Tower solar receiver system integrated with thermionic power generating windows and method of operation thereof

Abstract

The application relates to a tower type solar receiving system integrated with a thermionic power generation window and a running method thereof, which comprises a heliostat field, a tower type solar receiver, a thermionic power generation light transmission window arranged at an incident light port of the tower type solar receiver, a solar heat absorption unit located in the tower type solar receiver, an external circuit connected with the thermionic power generation light transmission window, a running control unit, wherein the heliostat field is used for reflecting and focusing sunlight to the thermionic power generation light transmission window, the thermionic power generation light transmission window selectively absorbs part of photons in the incident concentrated sunlight and outputs electric energy through the external circuit, the remaining sunlight spectrum which is not absorbed or reflected transmits through the thermionic power generation light transmission window and enters the tower type solar receiver, and is absorbed by the solar heat absorption unit; the passive light transmission window of the traditional tower type solar receiver is converted into an active power generation window in the application, so that the window simultaneously has the functions of light transmission, power generation and spectrum energy flow regulation.

Description

Technical Field

[0001] This invention belongs to the fields of tower-type concentrated solar power generation, solar receiver, solar particle heat absorption and storage, solar thermal power generation and thermoelectric power generation, specifically involving a tower-type solar receiver system with an integrated thermoelectric power generation window and its operation method. Background Technology

[0002] Tower-type concentrated solar power (CSP) systems typically utilize heliostats to reflect and focus sunlight onto a receiver at the top of the tower. The receiver converts the concentrated solar energy into high-temperature thermal energy, which is then used for power generation via a thermal storage system and a heat-to-work conversion system. Tower solar receivers can utilize molten salt, air, solid particles, thermochemical reaction media, or other heat-absorbing media. Among these, solid particle receivers, with their potential for high-temperature operation and integrated thermal storage advantages, represent one of the important development directions for next-generation tower solar thermal power generation.

[0003] In some tower receivers, especially closed receivers, cavity receivers, pressurized receivers, particle receivers, or receivers that require controlled internal atmosphere, a light-transmitting window is required at the incident light port. Traditional light-transmitting windows mainly serve to transmit concentrated sunlight, isolate the external environment, and maintain the internal operating conditions of the receiver. They do not have power generation capabilities themselves, and it is difficult to actively regulate the incident solar spectrum energy flow.

[0004] On the other hand, tower-type concentrating solar receivers typically face challenges such as high heat flux density, non-uniform light spots, window thermal stress, optical loss, dust contamination, and high-temperature material stability. If the light-transmitting window can be designed to be a thermionic power generation window, then a portion of high-energy photons can be selectively utilized for power generation before sunlight enters the receiver, while allowing the remaining solar spectrum to continue passing through and heating the internal heat-absorbing medium of the receiver. This not only expands the energy utilization methods of tower solar systems but also enables spectral segmentation between front-end electrical output and back-end high-temperature thermal energy acquisition.

[0005] Therefore, it is necessary to propose a tower solar energy receiving system with an integrated thermionic power generation window and its operation method, so that the receiver inlet window can be transformed from a passive light-transmitting component into an active solar energy conversion component with functions of light transmission, power generation and spectral energy flow regulation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a tower solar energy receiving system with an integrated thermionic power generation window; The present invention also provides an operation method for a tower solar energy receiving system with an integrated thermionic power generation window; The present invention integrates a thermionic power generation device into the incident light window of a tower-type concentrated solar power receiver. Before the concentrated sunlight enters the receiver, some photons are absorbed by the power generation window and used for power output. The remaining solar spectrum passes through the power generation window and enters the receiver for high-temperature heat energy acquisition. This realizes the spectral classification utilization, power generation and heat absorption synergy, and energy flow regulation in the tower-type concentrated solar power system.

[0007] The technical solution of this invention is as follows: A tower solar receiver system with an integrated thermionic power generation window includes: Heliostat field; Tower solar receiver; Thermionic power generation light-transmitting window is provided at the light entrance of the tower solar receiver; The solar heat absorption unit is located inside the tower-type solar receiver; External circuitry connected to the thermionic power generation light-transmitting window; Operation control unit; The heliostat field is used to reflect and focus sunlight onto the thermionic power generation light-transmitting window. The thermionic power generation light-transmitting window selectively absorbs some photons in the incident concentrated sunlight and outputs electrical energy through an external circuit. The remaining solar spectrum that is not absorbed or reflected passes through the thermionic power generation light-transmitting window and enters the tower solar receiver, where it is absorbed by the solar heat absorption unit. The external circuit and operation control unit are used to coordinate and adjust the power output of the thermoelectric power generation window and the solar energy utilization process transmitted into the tower solar receiver according to solar irradiance conditions, the operating status of the thermoelectric power generation window, the heat absorption status of the tower solar receiver, and the heat storage requirements, so as to keep the thermoelectric power generation window and the tower solar receiver within a preset operating range.

[0008] According to a preferred embodiment of the present invention, the tower solar receiver is a tube bundle heat absorption structure, employing an integrated light-transmitting thermoelectric power generation heat absorption tube structure; the tower solar receiver includes a medium distribution component, a medium collection component, and multiple light-transmitting thermoelectric power generation heat absorption tubes disposed between the medium distribution component and the medium collection component; the medium distribution component has a low-temperature medium inlet, the medium collection component has a high-temperature medium outlet, and the inlet end of each light-transmitting thermoelectric power generation heat absorption tube is connected to the medium distribution component, and the outlet end is connected to the medium collection component; wherein, the medium distribution component is a particle distribution tank, an inlet header, a distribution pipeline, or a distribution cavity; the medium collection component is a particle collection tank, an outlet header, a manifold, or a collection cavity.

[0009] A medium flow channel is formed within the light-transmitting thermoelectric power generation absorber tube. The heat-absorbing medium within the medium flow channel includes one or more of the following: solid particles, molten salt, gas, heat transfer oil, water, water vapor, liquid metal, or mixtures thereof. Multiple light-transmitting thermoelectric power generation absorber tubes are arranged at intervals along the medium distribution assembly, forming a tube bundle-type heat absorption structure. The low-temperature heat-absorbing medium enters the medium distribution assembly through the low-temperature medium inlet, is distributed to each light-transmitting thermoelectric power generation absorber tube by the medium distribution assembly, absorbs heat from transmitted solar energy or heat transferred from the tube wall, enters the medium collection assembly, and is discharged from the high-temperature medium outlet.

[0010] When the heat-absorbing medium is solid particles, the solid particles can flow downward along the light-transmitting thermoelectric power generation heat-absorbing tube under the action of gravity, forming a free-fall particle flow, a hindered free-fall particle flow, a moving bed particle flow, or other particle flow forms; when the heat-absorbing medium is molten salt, gas, heat transfer oil, water, water vapor, or liquid metal, the heat-absorbing medium can flow along the light-transmitting thermoelectric power generation heat-absorbing tube under the action of pumping, pressure difference, natural circulation, or gravity.

[0011] More preferably, the medium flow channel of the light-transmitting thermoelectric power generation heat absorber tube is provided with one or more of the following: a blocking structure, a guiding structure, a turbulence structure, a heat exchange enhancement structure, or a porous medium structure, to adjust the flow path, residence time, mixing state, or heat exchange area of ​​the heat absorber medium. The blocking structure, guiding structure, turbulence structure, heat exchange enhancement structure, or porous medium structure includes one or more of the following: baffles, deflectors, perforated plates, grids, guide vanes, ribs, packing materials, wire mesh, honeycomb structures, foamed metal, or porous ceramics.

[0012] According to a preferred embodiment of the present invention, the operation control unit further includes a parameter detection component, which is connected to an external circuit and a corresponding actuator; the parameter detection component is used to detect at least one of the following parameters: input light intensity of the heliostat field, light spot distribution at the entrance of the tower solar receiver, temperature of the thermionic power generation light transmission window, output voltage of the thermionic power generation light transmission window, output current of the thermionic power generation light transmission window, transmitted light intensity, outlet temperature of the heat absorption medium, or heat storage state. The operation control unit generates control commands based on the detection results and sends the control commands to at least one of the following: electrical load adjustment module, heat-absorbing medium conveying device, particle conveying device, or heliostat field control device, in order to adjust the electrical load of the power generation window, the flow rate of the heat-absorbing medium, the particle circulation rate, or the heliostat field aiming strategy. The adjustment of the heat-absorbing medium flow rate or particle circulation rate is used to change the absorption capacity of the tower solar receiver for transmitted solar energy and the outlet temperature of the heat-absorbing medium; the adjustment of the heliostat field aiming strategy is used to change the incident light intensity or spot distribution at the thermionic power generation transmission window and the inlet of the tower solar receiver.

