A heliostat night attitude regulation system and method for inhibiting frosting

Abstract

The present application relates to the technical field of solar thermal power generation, in particular to a heliostat night posture regulation system and method for inhibiting frosting. The present application comprises a power station weather station group for collecting temperature, humidity, wind speed and wind direction weather data in real time for calculating the amount of frosting; a mirror surface parameter collector group for collecting heliostat surface or frost layer temperature and emissivity data in real time; a weather forecast database for outputting solar radiation intensity, temperature, wind speed and wind direction data for predicting the second day's defrosting period; a data processor for collecting weather data and heliostat surface or frost layer temperature and emissivity data, and performing data analysis, comparison and discrimination; and a central control system for receiving the data analysis, comparison and discrimination results of the data processor. The present application realizes discrimination of whether the heliostat produces frosting, prediction of the amount of frosting and defrosting time, and further regulation of the heliostat night posture through real-time sensing of multi-source environmental parameters and mirror surface parameters.

Description

Technical Field

[0001] This invention relates to the field of solar thermal power generation technology, and in particular to a heliostat nighttime attitude control system and method for suppressing frost formation. Background Technology

[0002] Tower solar thermal power generation, as a large-scale, dispatchable clean energy technology, operates on the principle of precisely reflecting and concentrating sunlight onto a collector at the top of a tower using numerous heliostats. This generates high-temperature, high-pressure steam to drive a turbine and generate electricity. In this system, the reflection efficiency and concentration precision of the heliostats directly determine the energy conversion efficiency and power generation capacity of the entire power plant. However, in areas with large diurnal temperature variations or high humidity, frost easily forms on the heliostat surfaces at night. When the mirror surface temperature drops below the dew point and reaches freezing point, water vapor in the air condenses directly on the mirror surface, solidifying into a frost layer. This natural phenomenon poses a significant challenge to the operation of solar thermal power plants.

[0003] Frost buildup on the heliostat mirrors significantly reduces reflectivity, severely interfering with and scattering incident sunlight. This means that a large amount of solar radiation energy that should be reflected to the collector is wasted and cannot be effectively converted into heat, directly resulting in a loss of power generation. Furthermore, frost alters the micro-geometry of the heliostat surface, transforming it from an ideal smooth plane into a rough surface. This causes reflected light to deviate and fail to focus precisely on the collector at the top of the tower, resulting in a deterioration of the concentrated solar flux density distribution, further reducing the collector's thermal efficiency and potentially posing safety hazards.

[0004] The power station primarily relies on natural defrosting, which involves waiting for sunrise and then using sunlight to directly illuminate the frost layer on the heliostat surface or its relatively high-absorption back side. The heat generated through photothermal conversion raises the mirror surface temperature, melting the frost. However, the heliostat system is only put into operation after all the frost has melted, causing a delay in the power station's operation. This delay is directly proportional to the amount of frost buildup on the heliostat surface. Therefore, the industry urgently needs a proactive and effective method to reduce nighttime frost buildup on heliostat surfaces.

[0005] Currently, the heliostats in concentrated solar power (CSP) plants are primarily designed for wind resistance at night, meaning they are adjusted to a specific angle via a transmission mechanism to enhance stability during windy conditions. However, this nighttime heliostat control strategy does not yet consider adjusting the heliostats' nighttime placement orientation to suppress frost formation on the mirror surface, thus failing to improve the power plant's heat collection the following day. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a heliostat nighttime attitude control system and method for suppressing frost, which can dynamically adjust the heliostat field according to changes in environmental parameters to achieve active frost suppression, and control the heliostat equipment by analyzing the economics of the frost suppression strategy.

