layered structure of the condenser lens of the present invention;

[0032] Figure 4 This is a schematic diagram of how the concentrator lens of the present invention focuses sunlight to heat the circulating oil circuit.

[0033] 100. Concentrating device; 110. Concentrating mirror; 111. Reflecting mirror surface layer; 111a. First copper plating layer; 111b. Second nickel plating layer; 111c. Third aluminum plating layer; 111d. Fourth silver plating layer; 112. Base layer; 113. Enameled glass layer; 120. Mounting bracket; 130. Solar tracking device; 200. Circulating oil circuit; 210. Oil circuit circulation drive device; 300. Heat exchanger; 400. Steam circuit; 500. Generator set; 600. Rectifier and voltage regulator device; 700. Grid connection circuit. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0035] like Figure 1-4 As shown, this invention discloses a concentrated solar power (CSP) system, comprising:

[0036] The concentrator 100 tracks sunlight in real time and reflects and concentrates sunlight.

[0037] The circulating oil circuit 200, part of which is located in the reflection and focusing area of ​​the concentrating device 100, uses sunlight to heat the heat-conducting medium in the circulating oil circuit 200.

[0038] Heat exchanger 300 is used for heat exchange between the heat transfer medium and water in steam circuit 400, and to convert water into high-temperature and high-pressure steam;

[0039] The generator set 500 uses high-temperature, high-pressure steam to drive a steam turbine to convert thermal energy into electrical energy;

[0040] The focusing device 100 includes a focusing mirror 110, which has a high-reflectivity composite reflective mirror layer 111.

[0041] Concentrating device 100, such as Figure 2 As shown, the focusing device 100 mainly consists of the following components:

[0042] Mounting bracket 120 is used to fix the solar collection device to the ground to ensure the stable operation of the entire device.

[0043] The solar tracking device 130 is connected to the mounting bracket 120. It adjusts the angle of the mirror concentrator 100 in real time according to the direct angle of sunlight, so as to keep the concentrator 110 receiving the maximum direct angle of sunlight at all times, thereby maximizing the conversion and utilization of light energy.

[0044] It also includes a partial circulation oil circuit 200 located in the reflection gathering area. The partial circulation oil circuit 200 in the reflection gathering area is fixed in relative position with the condenser lens 110 and is adjusted in real time by the solar tracking device 130 along with the condenser lens 110.

[0045] like Figure 4 As shown, this embodiment uses a U-shaped trough solar concentrator 110 to reflect and collect sunlight. Driven by the solar tracking device 130, the concentrator 110 automatically tracks the change of the angle of sunlight to maximize the direct angle of sunlight in real time, thereby maximizing the collection and conversion of solar energy. After being reflected by the U-shaped trough solar concentrator 110, sunlight forms a linear reflection and concentration area. Part of the circulating oil circuit 200 is set in the reflection and concentration area, and the heat-conducting medium is heated by the sunlight irradiation of the reflection and concentration area.

[0046] like Figure 3As shown, the condenser lens 110 consists of five layers. The base layer 112 is made of fiberglass with a thickness of 3mm-5mm. The base layer 112 is supported and fixed by a steel structure, which supports the entire reflector surface layer 111 structure.

[0047] A reflective mirror layer 111 is provided on the side of the base layer 112 facing the sun. The reflective mirror layer 111 adopts a layered metal plating structure. The reflective mirror layer 111 can be electroplated or chemically plated to make the reflective mirror layer 111 tightly bonded to the glass fiber structure layer to form a whole.

[0048] The reflective mirror layer 111 is provided with a first copper plating layer 111a, a second nickel plating layer 111b, a third aluminum plating layer 111c, and a fourth silver plating layer 111d from bottom to top, starting from the base layer 112. The first copper plating layer 111a is connected to the base layer 112 through a plating process, and the other layers are connected to each other through a plating process. The fourth silver plating layer 111d is located on the outermost side closest to the sun.