[0013] More preferably, the solar heat absorption unit is at least one of a sensible heat absorption unit, a phase change heat absorption unit, or a thermochemical reaction unit.

[0014] According to a preferred embodiment of the present invention, the solar heat absorption unit adopts a cavity-type solar heat absorption structure, which includes a receiver shell, a heat absorption cavity, and a heat absorption medium flow zone disposed within the heat absorption cavity; the thermionic power generation light transmission window is disposed at the light inlet of the receiver shell and constitutes the incident window of the heat absorption cavity; concentrated solar radiation first irradiates the thermionic power generation light transmission window, wherein a portion of the solar radiation is absorbed by the thermionic power generation light transmission window and used for thermionic power generation, and the unabsorbed solar radiation passes through the thermionic power generation light transmission window and enters the heat absorption cavity, where it is absorbed and utilized by the heat absorption medium within the heat absorption cavity.

[0015] More preferably, the heat-absorbing medium is solid particles, and the cavity-type solar heat-absorbing structure is a cavity-type solid particle heat-absorbing structure, including a cold particle inlet hopper, a particle heat-absorbing zone, and a hot particle collection hopper; the cold particle inlet hopper is located at the upper part of the receiver housing, and the hot particle collection hopper is located at the lower part of the receiver housing, forming a particle flow channel between the cold particle inlet hopper and the hot particle collection hopper. After entering the cold particle inlet hopper from the cold particle supply device, the solid particles enter the particle heat-absorbing zone and absorb solar radiation entering the heat-absorbing cavity. The heat-absorbing solid particles fall into the hot particle collection hopper and are then transported by the hot particle collection hopper to the subsequent particle utilization device.

[0016] Further preferably, the flow pattern of solid particles within the particle heat absorption zone includes one or more of the following: free-fall particle curtain, obstructed free-fall particle flow, staged falling particle flow, inclined plate sliding particle flow, moving bed particle flow, fluidized particle flow, or particle flow within a porous medium. The particle heat absorption zone is equipped with blocking structures, guiding structures, dispersing structures, turbulence structures, inclined sliding structures, or porous medium structures to adjust the falling velocity, residence time, flow path, particle curtain thickness, or particle distribution uniformity of the solid particles. This improves the absorption effect of solid particles on transmitted solar radiation.

[0017] In a further preferred embodiment, when multiple inclined plates are arranged sequentially along the particle flow direction within the heat absorption chamber, adjacent inclined plates are connected, staggered vertically, or interleaved to form a multi-level inclined sliding channel. Solid particles enter through the particle inlet and slide down the surface of each inclined plate level, absorbing solar radiation during the sliding process, and finally exiting through the particle outlet. This inclined plate sliding structure can serve as a specific form of a hindered particle heat absorption structure, used to extend the residence time of particles within the heat absorption chamber and improve the uniformity of particle heat absorption.

[0018] Further preferably, the solid particles include one or more of sensible heat storage particles, thermochemical reaction particles, phase change heat storage particles, or mixtures thereof. The sensible heat absorption and storage particles are used to absorb and store heat through temperature increases, and preferably include one or more of ceramic particles, quartz sand, alumina particles, silicon carbide particles, sintered bauxite particles, mullite particles, cordierite particles, basalt particles, or mineral particles. The thermochemical reaction particles are used to undergo thermochemical reactions under solar heat and convert solar energy into chemical energy, and preferably include metal oxide particles, composite metal oxide particles, redox reaction particles, carbonate / oxide reaction particles, or other solar thermochemical reaction particles. The phase change heat storage particles are used to absorb or release heat through a phase change process, and preferably are coated phase change material particles, encapsulated phase change material particles, or phase change composite particles.

[0019] In other alternative embodiments, the heat-absorbing medium in the cavity-type solar heat-absorbing structure is not limited to solid particles, but can also be one or more of the following: gas, molten salt, heat-conducting oil, water, water vapor, liquid metal, thermochemical reactants, or mixtures thereof. When the heat-absorbing medium is a gas, the gas can flow through the heat-absorbing cavity, the porous heat absorber inside the cavity, or the heat exchange channel inside the cavity and absorb heat. When the heat-absorbing medium is molten salt, heat-conducting oil, water, water vapor, or liquid metal, the medium can flow through the flow channel, coil, heat exchange tube, or heat-absorbing wall surface provided in the heat-absorbing cavity and absorb heat transferred by solar radiation or the heat-absorbing structure inside the cavity. When the heat-absorbing medium is a thermochemical reactant, the reactant can be heated by solar energy and undergo thermochemical transformation inside the heat-absorbing cavity.

[0020] More preferably, the thermionic power generation light-transmitting window adopts a modular structure, and the thermionic power generation light-transmitting window includes multiple thermionic power generation modules, which are spliced ​​together to form the incident light window of the tower solar receiver.

[0021] Multiple thermionic power generation modules, based on their positions at the light inlet of the tower solar receiver and the incident light intensity, light spot distribution, or heat flux density of the corresponding areas, employ different cathode materials, cathode film thicknesses, transparent anode structures, or spectrally selective modulation layers. This results in different thermionic power generation light-transmitting sub-modules having different spectral absorptivity, spectral transmittance, or total transmittance. Areas with higher incident light intensity can be set to higher absorptivity or lower transmittance, while areas with lower incident light intensity can be set to higher transmittance. This spatially modulates the solar energy flow field passing through the thermionic power generation light-transmitting window and entering the receiver body, making the energy flux density distribution received by the receiver body more uniform. Furthermore, each of the multiple thermionic power generation light-transmitting sub-modules can be connected to an independently adjustable electrical load regulation module to adjust the output voltage, output current, output power, or operating temperature of each sub-module. This adapts to non-uniform focusing light spot distributions, reduces local hot spots, temperature gradients, and thermal stress concentration, and improves the operational stability of the thermionic power generation light-transmitting window and the receiver body.

[0022] According to a preferred embodiment of the present invention, the thermionic power generation light-transmitting window comprises: Outer light-transmitting protective layer; Thermionic emission cathode; A transparent anode is disposed opposite to the thermionic emission cathode; Inner light-transmitting protective layer; The inter-electrode region located between the thermionic emission cathode and the transparent anode; Window support and sealing structure; The outer light-transmitting protective layer is disposed on the sunlight incident side of the thermionic emission cathode to allow concentrated sunlight to pass through and to provide mechanical protection, environmental isolation or anti-oxidation protection for the thermionic emission cathode. The inner light-transmitting protective layer is disposed on the side of the transparent anode away from the inter-electrode region and is located between the transparent anode and the solar heat-absorbing unit. It is used to isolate particles, gases or other heat-absorbing media in the solar heat-absorbing unit while ensuring the passage of transmitted light. The interelectrode region is used to provide space for the transport of electrons emitted from the cathode to the transparent anode; The window support and sealing structure is used to support and fix the thermionic emission cathode, the transparent anode and the outer light-transmitting protective layer, maintain the relative position and inter-electrode distance between the thermionic emission cathode and the transparent anode, and seal the inter-electrode area to maintain a preset vacuum, gas pressure or vapor environment.

[0023] According to a preferred embodiment of the present invention, multiple thermionic generator modules are sealed and connected to a sealing structure via window support; the inter-electrode regions of adjacent thermionic generator modules are interconnected via an inter-electrode connection channel, which is connected to a vacuum interface, and the vacuum interface is connected to a vacuum pump via a valve.

[0024] According to a preferred embodiment of the present invention, the thermionic emission cathode includes a light-transmitting substrate and a cathode film disposed on the side of the light-transmitting substrate facing the interelectrode region; the cathode film emits electrons toward the interelectrode region under heating conditions and allows at least part of the incident light to pass through.

[0025] More preferably, the cathode film is formed from one or more of the following: semiconductor material, metal material, metal boride, metal carbide, metal nitride, carbon-based material, low electron affinity material, or doped material of the above materials, or composite material.

[0026] Most preferably, the semiconductor material includes one or more of silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, indium gallium nitride, silicon carbide, diamond or its doped materials, alloy materials and heterostructure materials; the metal material includes one or more of tungsten, molybdenum, tantalum, rhenium, hafnium or their alloys; the metal boride includes one or more of lanthanum hexaboride, cerium hexaboride or other rare earth borides; the carbon-based material includes one or more of graphene, few-layer graphene, carbon nanotube film or doped diamond.