[0007] To achieve the above and other related objectives, the present invention provides a heliostat nighttime attitude control system for suppressing frost, comprising: a power station meteorological station group, a heliostat parameter acquisition group, a weather forecast database, a data processor, a central control system, and a heliostat controller; The power station's meteorological station group is used to collect real-time meteorological data such as temperature, humidity, wind speed, and wind direction for calculating frost amount; The mirror parameter acquisition group is used to collect real-time data on the surface temperature and emissivity of the heliostat or frost layer. The weather forecast database is used to output data on solar radiation intensity, temperature, wind speed, and wind direction for predicting the frost melt on the second day. The data processor is used to collect meteorological data and heliostat surface or frost layer temperature and emissivity data, and to perform data analysis, processing, comparison and discrimination. The data processor is connected to the power station meteorological station group, the heliostat parameter acquisition device group and the weather forecast database. A central control system is connected to the data processor, and the central control system is used to receive the data analysis, processing, comparison and discrimination results from the data processor. A heliostat controller, which is connected to the central control system; A full heliostat field, wherein each heliostat is equipped with a heliostat controller, which controls the transmission device of the heliostats, thereby adjusting the placement attitude of the heliostats in the full heliostat field, or adjusting the placement attitude of the heliostats in each area of ​​the full heliostat field separately.

[0008] In one embodiment of the present invention, the power station meteorological station group includes at least one power station meteorological station; the mirror parameter acquisition device group includes at least one mirror parameter acquisition device.

[0009] The present invention also provides a method for controlling the nighttime attitude of a heliostat to suppress frost, comprising the above-mentioned system for controlling the nighttime attitude of a heliostat to suppress frost, wherein the method for controlling the nighttime attitude of a heliostat to suppress frost includes: S1. Real-time acquisition of meteorological data such as temperature, humidity, wind speed, and wind direction for calculating frost amount, as well as heliostat surface or frost layer temperature and emissivity data; S2. Calculate the dew point temperature based on the air temperature and humidity, and compare the heliostat surface temperature with the dew point temperature. If the heliostat surface temperature is lower than the dew point temperature and 0°C, it is considered that frost has occurred, and step S3 is executed; otherwise, determine whether daytime conditions have been met. If yes, the control process ends; otherwise, return to step S1. S3. Calculate the amount of frost on the mirror surface when the mainstream airflow direction and the current heliostat angle are not significantly changed over a period of time. S4. Calculate the amount of frost on the heliostat after adjusting the angle between the mainstream airflow direction and the heliostat surface during this period, and obtain the amount of frost reduction after adjusting the heliostat attitude. S5. Based on the weather forecast database, predict the total solar radiation, air temperature, wind speed, and wind direction meteorological data during the frost-free period on the morning of the second day, and calculate the frost-free time shortened by reducing frost formation after adjusting the heliostat's attitude according to the heliostat's own characteristics. S6. Obtain the DNI value for the corresponding time period in the morning from meteorological data or typical meteorological year data, and calculate the increased revenue of the power plant by shortening the defrosting time based on the heat collection efficiency of the heat collection system, power generation strategy, and grid connection price. S7. Calculate the electricity consumed in adjusting the heliostat's attitude and calculate the power plant's reduced revenue based on nighttime electricity prices; S8. When the increased revenue of the power station due to shortening the defrosting time is greater than the decreased revenue due to adjusting the heliostat attitude, the heliostat attitude needs to be adjusted, and step S9 is performed sequentially; otherwise, it is determined whether the daytime conditions are met. If so, the control process ends; otherwise, return to step S1. S9. The data processor transmits the adjustment signal to the central control system, which adjusts the heliostat's placement attitude through the heliostat controller and determines whether daytime conditions are met. If so, the control process ends; otherwise, it returns to step S1.

[0010] In one embodiment of the present invention, step S2, which involves calculating the dew point temperature based on air temperature and humidity, comparing the heliostat surface temperature with the dew point temperature, and determining that frost has occurred when the heliostat surface temperature is lower than both the dew point temperature and 0°C, includes: Dew point temperature calculation formula based on Magnus-Tetens approximation ,in , , , For air temperature, The relative humidity of the air, when the surface temperature of the heliostat and At this time, frost will form on the surface of the heliostat; when the surface temperature of the heliostat... and At that time, condensation will occur on the surface of the heliostat.