[0049] The first copper plating layer 111a has a thickness of 0.35μm-0.4μm. The first copper plating layer 111a serves to connect the entire reflective mirror layer 111 with the glass fiber structure layer. At the same time, it plays a role in heat dissipation of the reflective mirror layer 111 during operation, ensuring the consistency of the structure and curvature of the reflective mirror layer 111. It will not deform due to heat, reducing the overall reflectivity of the reflective mirror layer 111, and preventing damage to the reflective mirror layer 111 due to thermal expansion and contraction.

[0050] The second nickel plating layer 111b has a thickness of 0.3μm-0.35μm. During operation, the second nickel plating layer 111b mainly diffuses and conducts temperature to ensure the overall curvature of the condenser lens 110 is consistent. At the same time, it plays a buffering role against deformation, protects the mirror layer 111 from heat cracking or interlayer separation under high temperature, and ensures the overall curvature of the surface layer is consistent.

[0051] The third aluminum plating layer 111c has a thickness of 0.2mm-0.6mm. The third aluminum plating layer 111c supports the smoothness and uniformity of the mirror surface, while effectively achieving heat diffusion and ensuring a uniform surface temperature.

[0052] The fourth silver plating layer 111d has a plating thickness of 0.3μm-0.38μm. The fourth silver plating layer 111d is located on the outermost side of the reflective mirror layer 111 to ensure that the mirror layer 111 has sufficient reflectivity.

[0053] The outer side of the overall reflective mirror layer 111 is protected by an optical enamel layer 113. The thickness of the enamel layer 113 is 0.6mm-0.65mm. The enamel layer 113 serves to isolate dust, prevent corrosion and oxidation of the reflective layer, and ensure that the reflective mirror layer 111 is intact and not damaged by the outside world.

[0054] The composite reflective mirror layer 111 achieves a reflection efficiency of over 99.2%, effectively collecting solar energy and significantly improving the utilization rate of reflected sunlight.

[0055] Diesel fuel is used as the heat transfer medium in the circulating oil circuit 200. A portion of the circulating oil circuit 200 is located in the reflection concentration area, and the diesel fuel in the circulating oil circuit 200 is directly heated by focused sunlight, converting light energy into heat energy of the oil circuit.

[0056] Compared to other liquid materials such as water and gasoline, diesel has a relatively small heat capacity of 3.99 kJ / (kg·K). In addition, diesel has a fast temperature rise, a relatively large thermal conductivity, is easy to obtain, and has a low cost, making it a suitable heat transfer material.

[0057] Other liquids can also be used as the heat transfer medium, such as heavy smelting oil, water, or a 1:1 mixture of ethylene glycol and water; gases such as N2 or other inert gases can also be used.

[0058] The circulating oil circuit 200 located in the reflection focusing area of ​​the concentrating device 100 is made of stainless steel or copper, which can give the heated part of the circulating oil circuit 200 good thermal conductivity, which can quickly raise the temperature of the heat transfer medium. At the same time, stainless steel or copper also has sufficient strength to protect the circulating oil circuit 200 located in the reflection focusing area of ​​the concentrating device 100 from deformation.

[0059] The portion of the circulating oil passage 200 located within the heat exchanger 300 should also be made of stainless steel or copper. This can give the circulating oil passage 200 in the heat exchange section good thermal conductivity. The circulating oil passage 200 in the heat exchange section can be modified according to the structure of the heat exchanger 300, for example, by making it mesh or plate-shaped. These modifications are widely used in existing technologies and will not be described in detail here. After the modifications, the circulating oil passage 200 can achieve efficient heat exchange.

[0060] Other parts of the circulating oil circuit 200 can also be made of stainless steel or copper, or other metal or plastic pipes with lower cost, while ensuring proper insulation to prevent heat loss of the heat transfer medium.