[0027] The transparent anode is used to receive electrons emitted by the cathode film and conduct current, while allowing at least some solar radiation to pass through. The transparent anode includes a transparent substrate and a conductive layer. The conductive layer can be a transparent conductive oxide film such as ITO, FTO, AZO, GZO, or IZO, or one or more of ultrathin metal films, metal meshes, transparent conductive meshes, graphene, carbon nanotube transparent conductive films, and their composite structures. The transparent substrate can be quartz glass, fused silica, sapphire, borosilicate glass, transparent ceramics, or other high-temperature resistant and light-transmitting materials.

[0028] More preferably, the outer light-transmitting protective layer is further provided with an anti-reflection layer or a spectral modulation layer to reduce the reflection loss of incident sunlight or to adjust the spectrum incident on the thermionic emission cathode.

[0029] More preferably, the surface of the inner light-transmitting protective layer is further provided with an anti-reflection layer, a wear-resistant layer, an anti-pollution layer, or a spectral modulation layer to reduce the loss of transmitted light.

[0030] More preferably, the inter-electrode region is at least one of a vacuum environment or a low-pressure medium environment containing alkali metal vapor.

[0031] According to a preferred embodiment of the present invention, the external circuit is connected to the cathode and anode of the thermionic power generation light-transmitting window; the external circuit includes wires and an electrical load adjustment module, the electrical load adjustment module being used to adjust the output voltage, output current or output power of the thermionic power generation light-transmitting window; the electrical load adjustment module is an adjustable resistive load, an electronic load, a DC-DC converter circuit, an energy storage charging circuit or a combination thereof.

[0032] The operation method of a tower solar receiver system with an integrated thermionic power generation window includes: The heliostat field is used to reflect and focus sunlight onto the entrance port of the tower solar receiver; This allows concentrated sunlight to be incident onto the thermionic power generation light-transmitting window; The thermionic power generation transparent window selectively absorbs a portion of solar photons and outputs electrical energy. By configuring the band gap, absorption coefficient, thin film thickness, or optical control layer of the cathode material, at least a portion of solar photons are absorbed by the cathode and thermionic emission is generated, while the remaining sunlight passes through the thermionic power generation transparent window. Electrons in the cathode are emitted to the interelectrode region under the combined action of light and high temperature and are collected by the transparent anode. The cathode and the transparent anode are connected through an external circuit to form a current in the external circuit and output electrical energy to the load.

[0033] The remaining solar spectrum that is not absorbed or reflected passes through the thermionic power generation window, using the transmitted sunlight to heat the solar heat absorption unit inside the tower solar receiver.

[0034] According to a preferred embodiment of the present invention, the operation control unit further includes a parameter acquisition component, which is connected to the external circuit of the thermionic power generation light-transmitting window, the heat-absorbing medium conveying device, and the heliostat field control device. Based on the operating status of the thermionic power generation light-transmitting window and the solar heat-absorbing unit, the control unit coordinates and controls the power generation output and the high-temperature heat absorption process. The coordination and control process specifically includes: The parameter acquisition component acquires at least one of the following parameters: incident light intensity, temperature of the thermionic power generation light transmission window, output voltage of the thermionic power generation light transmission window, output current of the thermionic power generation light transmission window, transmitted light intensity, inlet temperature of the heat-absorbing medium, outlet temperature of the heat-absorbing medium, and flow rate of the heat-absorbing medium. The operation control unit pre-sets the allowable temperature range of the thermionic power generation light-transmitting window, the target outlet temperature range of the heat-absorbing medium, and the target electrical operating range of the thermionic power generation light-transmitting window; the allowable temperature range of the thermionic power generation light-transmitting window is determined based on the allowable operating temperature of at least one component among the cathode, transparent anode, transparent protective layer, support structure, and sealing structure; the target outlet temperature range of the heat-absorbing medium is determined based on the subsequent heat storage, power generation, or process heat requirements; the target electrical operating range is determined based on the output voltage-current characteristic or output power-voltage characteristic of the thermionic power generation light-transmitting window. When the temperature of the thermionic power generation light transmission window exceeds the upper limit of the allowable temperature range, the solar radiation flux received by the thermionic power generation light transmission window is reduced by changing the aiming point of the heliostat field, reducing the concentration intensity, or defocusing part of the heliostat field. The equivalent load of the external circuit can be adjusted according to the preset electrical characteristics of the thermionic power generation light transmission window to make it operate in the target electrical operating range and to help control the temperature of the thermionic power generation light transmission window. When the outlet temperature of the heat-absorbing medium is lower than the lower limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is reduced within the allowable flow range to prolong its heating time in the solar heat-absorbing unit. When the outlet temperature of the heat-absorbing medium is higher than the upper limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is increased first; if the temperature requirement is still not met, some heliostats are deflected from the thermionic power generation light transmission window or placed in a defocused state, and the aiming point of the heliostats is dispersed to reduce the local heat flux density and reduce the solar radiation power entering the solar heat-absorbing unit.

[0035] Through the above control, the coordinated operation between thermionic power generation output, transmitted solar energy flow, and the high-temperature heat absorption and storage process of the solar heat absorption unit is achieved.

[0036] The beneficial effects of this invention are as follows: This invention transforms the passive light-transmitting window of a traditional tower solar receiver into an active power generation window, enabling the window to simultaneously possess the functions of light transmission, power generation, and spectral energy flow regulation.

[0037] This invention utilizes a thermionic power generation window to selectively absorb a portion of solar photons for electrical energy output, while allowing the remaining solar spectrum to enter the receiver for high-temperature heat absorption, thus achieving graded utilization of solar energy spectrum.

[0038] This invention can be coupled with a tower solar absorber, so that concentrated sunlight first passes through the thermionic power generation window to generate electricity, and the unabsorbed solar radiation further passes through the window to heat the subsequent heat-absorbing medium, thereby realizing the synergy between power output and high-temperature heat absorption, heat storage or heat utilization processes.

[0039] This invention can achieve dynamic matching between power generation output and heat energy acquisition by adjusting the cathode material, thin film thickness, transparent anode structure, window cooling intensity, and heat absorption medium flow rate of the thermionic power generation window.

[0040] This invention can reduce the heat load of some high-energy spectra entering the receiver, which helps to alleviate the problems of local high heat flow and window thermal stress, and improves the functional integration of tower concentrating solar energy systems.

[0041] This invention is applicable to closed particle receivers, cavity particle receivers, pressurized particle receivers, solar thermochemical reactors, air receivers, and other tower-type concentrating solar energy receiving systems that require light-transmitting windows. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the overall structure of the tower-type concentrated solar power receiving system with integrated thermionic power generation window according to the present invention.

[0043] Figure 2 This is a schematic cross-sectional view of the thermionic power generation window of the present invention.

[0044] Figure 3 This is a schematic cross-sectional view of the free-fall solid particle heat absorber with integrated thermionic power generation window of the present invention.

[0045] Figure 4 This is a schematic diagram of the overall structure of the tube bundle-type solid particle heat absorber with integrated thermionic power generation window of the present invention.

[0046] Figure 5 This is a schematic diagram of the circumferential arrangement of the tube bundle-type solid particle heat absorber with integrated thermionic power generation window of the present invention.

[0047] Figure 6 This is a partially enlarged cross-sectional schematic diagram of the internal particle flow channel of a tube bundle-type solid particle receiver with an integrated thermoelectric power generation window.

[0048] Figure 7 This is a schematic diagram of the inclined sliding particle heat absorber structure with integrated thermionic power generation window of the present invention.

[0049] Figure 8 This is a schematic diagram of the modular thermionic power generation window of the present invention.

[0050] Among them, 1. Heliostat field, 2. Tower solar receiver, 201. Thermionic power generation light-transmitting window, 202. Solar heat absorption unit, 203. Tower solar receiver shell, 3. External circuit, 4. Operation control unit, 5. Tower, 2001. Outer light-transmitting protective layer, 2002. Thermionic emission cathode, 2003. Interelectrode region, 2004. Transparent anode, 2005. Inner light-transmitting protective layer, 2006. Window support and sealing structure, 2002-1. Light-transmitting substrate, 2002-2. Cathode film; 6. Free-fall solid particle heat absorption structure; 601. Cold particle inlet hopper; 602. Particle curtain heat absorption zone; 603. Hot particle collection hopper; 7. Cold particle supply device; 8. Particle utilization device; 9. Particle distribution tank; 10. Particle collection tank; 11. Particle flow heat absorption pipe; 12. Cold particle inlet; 13. Hot particle outlet; 14. Inclined plate; 201-1. Thermionic generator module; 201-2. Inter-electrode connection channel; 201-3. Vacuum interface; 201-4. Valve; 201-5. Vacuum pump. Detailed Implementation

[0051] The present invention will be further defined below with reference to the accompanying drawings and embodiments, but is not limited thereto.