[0011] In one embodiment of the present invention, the calculation of the amount of frost on the mirror surface during a period in which future meteorological parameters do not change significantly includes: It is expected that in the near future With no significant changes in internal environmental parameters, according to the law of conservation of mass, the amount of frost per unit area of ​​the heliostat is expressed as: ,in, The mass flux of water vapor diffusing from the air to the mirror surface, i.e., the rate of increase in the mass of the frost layer, is expressed as: ,in, The convective mass transfer coefficient, The density of water vapor in the mainstream air. The temperature of the frost layer or the surface of the heliostat. The saturated water vapor density at a given temperature is used to correlate heat and mass transfer via the Lewis relation. ,in, For Lewis numbers, for air-water vapor systems, ,therefore, , The convective heat transfer coefficient is... The specific heat capacity of moist air at constant pressure. ,in, , , Based on mainstream air temperature Mainstream relative humidity Surface temperature And obtained in conjunction with the humid air property table, and The temperature and humidity data were obtained from the temperature and humidity sensors at the power station's weather station. Obtained using infrared thermometry. mainstream airflow velocity The angle between the mainstream airflow and the heliostat The function, i.e. The function is established through CFD simulation or experimentation, where... The anemometer readings were obtained from the power station's weather station. The results were obtained from the attitude of the wind vane and heliostat at the power station's meteorological station.

[0012] In one embodiment of the present invention, step S4, which involves calculating the amount of frost on the heliostat surface after adjusting the angle between the mainstream airflow direction and the heliostat surface during that period, and obtaining the reduction in frost amount after adjusting the heliostat attitude, includes: By calculating the angle between the mainstream airflow direction and the heliostat surface... Adjusted to The difference in frost amount between the two values ​​is used to obtain the reduction in frost amount after adjusting the heliostat's attitude. ,Right now: .

[0013] In one embodiment of the present invention, step S5, which involves predicting the total solar radiation, air temperature, wind speed, and wind direction meteorological data during the frost-melting period on the morning of the second day based on the weather forecast database, and calculating the frost-melting time shortened by reducing frost formation after adjusting the heliostat's attitude according to the heliostat's own characteristics, includes: Calculate defrost time First, calculate the net heat flux power acting on a unit surface area of ​​the heliostat. Specifically: , in, This is the net heat flow power used to melt the frost layer; Solar radiation power. , For the heliostats tracking a tower-type solar thermal power plant, the back side faces the sun during the defrost period, which is the angle of solar incidence. , The heliostat's back radiation absorptivity; The long-wave radiation power absorbed by the frost layer. This represents the power radiated outwards by the frost layer. , The surface emissivity of the frost layer, It is the Stefan-Boltzmann constant; For convective heat dissipation power, Surface temperature of frost layer during melting stage , Related to wind speed and direction, the total solar radiation during the frost melt on the following morning was obtained by combining meteorological data from the power station with typical meteorological year data. , , and wind direction, , The result is calculated from real-time instrument measurements or fixed values ​​measured in the laboratory. ; When the ambient temperature is close to 0℃ during the morning defrost period, or when the convective heat dissipation power, ambient radiative heat transfer power, and frost layer radiative power are relatively low, At this time, the heat from which the frost melts comes approximately from solar radiation. The shortened morning frost-melting time after adjusting the heliostat's attitude was calculated:

[0014] in, This is the latent heat of melting of the frost layer.

[0015] In one embodiment of the present invention, step S6 involves obtaining the DNI value for the corresponding time period in the morning from meteorological data or typical meteorological year data, and calculating the increased revenue of the power plant due to shortening the defrosting time based on the thermal efficiency of the thermal collection system, power generation strategy, and grid connection price. Due to the reduced morning defrosting time, the heliostats of the solar thermal power plant can be put into operation earlier, which is estimated to shorten the defrosting time. Increased heat collection ,in, To determine the effective reflective area of ​​the operational mirror field, To determine the heat collection efficiency of the solar thermal system, data for the corresponding morning time period is obtained from meteorological data or typical meteorological year data. Value, calculate the increased revenue of the power plant: , in, To shorten defrosting time The increased power generation To improve the power plant's thermoelectric conversion efficiency, the feed-in tariff is determined based on the power plant's power generation strategy. .