[0061] The heat exchanger 300 exchanges heat between diesel or other heat-conducting media and water in the steam circuit 400, converting the water into high-temperature, high-pressure steam. By reflecting and focusing sunlight, it heats the diesel in the circulation pipe 200, converting solar energy into the heat energy of the diesel. The diesel reaches a maximum temperature of over 360°C. Heat exchange occurs between the hot diesel and the water in the steam circuit 400, transferring the heat energy of the high-temperature diesel to the water in the steam circuit 400 in a timely manner.

[0062] High-temperature diesel fuel is driven by an oil circuit circulation drive device 210. The oil circuit circulation drive device 210 uses a motor to achieve closed-loop circulation of high-temperature hot diesel fuel. The motor can be a small 300W motor to realize the circulation of diesel fuel in the oil circuit 200, realize the real-time heat transfer between diesel fuel and water in the heat exchanger 300, realize the cooling of hot oil, and realize the generation and heating of water vapor in the closed steam circuit 400. The water is heated and vaporized, which can continuously generate high-temperature and high-pressure water vapor.

[0063] Through heat exchange, the steam temperature can reach 280-360℃ and the steam pressure can reach 8.3MPa-9MPa. The high temperature and high pressure steam directly drives the steam turbine in generator set 500. The steam turbine can be a 3000r / min steam turbine unit. The generator in generator set 500 can be a single-cylinder single-shaft condensing steam turbine generator with a power of 20KW.

[0064] Actual measurements showed that using this device, a 6m... 2 The condenser lens 110 can generate 126-142 kWh of electricity per day under average daily illuminance.

[0065] The generated electrical energy is fed into the grid-connected circuit 700 through the rectifier and voltage regulator 600 to achieve grid connection.

[0066] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0067] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0068] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0069] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

Claims

1. A concentrated solar power generation system, characterized in that: include A light-concentrating device (100) tracks sunlight in real time and reflects and concentrates sunlight; The circulating oil circuit (200) is partially located in the reflection and focusing area of ​​the concentrating device (100), and uses sunlight to heat the heat-conducting medium in the circulating oil circuit (200). A heat exchanger (300) is used for heat exchange between the heat transfer medium and water in the steam circuit (400) and to convert the water into high-temperature and high-pressure steam. The generator set (500) uses high-temperature and high-pressure steam to drive a steam turbine to convert thermal energy into electrical energy; The light-concentrating device (100) includes a light-concentrating mirror (110), which has a composite reflective mirror layer (111) with high reflectivity. The condenser lens (110) also includes a base layer (112), and the composite reflective mirror layer (111) is disposed on the sun-facing surface of the base layer (112), and the composite reflective mirror layer (111) has multiple layers of metal coating; The composite reflective mirror layer (111) is provided with a first copper plating layer (111a), a second nickel plating layer (111b), a third aluminum plating layer (111c) and a fourth silver plating layer (111d) from bottom to top. The base layer (112) is made of glass fiber, and the value ranges of each layer of the base layer (112) and the composite reflective mirror layer (111) are as follows: The base layer (112) has a thickness of 3mm-5mm; The first copper plating layer (111a) has a thickness of 0.35μm-0.4μm; The second nickel plating layer (111b) has a thickness of 0.3μm-0.35μm; The third aluminum plating layer (111c) has a thickness of 0.2mm-0.6mm; The fourth silver plating layer (111d) has a thickness of 0.3μm-0.38μm.

2. A solar thermal power generation system according to claim 1, characterized in that: The surface of the fourth silver plating layer (111d) is covered with a 0.6mm-0.65mm thick enamel layer (113), which is used to protect the composite reflective mirror layer (111).

3. A solar thermal power generation system according to claim 1, characterized in that: The heat transfer medium is diesel fuel.

4. A solar thermal power generation system according to claim 1, characterized in that: The material of the part of the circulating oil circuit (200) located in the reflection and focusing area of ​​the focusing device (100) is copper or stainless steel; The material of the part of the circulating oil circuit (200) located in the heat exchanger (300) is copper or stainless steel.

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