[0052] Example 1 Tower solar receiver systems with integrated thermoelectric power generation windows, such as Figure 1 As shown, it includes: Heliostat field 1; Tower solar receiver 2; Thermionic power generation light-transmitting window 201 is set at the light-inlet of the tower solar receiver 2; Solar heat absorption unit 202 located inside tower solar receiver 2; External circuit 3 connected to the thermionic power generation light-transmitting window 201; Operation control unit 4; In this system, the heliostat field 1 reflects and focuses sunlight onto the incident light port of the tower solar receiver 2 located on the tower 5. A thermionic power generation window 201 is positioned at the incident light port of the tower solar receiver 2 to replace or partially replace the traditional passive light-transmitting window. The thermionic power generation window 201 selectively absorbs a portion of the photons in the incident concentrated sunlight and outputs electrical energy through the external circuit 3. The remaining solar spectrum that is not absorbed or reflected passes through the thermionic power generation window 201 and enters the interior of the tower solar receiver 2, where it is absorbed by the solar heat absorption unit 202. The external circuit 3 and the operation control unit 4 are used to coordinate and adjust the power output of the thermoelectric power generation light-transmitting window 201 and the solar energy utilization process transmitted into the tower solar receiver 2 according to the solar irradiation conditions, the operating status of the thermoelectric power generation light-transmitting window 201, the heat absorption status of the tower solar receiver 2 and the heat storage requirements, so as to keep the thermoelectric power generation light-transmitting window 201 and the tower solar receiver 2 within the preset operating range.

[0053] Furthermore, the operation control unit 4 also includes a parameter detection component, which is connected to the external circuit 3 and the corresponding actuator; the parameter detection component is used to detect at least one of the following parameters: input light intensity of the heliostat field 1, light spot distribution at the entrance of the tower solar receiver 2, temperature of the thermal electron power generation light transmission window 201, output voltage of the thermal electron power generation light transmission window 201, output current of the thermal electron power generation light transmission window 201, transmitted light intensity, outlet temperature of the heat absorption medium, or heat storage state. The operation control unit 4 generates control commands based on the detection results and sends the control commands to at least one of the electrical load adjustment module, the heat absorption medium conveying device, the particle conveying device, or the heliostat field 1 control device to adjust the electrical load of the power generation window, the flow rate of the heat absorption medium, the particle circulation rate, or the aiming strategy of the heliostat field 1. The adjustment of the heat-absorbing medium flow rate or particle circulation rate is used to change the absorption capacity of the tower solar receiver 2 for transmitted solar energy and the outlet temperature of the heat-absorbing medium; the adjustment of the aiming strategy of the heliostat field 1 is used to change the incident light intensity or spot distribution at the thermionic power generation light transmission window 201 and the inlet of the tower solar receiver 2.

[0054] Furthermore, the external circuit 3 is connected to the cathode and anode of the thermionic power generation light-transmitting window 201; the external circuit 3 includes wires and an electrical load adjustment module, which is used to adjust the output voltage, output current or output power of the thermionic power generation light-transmitting window 201; the electrical load adjustment module is an adjustable resistive load, an electronic load, a DC-DC converter circuit, an energy storage charging circuit or a combination thereof.

[0055] Example 2 The tower solar receiver system with integrated thermionic power generation window as described in Example 1 differs in that: The tower solar receiver 2 is a tube-type heat-absorbing structure. This embodiment uses a tube-type solid particle heat-absorbing structure as an example for explanation. The tower solar receiver 2 adopts a heat-absorbing tube structure that integrates light-transmitting thermal electron power generation; such as Figure 4 As shown, it includes a particle distribution tank 9, a particle collection tank 10, and a plurality of light-transmitting thermoelectric power generation particle flow heat absorption pipes 11 disposed between the particle distribution tank 9 and the particle collection tank 10. The particle distribution tank 9 is provided with a cold particle inlet 12, and the particle collection tank 10 is provided with a hot particle outlet 13. The upper end of each light-transmitting thermoelectric power generation particle flow heat absorption pipe 11 is connected to the particle distribution tank 9, and the lower end is connected to the particle collection tank 10.

[0056] like Figure 5 As shown, multiple light-transmitting thermoelectric power generation particle flow heat absorption tubes 11 are arranged circumferentially along the particle distribution tank 9, forming a tube bundle-type particle heat absorption structure. Cold particles enter the particle distribution tank 9 through the cold particle inlet 12, are distributed to each light-transmitting thermoelectric power generation particle flow heat absorption tube 11, and flow downward along the particle flow channel inside the tube under the action of gravity; the heat-absorbing particles enter the particle collection tank 10 and are finally discharged from the hot particle outlet 13. The solid particles can form free-fall particle flow, obstructed free-fall particle flow, moving bed particle flow, or other particle flow forms.

[0057] like Figure 6As shown, each thermionic power generation particle flow absorber tube 11 has an internal particle flow channel, and its tube wall is an integrated thermionic power generation structure. Along the direction of incident sunlight propagation, the tube wall sequentially includes an outer light-transmitting protective layer 2001, a light-transmitting substrate 2002-1, a cathode thin film 2002-2, an interelectrode region 2003, a transparent anode 2004, and an inner light-transmitting protective layer 2005. The inner light-transmitting protective layer 2005 is located between the transparent anode 2004 and the particle flow channel inside the tube, and is used to reduce the impact of particle friction, collision, dust deposition, and thermal shock on the transparent anode 2004.

[0058] After concentrated solar energy is incident on the light-transmitting thermoelectric particle flow absorber tube 11, some of the solar radiation is selectively absorbed by the cathode film 2002-2, and electrons are emitted under the action of light and heat, which outputs electrical energy through the external circuit 3. The solar radiation that is not absorbed by the cathode film 2002-2 passes through the interelectrode region 2003, the transparent anode 2004 and the inner light-transmitting protective layer 2005 in sequence, enters the particle flow channel inside the tube and is absorbed by the solid particles, causing the particle temperature to rise. Multiple light-transmitting thermoelectric particle flow absorber tubes 11 can be connected to the external circuit 3 individually, or they can be combined and output through series, parallel or series-parallel combination.

[0059] Furthermore, the particle flow channel of the light-transmitting thermoelectric power generation particle flow absorber tube 11 can be equipped with one or more of the following structures: a blocking structure, a guiding structure, a turbulence structure, a heat transfer enhancement structure, or a porous media structure, to adjust the particle's falling speed, flow path, residence time, distribution uniformity, or heat transfer area. The blocking structure, guiding structure, turbulence structure, heat transfer enhancement structure, or porous media structure can be one or more of the following: baffles, deflectors, perforated plates, grids, guide vanes, ribs, packing materials, wire mesh, honeycomb structures, foamed metal, or porous ceramics. Through these structures, a particle flow state can be formed, including hindered free fall, staged fall, reversible flow, or delayed fall, thereby improving the particle's absorption effect of transmitted solar energy.

[0060] In other alternative embodiments, the tower solar receiver 2 is not limited to using solid particles as the heat-absorbing medium. The particle distribution tank 9 and particle collection tank 10 can also be replaced with inlet distribution components and outlet collection components suitable for fluid media. The heat-absorbing medium can be one or more of solid particles, molten salt, gas, heat transfer oil, water, water vapor, liquid metal, or mixtures thereof. When the heat-absorbing medium is molten salt, gas, heat transfer oil, water, water vapor, or liquid metal, the heat-absorbing medium can flow along the medium flow channel inside the light-transmitting thermoelectric power generation heat-absorbing tube under the action of pumping, pressure difference, natural circulation, or gravity, and absorb the heat transferred by transmitted sunlight or the tube wall. The obstruction structure, flow guiding structure, turbulence structure, heat exchange enhancement structure, or porous medium structure set in the tube can also be used to adjust the flow path, mixing state, and heat exchange process of the fluid medium.