[0016] In one embodiment of the present invention, the calculation of the electricity consumed in adjusting the heliostat attitude in step S7, and the calculation of the reduced revenue of the power station based on the nighttime electricity price, includes: Calculate the heliostat attitude at night from Adjusted to Reduced power plant revenue: , in, To adjust the heliostat's orientation from Adjusted to Required electricity This refers to nighttime electricity pricing.

[0017] In one embodiment of the present invention, when the increased revenue of the power station due to shortening the defrosting time in step S8 is greater than the decreased revenue due to adjusting the heliostat attitude, heliostat attitude adjustment is required, including: when At that time, the heliostat attitude adjustment action is performed, and the heliostat is adjusted. Adjusted to .

[0018] As described above, the heliostat nighttime attitude control system and method for suppressing frost according to the present invention have the following beneficial effects: (1) The present invention provides a nighttime attitude control system and method for suppressing frost on a heliostat. By sensing multi-source environmental parameters (such as ambient temperature, humidity, wind speed, wind direction, etc.) and mirror parameters (such as temperature, emissivity, etc.) in real time, the system can determine whether frost will form on the heliostat and predict the amount of frost and the defrosting time.

[0019] (2) The present invention provides a nighttime attitude control system and method for suppressing frost on a heliostat. Because it can predict and respond quickly, the system can choose to carry out preventive frost suppression at night, which can enable the heliostat to be put into operation 30-120 minutes earlier in the morning, thereby increasing the power station's heat collection and annual power generation.

[0020] (3) The present invention provides a nighttime attitude control system and method for suppressing frost formation of a heliostat. It establishes the relationship between the amount of frost formation, defrosting time, power plant revenue and the nighttime placement attitude of the heliostat (the angle between the mainstream airflow direction and the heliostat surface). Through economic comparison, the placement attitude of the heliostat is adaptively adjusted, thereby reducing the formation of frost on the surface of the heliostat and achieving active suppression of frost. Attached Figure Description

[0021] Figure 1 A schematic diagram of a nighttime attitude control system for suppressing frost provided in one embodiment of this application; Figure 2 A schematic diagram of a heliostat nighttime attitude control system for suppressing frost, provided in another embodiment of this application; Figure 3 A flowchart illustrating a method for controlling the nighttime attitude of a heliostat to suppress frost formation, provided in an embodiment of this application; Figure 4 This is a schematic diagram of heliostat attitude adjustment, illustrating a nighttime attitude control method for suppressing frost provided in an embodiment of this application. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0023] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0024] Terms such as "first" or "second" may be used to describe various components, but these components are not limited by the terms described above. The terms described above are used to distinguish one component from another; for example, without departing from the scope of the concept according to this disclosure, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component.

[0025] Furthermore, "connected / linked" indicates that one component is directly electrically connected to another component or indirectly electrically connected through another component. Unless otherwise explicitly stated in the sentence, the singular form may include the plural form. Additionally, the terms "comprising / including" or "containing / including" as used in this specification indicate the presence or addition of one or more components, steps, operations, and elements. Specific structural or functional descriptions of examples of embodiments of the concepts disclosed in this specification are merely illustrative to describe examples of embodiments of the concepts, and examples of embodiments of the concepts can be implemented in various forms, but these descriptions are not limited to the examples of embodiments described in this specification.

[0026] Based on the concept, various modifications and changes can be applied to examples of embodiments, such that examples of embodiments will be illustrated in the accompanying drawings and described in the specification. However, examples of embodiments based on the concept are not limited to specific embodiments, but include all changes, equivalents, or substitutions included within the spirit and scope of this disclosure.

[0027] It should be understood that when describing an element as "connected" or "linked" to another element, the element may be directly connected or linked to the other element, or it may be connected or linked to the other element via a third element. Conversely, it should be understood that when an element is described as "directly connected to" or "directly linked to" another element, no other element is placed between them. Other expressions describing relationships between components (i.e., "between" and "directly between" or "adjacent to" and "directly adjacent to") need to be interpreted in the same way.

[0028] The terminology used in this specification is for the purpose of describing specific examples of implementations only and is not intended to limit this disclosure. The singular form may include the plural form unless there is an explicit contrary meaning in the context. It should be understood in this specification that the terms "comprising" or "having" indicate the presence of the features, quantities, steps, operations, components, parts, or combinations thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, quantities, steps, operations, components, parts, or combinations thereof.

[0029] Unless otherwise defined, all terms used herein (including technical or scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art. If a term is not clearly defined in a common dictionary in this specification, it shall be interpreted as having the same meaning as in the context of the relevant art, and not as an ideal or overly formal meaning.

[0030] Descriptions of known components and processing techniques may be omitted to avoid unnecessarily obscuring the embodiments of this disclosure.

[0031] Throughout this specification, the same reference numerals refer to the same elements. Therefore, even if a reference numeral is not mentioned or described with reference to one drawing, it may be mentioned or described with reference to another drawing. Furthermore, even if a reference numeral is not shown in one drawing, it may be mentioned or described with reference to another drawing.

[0032] Additionally, the logic level of a signal may be different from or opposite to the logic level described. For example, a signal described as having a logic "high" level may optionally have a logic "low" level, and a signal described as having a logic "low" level may optionally have a logic "high" level.

[0033] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0034] Currently, (1) nighttime frost formation on heliostats is affected by multiple factors such as temperature, humidity, wind speed, wind direction, and surface characteristics of the heliostats, and there is a lack of methods for predicting the amount of surface frost and defrosting time based on environmental parameters and heliostat characteristics; (2) current solar thermal power plants lack methods to suppress nighttime frost formation on the surface of heliostats, and cannot dynamically control the frost formation on the surface of heliostats under specific meteorological conditions. Therefore, this invention provides a nighttime attitude control system and method for suppressing frost formation on heliostats. This invention: (1) By real-time sensing of multi-source environmental parameters (such as ambient temperature, humidity, wind speed, wind direction, etc.) and mirror parameters (such as temperature, emissivity, etc.), the system can determine whether the heliostat will frost, and predict the amount of frost and the defrosting time; (2) Establish the relationship between the amount of frost, defrosting time, power plant revenue and the nighttime placement posture of the heliostat (the angle between the mainstream airflow direction and the heliostat surface); (3) Adaptively adjust the placement posture of the heliostat for specific meteorological conditions, thereby reducing the formation of frost on the surface of the heliostat and achieving active suppression of frost.

[0035] Please see Figure 1 , Figure 2 , Figure 1 A schematic diagram of a nighttime attitude control system for suppressing frost provided in one embodiment of this application; Figure 2 This is a schematic diagram of a nighttime attitude control system for suppressing frost, provided as another embodiment of this application. The present invention provides a nighttime attitude control system for suppressing frost on a heliostat, comprising: a power plant meteorological station group 1, a heliostat parameter acquisition unit group 2, a weather forecast database 3, a data processor 4, a central control system 5, and a heliostat controller 6; the power plant meteorological station group 1 is used to collect real-time meteorological data such as temperature, humidity, wind speed, and wind direction for calculating frost amount; the heliostat parameter acquisition unit group 2 is used to collect real-time data on the surface temperature and emissivity of the heliostat or frost layer; the weather forecast database 3 is used to output data on solar radiation intensity, temperature, wind speed, and wind direction for predicting the frost melt period on the second day; the data processor 4 is used to collect meteorological data and the surface temperature and emissivity of the heliostat or frost layer. The data processor 4 is connected to the power station meteorological station group 1, the mirror parameter acquisition group 2, and the weather forecast database 3. The central control system 5 is connected to the data processor 4 and is used to receive the data analysis, processing, comparison, and discrimination results from the data processor 4. The heliostat controller 6 is connected to the central control system 5. Each heliostat in the entire heliostat field 7 is equipped with the heliostat controller 6. The heliostat controller 6 controls the transmission device of the heliostat, thereby adjusting the placement posture of the heliostats in the entire heliostat field 7, or adjusting the placement posture of the heliostats in each area of ​​the entire heliostat field 7 separately.