[0061] With the above structure, this embodiment can achieve thermionic power generation by utilizing the cathode film 2002-2 and transparent anode 2004 in the transparent tube wall while the heat-absorbing medium flows continuously along the tube channel and absorbs heat. Through the spectral selective absorption and transmission function of the tube wall, part of the solar energy can be used for front-end power generation, and the remaining solar energy can enter the tube medium flow channel to heat the heat-absorbing medium, thereby realizing the synergistic utilization of concentrated solar energy for power generation and heat absorption.

[0062] Example 3 The tower solar receiver system with integrated thermionic power generation window described in Example 2 differs in that: The solar heat absorption unit 202 is at least one of a sensible heat absorption unit, a phase change heat absorption unit, or a thermochemical reaction unit.

[0063] Sensible heat absorption units, based on the primary medium responsible for heat absorption and transport, are at least one of the following: liquid working fluid receivers, gas working fluid receivers, or solid particle receivers. Liquid working fluid receivers use a liquid heat transfer medium as the primary heat transfer medium, including molten salt, heat transfer oil, liquid metal, water, or other liquid media capable of maintaining a flowing state at the operating temperature. Gas working fluid receivers use a gas as the primary heat transfer medium, including air, carbon dioxide, helium, nitrogen, water vapor, or mixtures thereof. Solid particle receivers use discrete solid particles capable of flowing, falling, being transported, or circulating as the solar radiation absorption medium, heat transfer medium, or heat storage medium. The particle medium receives transmitted solar radiation and absorbs heat in at least one of the following motion or arrangement states: free fall, obstructed fall, sliding along an inclined bearing surface, gravity-driven moving bed, gas-solid fluidization, or fixed bed. The particle medium is at least one of the following: ceramic particles, alumina particles, silicon carbide particles, quartz sand particles, or other high-temperature resistant particles.

[0064] Phase change heat absorption units use a medium that undergoes vaporization, melting, or other phase changes during the heat absorption process as the heat absorption medium, including water / steam heat absorbers or phase change material heat absorbers.

[0065] The thermochemical reaction unit uses solar radiation passing through the power generation window to heat the reactants, thereby driving the thermochemical reaction and converting solar energy into chemical energy.

[0066] like Figure 3 As shown, the solar heat absorption unit 202 adopts a cavity-type solid particle heat absorption structure. This embodiment uses the free-fall solid particle heat absorption structure 6 as an example for explanation. The free-fall solid particle heat absorption structure 6 includes a cold particle inlet hopper 601, a particle curtain heat absorption zone 602, and a hot particle collection hopper 603. The cold particle inlet hopper 601 is located at the upper part of the tower solar receiver shell 203, and the hot particle collection hopper 603 is located at the lower part of the tower solar receiver shell 203. A free-falling particle channel is formed between the cold particle inlet hopper 601 and the hot particle collection hopper 603. Solid particles enter the tower solar receiver 2 through the cold particle supply device 7 and the cold particle inlet hopper 601 in sequence, and form a continuous or intermittent free-fall particle curtain under the action of gravity. After absorbing solar radiation through the particle curtain heat absorption zone 602, they fall into the hot particle collection hopper 603 and are discharged or transported to the subsequent particle utilization device 8.

[0067] Along the incident direction of concentrated solar energy, the thermionic emission power generation window 201 sequentially includes an outer light-transmitting protective layer 2001, a light-transmitting substrate 2002-1, a cathode thin film 2002-2, an interelectrode region 2003, a transparent anode 2004, and an inner light-transmitting protective layer 2005. The working principle of the power generation window 201 is consistent with that in Example 1. The thermionic emission power generation window 201 selectively absorbs a portion of solar photons, and the unabsorbed solar radiation enters the particle curtain heat absorption zone 602 and is absorbed by the freely falling solid particles. After absorbing the transmitted solar radiation, the solid particles' temperature rises, thereby converting the transmitted solar energy into the particle's thermal energy. The heated solid particles are collected in the hot particle collection hopper 603 and can be further transported to the subsequent particle utilization device 8.

[0068] The outlet shape, size, and particle discharge rate of the cold particle inlet hopper 601 are set according to the required width, thickness, and particle mass flow rate of the free-fall particle curtain, so that the particle curtain covers at least part of the area that transmits solar radiation.

[0069] The solid particles are preferably sensible heat-absorbing and heat-storing particles, including one or more of ceramic particles, quartz sand, alumina particles, silicon carbide particles, sintered bauxite particles, mullite particles, cordierite particles, basalt particles, or mineral particles. In other optional embodiments, the solid particles may also be thermochemical reaction particles, encapsulated phase change heat storage particles, phase change composite particles, or mixtures thereof; wherein, the thermochemical reaction particles include metal oxide particles, composite metal oxide particles, redox reaction particles, or carbonate / oxide reaction particles, used to undergo thermochemical transformation under solar heat; the encapsulated phase change heat storage particles or phase change composite particles are used to absorb or release heat through a phase change process.

[0070] The particle size, mass flow rate, falling velocity, and particle curtain thickness of the solid particles can be adjusted according to the incident solar flux density of the receiver, the outlet temperature of the target particles, and the transmitted light intensity of the power generation window.

[0071] Furthermore, Figure 3 The free-falling particle curtain shown is only a preferred embodiment of the cavity-type solid particle heat absorption structure. In other optional embodiments, the particle curtain heat absorption zone 602 can also be provided with a blocking structure, a flow guiding structure, a dispersion structure, or a porous media structure to adjust the falling speed, residence time, flow path, or particle distribution uniformity of the solid particles, so that the solid particles form a hindered free-falling particle flow, a staged falling particle flow, a moving bed particle flow, or a porous media particle flow.

[0072] The operation control unit 4 generates corresponding control commands based on at least one of the following parameters: input light intensity of the heliostat field 1, light spot distribution at the solar radiation inlet, temperature of the thermionic emission power generation window 201, output voltage of the thermionic emission power generation window 201, output current of the thermionic emission power generation window 201, transmitted light intensity, particle outlet temperature, or thermal storage state. These control commands are used to adjust the aiming strategy of the external circuit 3, the cold particle supply device 7, the particle utilization device 8, or the heliostat field 1 to coordinate the electrical energy output of the thermionic power generation window with the heat absorption process of the free-falling particles.

[0073] When the incident solar flux density increases, the temperature of the thermionic power generation window 201, the power generation output, and the particle outlet temperature can be kept within the preset operating range by increasing the particle mass flow rate, increasing the particle curtain thickness, adjusting the particle circulation rate, or adjusting the electrical load of the thermionic power generation window 201. When the incident solar flux density decreases, the particle mass flow rate can be reduced accordingly or the heliostat field aiming strategy can be adjusted to improve the matching degree between the transmitted solar energy and the heat absorption demand of the particles.

[0074] The above structure enables the spectral grading and utilization of concentrated solar energy, as well as the coordinated operation of power output and particle thermal storage processes.

[0075] Example 4 The tower solar receiver system with integrated thermionic power generation window described in Example 3 differs in that: like Figure 7 As shown, the tower solar receiver 2 is equipped with multiple inclined plates 14 arranged sequentially along the particle flow direction. Adjacent inclined plates 14 are connected to each other or staggered to form a multi-level inclined sliding channel. Solid particles enter through the particle inlet and slide down the surface of each level of the inclined plate 14 step by step, and are discharged through the particle outlet. The number of inclined plates 14 can also be set to one or more according to the particle flow rate, target residence time and heat absorption requirements.

[0076] like Figure 7 As shown, thermionic power generation windows 201 are respectively provided on opposite sides of the receiver housing, allowing concentrated solar radiation to be transmitted to the particle sliding area from different directions. The number and orientation of the power generation windows are not limited to the structure shown in the figure, and can also be set in one or more directions of the receiver housing according to the arrangement of the heliostat field 1, the direction of incident light, and the light receiving requirements of the particles.

[0077] After concentrated solar energy is incident on the thermionic power generation window 201, some of the solar energy is converted into electrical energy, while the remaining solar radiation shines through the power generation window onto the sliding solid particles and is converted into heat energy. The inclined surface can guide and slow down the particle flow, prolonging the residence time of the particles in the light-receiving area, thereby achieving synergistic utilization of solar power generation and heat absorption by solid particles.

[0078] Example 5 The tower solar receiver system with integrated thermionic power generation window as described in Example 1 differs in that: The thermoelectric power generation light transmission window 201 adopts a modular structure. The thermoelectric power generation light transmission window 201 includes multiple thermoelectric power generation modules 201-1. The multiple thermoelectric power generation modules 201-1 are spliced ​​together to form the incident light window of the tower solar receiver 2.