[0036] In one embodiment of the present invention, a heliostat nighttime attitude control system for suppressing frost includes a power station meteorological station group 1, a heliostat parameter acquisition device group 2, a weather forecast database 3, a data processor 4, a central control system 5, and a heliostat controller 6. The power station meteorological station group 1 collects meteorological data such as temperature, humidity, wind speed, and wind direction in real time for calculating frost amount; the heliostat parameter acquisition device group 2 collects data such as surface temperature and emissivity of the heliostat or frost layer in real time; the weather forecast database 3 outputs data such as solar radiation intensity, temperature, wind speed, and wind direction during the frost melt period on the second day; the power station meteorological station group 1, the heliostat parameter acquisition device group 2, and the weather forecast database 3 are all connected to the data processor 4; the power station meteorological station group 1 consists of one or more power station meteorological stations; the heliostat parameter acquisition device group 2 consists of one or more heliostat parameter acquisition devices; The data processor 4 is used to collect meteorological data and mirror data, and can perform data analysis and processing, including dew point temperature calculation, frost amount calculation, defrosting time calculation, power plant revenue calculation, etc., and can perform comparison and discrimination. The data processor 4 is connected to the central control system 5 and sends data processing, comparison and discrimination signals to the central control system 5. The central control system 5 is connected to the heliostat controller 6 and controls the heliostat's transmission device to adjust the placement posture of the heliostats in the entire heliostat field 7, or adjust the placement posture of the heliostats in each area of ​​the heliostat field 7 separately.

[0037] Please see Figure 3 , Figure 3 This invention provides a flowchart of a method for controlling the nighttime attitude of a heliostat to suppress frost, as provided in an embodiment of this application. The invention also provides a method for controlling the nighttime attitude of a heliostat to suppress frost, comprising the aforementioned system for controlling the nighttime attitude of a heliostat to suppress frost, wherein the method includes: S1. Real-time collection of meteorological data such as temperature, humidity, wind speed, and wind direction, as well as data such as the surface temperature and emissivity of the heliostat or frost layer; S2. Calculate the dew point temperature based on the air temperature and humidity, and compare the heliostat surface temperature with the dew point temperature. If the heliostat surface temperature is lower than the dew point temperature and 0°C, it is considered that frost has occurred, and step S3 is executed sequentially; otherwise, determine whether daytime conditions have been met. If yes, end the control process; otherwise, return to step S1. S3. Calculate the amount of frost on the mirror surface when the mainstream airflow direction and the current heliostat angle are not significantly changed over a period of time. S4. Calculate the amount of frost on the heliostat after adjusting the angle between the mainstream airflow direction and the heliostat surface during this period, and obtain the amount of frost reduction after adjusting the heliostat attitude. S5. Based on the weather forecast database, predict meteorological data such as total solar radiation, air temperature, wind speed, and wind direction during the frost-free period on the morning of the second day, and calculate the frost-free time shortened by reducing frost formation after adjusting the heliostat's attitude, based on the heliostat's own characteristics. S6. Obtain the DNI value for the corresponding time period in the morning from meteorological data or typical meteorological year data, and calculate the increased revenue of the power plant by shortening the defrosting time based on the heat collection efficiency of the heat collection system, power generation strategy, and grid connection price. S7. Calculate the electricity consumed in adjusting the heliostat's attitude and calculate the power plant's reduced revenue based on nighttime electricity prices; S8. When the increased revenue of the power station due to shortening the defrosting time is greater than the decreased revenue due to adjusting the heliostat attitude, it is considered that heliostat attitude adjustment is necessary, and step S9 is performed sequentially; otherwise, it is determined whether the daytime conditions are met. If so, the control process ends; otherwise, it returns to step S1. S9. The data processor transmits the adjustment signal to the central control system, which adjusts the heliostat's placement attitude through the heliostat controller and determines whether daytime conditions are met. If so, the control process ends; otherwise, it returns to step S1.

[0038] Specifically, in step S2, the dew point temperature is calculated based on the air temperature and humidity. The heliostat surface temperature is then compared with the dew point temperature. When the heliostat surface temperature is lower than both the dew point temperature and 0°C, frost is considered to have occurred. This includes: Dew point temperature calculation formula based on Magnus-Tetens approximation ,in , , , For air temperature, The relative humidity of the air, when the surface temperature of the heliostat and At this time, frost will form on the surface of the heliostat; when the surface temperature of the heliostat... and At that time, condensation will occur on the surface of the heliostat.

[0039] Specifically, step S3, calculating the amount of frost on the heliostat surface during a period when future meteorological parameters do not change significantly, includes: It is expected that in the near future With no significant changes in internal environmental parameters, according to the law of conservation of mass, the amount of frost per unit area of ​​the heliostat is expressed as: ,in, The mass flux of water vapor diffusing from the air to the mirror surface, i.e., the rate of increase in the mass of the frost layer, is expressed as: ,in, The convective mass transfer coefficient, The density of water vapor in the mainstream air. The temperature of the frost layer or the surface of the heliostat. The saturated water vapor density at a given temperature is used to correlate heat and mass transfer via the Lewis relation. ,in, For Lewis numbers, for air-water vapor systems, ,therefore, , The convective heat transfer coefficient is... The specific heat capacity of moist air at constant pressure. ,in, , , Based on mainstream air temperature Mainstream relative humidity Surface temperature And obtained in conjunction with the humid air property table, and The temperature and humidity data were obtained from the temperature and humidity sensors at the power station's weather station. Obtained using infrared thermometry. Mainstream airflow speed (wind speed) The angle between the mainstream airflow and the heliostat The function, i.e. The function is established through CFD simulation or experimentation, where... The anemometer readings were obtained from the power station's weather station. The results were obtained from the attitude of the wind vane and heliostat at the power station's meteorological station.

[0040] Specifically, step S4 involves calculating the amount of frost on the heliostat surface after adjusting the angle between the mainstream airflow direction and the heliostat surface during this period, and obtaining the reduction in frost after adjusting the heliostat's attitude, including: By calculating the angle between the mainstream airflow direction and the heliostat surface... Adjusted to The difference in frost amount between the two values ​​is used to obtain the reduction in frost amount after adjusting the heliostat's attitude. ,Right now: .

[0041] Specifically, step S5 involves predicting the total solar radiation, air temperature, wind speed, and wind direction meteorological data during the frost-free period on the morning of the second day based on the weather forecast database 3, and calculating the frost-free time shortened by reducing frost formation after adjusting the heliostat's attitude, based on the heliostat's own characteristics. Calculate defrost time First, calculate the net heat flux power acting on a unit surface area of ​​the heliostat. Specifically: , in, This is the net heat flow power used to melt the frost layer; Solar radiation power. , For the heliostats tracking a tower-type solar thermal power plant, the back side faces the sun during the defrost period, which is the angle of solar incidence. , The heliostat's back radiation absorptivity; The long-wave radiation power absorbed by the frost layer. This represents the power radiated outwards by the frost layer. , The surface emissivity of the frost layer, It is the Stefan-Boltzmann constant; For convective heat dissipation power, Surface temperature of frost layer during melting stage , Related to wind speed and direction, the total solar radiation during the frost melt on the following morning was obtained by combining meteorological data from the power station with typical meteorological year data. , , and wind direction, , The result is calculated from real-time instrument measurements or fixed values ​​measured in the laboratory. ; When the ambient temperature is close to 0℃ during the morning defrost period, or when the convective heat dissipation power, ambient radiative heat transfer power, and frost layer radiative power are relatively low, At this time, the heat from which the frost melts comes approximately from solar radiation. The shortened morning frost-melting time after adjusting the heliostat's attitude was calculated:

[0042] in, This is the latent heat of melting of the frost layer.