[0079] Multiple thermionic power generation modules 201-1 employ different cathode materials, cathode film 2002-2 thicknesses, or optical control layers based on their positions at the light entrance of the tower solar receiver 2 and the incident light intensity of the corresponding region. This allows different thermionic power generation modules 201-1 to have different spectral absorptivity or transmittance. Each thermionic power generation module 201-1 is connected to an independently adjustable electrical load regulation module, thereby adjusting the temperature, output voltage, output current, or output power of each module 201-1 to adapt to the non-uniform focusing light spot distribution at the light entrance of the tower solar receiver 2. In one configuration, the light entrance of the receiver can be divided into a high-intensity region and a low-intensity region. The power generation window module located in the high-intensity region employs a higher spectral selective absorptivity and a higher front-end power generation utilization ratio to reduce the local energy flux density entering the receiver body after passing through the thermionic power generation transmission window in that region. The power generation window module located in the low-intensity region employs a higher solar transmittance to increase the transmitted energy flux entering the receiver body in that region. The power generation window modules in different regions are connected to independent electrical load regulation branches, enabling each power generation window module to operate in the corresponding preset electrical operating range according to the incident light intensity, operating temperature and output power of its region. This achieves spatial modulation of the incident energy flow field of the receiver body, reducing local hot spots, temperature gradients and uneven thermal stress.

[0080] like Figure 2 As shown, the thermionic power generation light-transmitting window 201 includes: Outer light-transmitting protective layer 2001; Thermionic emission cathode 2002; A transparent anode 2004 is disposed opposite to the thermionic emission cathode 2002; Inner translucent protective layer 2005; The inter-electrode region 2003 is located between the thermionic emission cathode 2002 and the transparent anode 2004; Window support and sealing structure 2006; The transparent anode 2004 is disposed opposite to the thermionic emission cathode 2002 and separated by the inter-electrode region 2003.

[0081] An outer light-transmitting protective layer 2001 is disposed on the sunlight incident side of the thermionic emission cathode 2002 to allow concentrated sunlight to pass through and to provide mechanical protection, environmental isolation or anti-oxidation protection for the thermionic emission cathode 2002. The inner light-transmitting protective layer 2005 is disposed on the side of the transparent anode 2004 away from the inter-electrode region 2003 and is located between the transparent anode 2004 and the solar heat absorption unit 202. It is used to isolate particles, gases or other heat-absorbing media in the solar heat absorption unit 202 while ensuring the passage of transmitted light; and to reduce the impact of particle impact, friction wear, dust deposition, thermal shock and chemical corrosion on the transparent anode 2004.

[0082] The inter-electrode region 2003 provides space for the transport of electrons emitted from the cathode to the transparent anode 2004; the spacing of the inter-electrode regions 2003 is maintained by the window support and the sealing structure 2006. The window support and sealing structure 2006 is used to support and fix the thermionic emission cathode 2002, the transparent anode 2004 and the outer light-transmitting protective layer 2001, maintain the relative position and inter-electrode distance between the thermionic emission cathode 2002 and the transparent anode 2004, and seal the inter-electrode area 2003 to maintain a preset vacuum, gas pressure or vapor environment.

[0083] like Figure 8 As shown, multiple thermionic generator modules 201-1 are sealed and connected to a sealing structure 2006 via window supports. The inter-electrode regions 2003 of adjacent thermionic generator modules 201-1 are interconnected via an inter-electrode connection channel 201-2, which is connected to a vacuum interface 201-3. The vacuum interface 201-3 is connected to a vacuum pump 201-5 via a valve 201-4. A single vacuum pump 201-5 can simultaneously evacuate the inter-electrode regions 2003 of multiple thermionic generator modules 201-1 and maintain a preset low-pressure or vacuum environment.

[0084] Each thermionic generator module 201-1 is electrically independent, with its cathode and anode connected to the corresponding external circuit 3 via electrode leads. When there are differences in solar irradiance, window temperature, or transmission requirements at different locations, the operating status of each thermionic generator module 201-1 can be adjusted separately. For non-uniform light spot areas in the tower solar receiver 2, different window modules can use different cathode film thicknesses 2002-2 and different transmittances to adapt to local light intensity and temperature distributions.

[0085] The thermionic emission cathode 2002 includes a light-transmitting substrate 2002-1 and a cathode film 2002-2 disposed on the side of the light-transmitting substrate 2002-1 facing the inter-electrode region 2003; the cathode film 2002-2 emits electrons toward the inter-electrode region 2003 under heated conditions and allows at least part of the incident light to pass through.

[0086] The cathode thin film 2002-2 is formed from one or more of the following: semiconductor materials, metallic materials, metal borides, metal carbides, metal nitrides, carbon-based materials, low electron affinity materials, or doped materials of the above materials, or composite materials.

[0087] Semiconductor materials include one or more of silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, indium gallium nitride, silicon carbide, diamond or its doped materials, alloy materials and heterostructure materials; metallic materials include one or more of tungsten, molybdenum, tantalum, rhenium, hafnium or their alloys; metal borides include one or more of lanthanum hexaboride, cerium hexaboride or other rare earth borides; carbon-based materials include one or more of graphene, few-layer graphene, carbon nanotube films or doped diamond.

[0088] The transparent anode 2004 is used to receive electrons emitted by the cathode film 2002-2 and conduct current, while allowing at least some solar radiation to pass through. The transparent anode 2004 includes a transparent substrate and a conductive layer. The conductive layer can be a transparent conductive oxide film such as ITO, FTO, AZO, GZO, or IZO, or one or more of ultrathin metal films, metal meshes, transparent conductive meshes, graphene, carbon nanotube transparent conductive films, and their composite structures. The transparent substrate can be quartz glass, fused silica, sapphire, borosilicate glass, transparent ceramics, or other high-temperature resistant and light-transmitting materials.

[0089] The cathode thin film 2002-2 is configured as a semiconductor material to achieve photon-enhanced thermionic emission. The cathode thin film 2002-2 selectively absorbs a portion of the high-energy photons in the incident light to generate photogenerated carriers and enhance thermionic emission, while allowing at least a portion of the remaining solar radiation to be transmitted to subsequent solar energy utilization units, thereby improving the overall utilization rate of solar energy.

[0090] The outer light-transmitting protective layer 2001 is also provided with an anti-reflection layer or a spectral modulation layer to reduce the reflection loss of incident sunlight or to adjust the spectrum incident on the thermionic emission cathode 2002.

[0091] The inner light-transmitting protective layer 2005 also has an anti-reflection layer, a wear-resistant layer, an anti-fouling layer, or a spectral modulation layer on its surface to reduce transmitted light loss and improve the long-term operational stability of the device.

[0092] The interpolar region 2003 is at least one of a vacuum environment or a low-pressure medium environment containing alkali metal vapor.

[0093] Concentrated solar energy first illuminates the thermionic power generation window 201. Thermionic emission cathode 2002 in the thermionic power generation window 201 selectively absorbs a portion of the solar photons and generates thermionic emission. The emitted electrons pass through the interelectrode region 2003 and are collected by the transparent anode 2004, and output as electrical energy via the external circuit 3. The remaining solar spectrum that is not absorbed or reflected is absorbed and utilized by the solar energy absorption unit 202 through the thermionic power generation window 201.

[0094] This embodiment transforms the entrance window of the tower solar receiver 2 from a traditional light-transmitting component into an active solar energy conversion component that combines light transmission, power generation, and spectral control functions, thereby realizing spectral hierarchical utilization, synergistic power generation and heat absorption, and energy flow control in the tower concentrating solar energy system.

[0095] Example 6 The operation method of a tower solar receiver system with an integrated thermionic power generation window includes: The heliostat field 1 is used to reflect and focus sunlight onto the entrance of the tower solar receiver 2; This allows concentrated sunlight to be incident onto the thermionic power generation light-transmitting window 201; The thermionic power generation transparent window 201 selectively absorbs a portion of solar photons and outputs electrical energy. By configuring the band gap, absorption coefficient, thin film thickness, or optical control layer of the cathode material, at least a portion of solar photons are absorbed by the cathode and thermionic emission is generated, while the remaining sunlight passes through the thermionic power generation transparent window 201. Electrons in the cathode are emitted to the interelectrode region 2003 under the combined action of light and high temperature and are collected by the transparent anode 2004. The cathode and the transparent anode 2004 are connected through an external circuit 3 to form a current in the external circuit 3 and output electrical energy to the load.

[0096] The remaining solar spectrum that is not absorbed or reflected passes through the thermal electron power generation window 201; The solar heat absorption unit 202 inside the tower-type solar receiver 2 is heated by transmitted sunlight.

[0097] The operation control unit 4 also includes a parameter acquisition component, which is connected to the external circuit 3 of the thermionic power generation light-transmitting window 201, the heat absorption medium conveying device, and the heliostat field 1 control device. Based on the operating status of the thermionic power generation light-transmitting window 201 and the solar heat absorption unit 202, it coordinates and controls the power generation output and the high-temperature heat absorption process. The coordination and control process specifically includes: The parameter acquisition component acquires at least one of the following parameters: incident light intensity, temperature of the thermionic power generation light transmission window 201, output voltage of the thermionic power generation light transmission window 201, output current of the thermionic power generation light transmission window 201, transmitted light intensity, inlet temperature of the heat-absorbing medium, outlet temperature of the heat-absorbing medium, and flow rate of the heat-absorbing medium. The operation control unit 4 pre-sets the allowable temperature range of the thermionic power generation light-transmitting window 201, the target outlet temperature range of the heat-absorbing medium, and the target electrical operating range of the thermionic power generation light-transmitting window 201. The allowable temperature range of the thermionic power generation light-transmitting window 201 is determined based on the allowable operating temperature of at least one component among the cathode, transparent anode 2004, transparent protective layer, support structure, and sealing structure. The target outlet temperature range of the heat-absorbing medium is determined based on the subsequent heat storage, power generation, or process heat requirements. The target electrical operating range is determined based on the output voltage-current characteristic or output power-voltage characteristic of the thermionic power generation light-transmitting window 201. When the temperature of the thermionic power generation light transmission window 201 exceeds the upper limit of the allowable temperature range, the solar radiation flux received by the thermionic power generation light transmission window 201 is reduced by changing the aiming point of the heliostat field 1, reducing the light concentration intensity, or defocusing part of the heliostat field 1. The equivalent load of the external circuit 3 can be adjusted according to the preset electrical characteristics of the thermionic power generation light transmission window so that it operates in the target electrical operating range and assists in controlling the temperature of the thermionic power generation light transmission window 201. When the outlet temperature of the heat-absorbing medium is lower than the lower limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is reduced within the allowable flow range to prolong its heating time in the solar heat-absorbing unit. When the outlet temperature of the heat-absorbing medium is higher than the upper limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is increased first; if the temperature requirement is still not met, some heliostats are deviated from the thermionic power generation light-transmitting window 201 or are in a defocused state, and the aiming point of the heliostats is dispersed to reduce the local heat flux density and reduce the solar radiation power entering the solar heat-absorbing unit 202.

[0098] Through the above control, the coordinated operation between thermionic power generation output, transmitted solar energy flow, and the high-temperature heat absorption and storage process of solar heat absorption unit 202 is realized.

Claims

1. A tower solar energy receiving system with an integrated thermionic power generation window, characterized in that, include: Heliostat field; Tower solar receiver; Thermionic power generation light-transmitting window is provided at the light entrance of the tower solar receiver; A solar heat absorption unit located inside the tower-type solar receiver; External circuitry connected to the thermionic power generation light-transmitting window; Operation control unit; The heliostat field is used to reflect and focus sunlight onto the thermionic power generation light-transmitting window. The thermionic power generation light-transmitting window selectively absorbs some photons in the incident concentrated sunlight and outputs electrical energy through an external circuit. The remaining solar spectrum that is not absorbed or reflected passes through the thermionic power generation light-transmitting window and enters the tower solar receiver, where it is absorbed by the solar heat absorption unit. The external circuit and operation control unit are used to coordinate and adjust the power output of the thermoelectric power generation window and the solar energy utilization process transmitted into the tower solar receiver according to solar irradiance conditions, the operating status of the thermoelectric power generation window, the heat absorption status of the tower solar receiver, and the heat storage requirements, so as to keep the thermoelectric power generation window and the tower solar receiver within a preset operating range.

2. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 1, characterized in that, The tower solar receiver is a tube bundle heat absorption structure, which adopts an integrated light-transmitting thermoelectric power generation heat absorption tube structure; the tower solar receiver includes a medium distribution component, a medium collection component, and multiple light-transmitting thermoelectric power generation heat absorption tubes disposed between the medium distribution component and the medium collection component; The medium distribution component is equipped with a low-temperature medium inlet, and the medium collection component is equipped with a high-temperature medium outlet. The inlet end of each light-transmitting thermoelectric power generation heat absorption tube is connected to the medium distribution component, and the outlet end is connected to the medium collection component. Multiple light-transmitting thermal-electronic power generation heat-absorbing tubes are arranged at intervals along the medium distribution assembly to form a tube bundle heat-absorbing structure; the low-temperature heat-absorbing medium enters the medium distribution assembly from the low-temperature medium inlet, and is distributed to each light-transmitting thermal-electronic power generation heat-absorbing tube by the medium distribution assembly. After absorbing the heat transmitted by the solar energy or the heat transferred by the tube wall, it enters the medium collection assembly and is discharged from the high-temperature medium outlet. More preferably, the medium flow channel of the light-transmitting thermoelectric power generation heat absorber tube is provided with one or more of the following: a blocking structure, a guiding structure, a turbulence structure, a heat exchange enhancement structure, or a porous medium structure, so as to adjust the flow path, residence time, mixing state, or heat exchange area of ​​the heat absorber medium.

3. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 1, characterized in that, The operation control unit also includes a parameter detection component, which is connected to an external circuit and a corresponding actuator. The parameter detection component is used to detect at least one of the following parameters: input light intensity of the heliostat field, light spot distribution at the entrance of the tower solar receiver, temperature of the thermionic power generation light transmission window, output voltage of the thermionic power generation light transmission window, output current of the thermionic power generation light transmission window, transmitted light intensity, outlet temperature of the heat absorption medium, or heat storage state. The operation control unit generates control commands based on the detection results and sends the control commands to at least one of the following: electrical load adjustment module, heat-absorbing medium conveying device, particle conveying device, or heliostat field control device, in order to adjust the electrical load of the power generation window, the flow rate of the heat-absorbing medium, the particle circulation rate, or the heliostat field aiming strategy. The adjustment of the heat-absorbing medium flow rate or particle circulation rate is used to change the absorption capacity of the tower solar receiver for transmitted solar energy and the outlet temperature of the heat-absorbing medium; the adjustment of the heliostat field aiming strategy is used to change the incident light intensity or spot distribution at the thermionic power generation transmission window and the inlet of the tower solar receiver.

4. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 1, characterized in that, The solar energy absorption unit is at least one of a sensible heat absorption unit, a phase change heat absorption unit, or a thermochemical reaction unit.

5. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 1, characterized in that, The solar heat absorption unit adopts a cavity-type solar heat absorption structure, which includes a receiver shell, a heat absorption cavity, and a heat absorption medium flow area disposed within the heat absorption cavity. The thermionic power generation light transmission window is disposed at the light inlet of the receiver shell and constitutes the incident window of the heat absorption cavity. Concentrated solar radiation first irradiates the thermionic power generation light transmission window, in which part of the solar radiation is absorbed by the thermionic power generation light transmission window and used for thermionic power generation. The unabsorbed solar radiation passes through the thermionic power generation light transmission window and enters the heat absorption cavity, where it is absorbed and utilized by the heat absorption medium. More preferably, the heat-absorbing medium is solid particles, and the cavity solar heat-absorbing structure is a cavity solid particle heat-absorbing structure, including a cold particle inlet hopper, a particle heat-absorbing zone, and a hot particle collection hopper; the cold particle inlet hopper is located at the upper part of the receiver shell, the hot particle collection hopper is located at the lower part of the receiver shell, and a particle flow channel is formed between the cold particle inlet hopper and the hot particle collection hopper. More preferably, the flow pattern of solid particles in the particle heat absorption zone includes one or more of the following: free-fall particle curtain, obstructed free-fall particle flow, staged falling particle flow, inclined plate sliding particle flow, moving bed particle flow, fluidized particle flow, or particle flow in porous media; the particle heat absorption zone is provided with a blocking structure, a guiding structure, a dispersing structure, a turbulence structure, an inclined sliding structure, or a porous media structure to adjust the falling speed, residence time, flow path, particle curtain thickness, or particle distribution uniformity of the solid particles; In a further preferred embodiment, when multiple inclined plates are arranged sequentially along the particle flow direction in the heat absorption chamber, adjacent inclined plates are connected to each other, staggered vertically or interleaved to form a multi-level inclined sliding channel; after solid particles enter from the particle inlet, they slide down the surface of each level of inclined plate step by step, and absorb solar radiation during the sliding process, and are finally discharged from the particle outlet. More preferably, the solid particles include one or more of sensible heat storage particles, thermochemical reaction particles, phase change heat storage particles, or a mixture thereof; More preferably, the thermionic power generation light-transmitting window adopts a modular structure, and the thermionic power generation light-transmitting window includes multiple thermionic power generation modules, which are spliced ​​together to form the incident light window of the tower solar receiver. Multiple thermionic power generation modules employ different cathode materials, cathode film thicknesses, transparent anode structures, or spectral selectivity control layers, depending on their position at the light inlet of the tower solar receiver and the incident light intensity, light spot distribution, or heat flux density in the corresponding area. This results in different thermionic power generation light-transmitting sub-modules having different spectral absorptivity, spectral transmittance, or total transmittance. Each of the multiple thermionic power generation light-transmitting sub-modules is also connected to an independently adjustable electrical load regulation module to adjust the output voltage, output current, output power, or operating temperature of each sub-module.

6. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 1, characterized in that, The thermionic power generation light-transmitting window includes: Outer light-transmitting protective layer; Thermionic emission cathode; A transparent anode is disposed opposite to the thermionic emission cathode; Inner light-transmitting protective layer; The inter-electrode region located between the thermionic emission cathode and the transparent anode; Window support and sealing structure; The outer light-transmitting protective layer is disposed on the sunlight incident side of the thermionic emission cathode to allow concentrated sunlight to pass through and to provide mechanical protection, environmental isolation or anti-oxidation protection for the thermionic emission cathode. The inner light-transmitting protective layer is disposed on the side of the transparent anode away from the inter-electrode region and is located between the transparent anode and the solar heat-absorbing unit. It is used to isolate particles, gases or other heat-absorbing media in the solar heat-absorbing unit while ensuring the passage of transmitted light. The interelectrode region is used to provide space for the transport of electrons emitted from the cathode to the transparent anode; The window support and sealing structure is used to support and fix the thermionic emission cathode, the transparent anode and the outer light-transmitting protective layer, maintain the relative position and inter-electrode distance between the thermionic emission cathode and the transparent anode, and seal the inter-electrode area to maintain a preset vacuum, gas pressure or vapor environment.

7. The tower solar energy receiving system with an integrated thermionic power generation window according to claim 5, characterized in that, Multiple thermionic electron generating modules are sealed and connected to a sealing structure through window support; the inter-electrode regions of adjacent thermionic electron generating modules are interconnected through an inter-electrode connection channel, which is connected to a vacuum interface, and the vacuum interface is connected to a vacuum pump through a valve. More preferably, the thermionic emission cathode includes a light-transmitting substrate and a cathode film disposed on the side of the light-transmitting substrate facing the interelectrode region; the cathode film emits electrons into the interelectrode region under heating conditions and allows at least part of the incident light to pass through; More preferably, the cathode film is formed from one or more of semiconductor materials, metallic materials, metal borides, metal carbides, metal nitrides, carbon-based materials, low electron affinity materials, or doped materials or composite materials of the above materials; Most preferably, the semiconductor material includes one or more of silicon, germanium, gallium arsenide, indium phosphide, gallium nitride, indium gallium nitride, silicon carbide, diamond or its doped materials, alloy materials, and heterostructure materials; the metallic material includes one or more of tungsten, molybdenum, tantalum, rhenium, hafnium or their alloys; the metal borides include one or more of lanthanum hexaboride, cerium hexaboride, or other rare earth borides; and the carbon-based material includes one or more of graphene, few-layer graphene, carbon nanotube films, or doped diamond. More preferably, the outer light-transmitting protective layer is further provided with an anti-reflection layer or a spectral modulation layer to reduce the reflection loss of incident sunlight or to adjust the spectrum incident on the thermionic emission cathode; More preferably, the surface of the inner light-transmitting protective layer is further provided with an anti-reflection layer, a wear-resistant layer, an anti-pollution layer, or a spectral modulation layer to reduce transmitted light loss; More preferably, the inter-electrode region is at least one of a vacuum environment or a low-pressure medium environment containing alkali metal vapor.

8. The tower solar energy receiving system with an integrated thermionic power generation window according to any one of claims 1-7, characterized in that, The external circuit is connected to the cathode and anode of the thermionic power generation light-transmitting window; the external circuit includes wires and an electrical load adjustment module, which is used to adjust the output voltage, output current or output power of the thermionic power generation light-transmitting window; the electrical load adjustment module is an adjustable resistive load, an electronic load, a DC-DC converter circuit, an energy storage charging circuit or a combination thereof.

9. A method for operating a tower solar energy receiving system with an integrated thermionic power generation window as described in any one of claims 1-8, characterized in that, include: The heliostat field is used to reflect and focus sunlight onto the entrance port of the tower solar receiver; This allows concentrated sunlight to be incident onto the thermionic power generation light-transmitting window; The thermionic power generation transparent window selectively absorbs a portion of solar photons and outputs electrical energy. Specifically, by configuring the band gap, absorption coefficient, thin film thickness, or optical control layer of the cathode material, at least a portion of solar photons are absorbed by the cathode, generating thermionic emission, while the remaining sunlight passes through the thermionic power generation transparent window. Electrons in the cathode are emitted to the interelectrode region under the combined effects of light and high temperature and are collected by the transparent anode. The cathode and transparent anode are connected through an external circuit to form a current in the external circuit and output electrical energy to the load. The remaining solar spectrum that is not absorbed or reflected passes through the thermionic power generation window; The solar heat absorption unit inside the tower-type solar receiver is heated by transmitted sunlight.

10. The operation method of the tower solar energy receiving system with integrated thermionic power generation window according to claim 9, characterized in that, The operation control unit also includes a parameter acquisition component, which is connected to the external circuit of the thermionic power generation light-transmitting window, the heat absorption medium conveying device, and the heliostat field control device. Based on the operating status of the thermionic power generation light-transmitting window and the solar heat absorption unit, it coordinates and controls the power generation output and the high-temperature heat absorption process. The coordination and control process specifically includes: The parameter acquisition component acquires at least one of the following parameters: incident light intensity, temperature of the thermionic power generation light transmission window, output voltage of the thermionic power generation light transmission window, output current of the thermionic power generation light transmission window, transmitted light intensity, inlet temperature of the heat-absorbing medium, outlet temperature of the heat-absorbing medium, and flow rate of the heat-absorbing medium. The operation control unit pre-sets the allowable temperature range of the thermionic power generation light-transmitting window, the target outlet temperature range of the heat-absorbing medium, and the target electrical operating range of the thermionic power generation light-transmitting window; the allowable temperature range of the thermionic power generation light-transmitting window is determined based on the allowable operating temperature of at least one component among the cathode, transparent anode, transparent protective layer, support structure, and sealing structure; the target outlet temperature range of the heat-absorbing medium is determined based on the subsequent heat storage, power generation, or process heat requirements; the target electrical operating range is determined based on the output voltage-current characteristic or output power-voltage characteristic of the thermionic power generation light-transmitting window. When the temperature of the thermionic power generation light transmission window exceeds the upper limit of the allowable temperature range, the solar radiation flux received by the thermionic power generation light transmission window is reduced by changing the aiming point of the heliostat field, reducing the concentration intensity, or defocusing part of the heliostat field. The equivalent load of the external circuit can be adjusted according to the preset electrical characteristics of the thermionic power generation light transmission window to make it operate in the target electrical operating range and to help control the temperature of the thermionic power generation light transmission window. When the outlet temperature of the heat-absorbing medium is lower than the lower limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is reduced within the allowable flow range to prolong its heating time in the solar heat-absorbing unit; when the outlet temperature of the heat-absorbing medium is higher than the upper limit of the target outlet temperature range, the flow rate of the heat-absorbing medium is increased first; if the temperature requirements are still not met, some heliostats are deviated from the thermionic power generation light transmission window or are in a defocused state, and the aiming point of the heliostats is dispersed to reduce the local heat flux density and reduce the solar radiation power entering the solar heat-absorbing unit; Through the above control, the coordinated operation between thermionic power generation output, transmitted solar energy flow, and the high-temperature heat absorption and storage process of the solar heat absorption unit is achieved.

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