[0043] Specifically, in step S6, the DNI value for the corresponding morning period is obtained from meteorological data or typical meteorological year data. Based on the thermal efficiency of the solar collector system, power generation strategy, and grid connection price, the increased revenue of the power plant due to shortening the defrosting time is calculated, including: Due to the reduced morning defrosting time, the heliostats of the solar thermal power plant can be put into operation earlier, which is estimated to shorten the defrosting time. Increased heat collection ,in, To determine the effective reflective area of ​​the operational mirror field, To determine the heat collection efficiency of the solar thermal system, data for the corresponding morning time period is obtained from meteorological data or typical meteorological year data. Value, calculate the increased revenue of the power plant: , in, To shorten defrosting time The increased power generation To improve the power plant's thermoelectric conversion efficiency, the feed-in tariff is determined based on the power plant's power generation strategy. .

[0044] Specifically, step S7 calculates the electricity consumed in adjusting the heliostat's attitude, and calculates the power plant's reduced revenue based on nighttime electricity prices, including: Calculate the heliostat attitude at night from Adjusted to Reduced power plant revenue: , in, To adjust the heliostat's orientation from Adjusted to Required electricity This refers to nighttime electricity pricing.

[0045] Please see Figure 4 , Figure 4 This is a schematic diagram of heliostat attitude adjustment in a heliostat nighttime attitude control method for suppressing frost provided in an embodiment of this application. Specifically, in step S8, when the increased revenue of the power plant due to shortening the defrosting time exceeds the decreased revenue due to heliostat attitude adjustment, heliostat attitude adjustment is required, including: when At that time, the heliostat attitude adjustment action is performed, and the heliostat is adjusted. Adjusted to .

[0046] In one embodiment of the invention, based on meteorological data from a frosty day, the nighttime temperature was approximately -7.9°C, and the relative humidity was 60%RH. Frosting would occur when the surface temperature of the heliostat was lower than the air temperature. The initial azimuth and horizontal angles of the heliostat were 234° and 45° respectively, the nighttime wind direction was 280°, and the wind speed was 1.4 m / s. The frost was expected to last approximately 7 hours, during which the wind speed and direction remained relatively stable. The predicted total radiation during the frost-melting period the following morning was 550. If the heliostat azimuth angle is adjusted to 100° (horizontal angle unchanged), the defrosting time is expected to be shortened by approximately 12 minutes. For a solar thermal power plant with a heliostat field area of ​​1 million square meters, this could increase power generation by approximately 24,000 kilowatt-hours. If this power generation occurs during peak electricity consumption periods, after deducting the electricity required for nighttime heliostat attitude adjustment, the power plant's revenue is expected to increase by approximately 14,000 yuan. Therefore, heliostat attitude adjustment is feasible. Based on the above analysis, the data processor transmits the relevant data and judgment results to the central control system. The central control system then sends a command to the heliostat controller to adjust the heliostat from its initial attitude (azimuth / horizontal angle of 234° / 45°) to the target attitude (100° / 45°).

[0047] In summary, the present invention provides a heliostat nighttime attitude control system and method for suppressing frost, which uses real-time sensing of multi-source environmental parameters (such as ambient temperature, humidity, wind speed, wind direction, etc.) and mirror parameters (such as temperature, emissivity, etc.) to enable the system to determine whether frost has formed on the heliostat and to predict the amount of frost and the defrosting time.

[0048] This invention also proposes an electronic device comprising a processor and a memory. The memory stores program instructions, and the processor executes these instructions to implement the aforementioned method for controlling the attitude of a heliostat at night to suppress frost formation. The processor can be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it can also be a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The memory may include Random Access Memory (RAM) and may also include Non-Volatile Memory, such as at least one disk storage device. The memory can also be an internal memory of the Random Access Memory (RAM) type. The processor and memory can be integrated into one or more independent circuits or hardware, such as an Application Specific Integrated Circuit (ASIC). It should be noted that when the computer program in the aforementioned memory is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, an electronic device, or a network device, etc.) to execute all or part of the steps of the methods of the various embodiments of the present invention.

[0049] This invention also proposes a computer-readable storage medium storing computer instructions for instructing the computer to execute the aforementioned method for controlling the attitude of a heliostat at night to suppress frost formation. The computer-readable storage medium can be an electronic medium, magnetic medium, optical medium, electromagnetic medium, infrared medium, or a semiconductor system or propagation medium. The computer-readable storage medium may also include semiconductor or solid-state memory, magnetic tape, removable computer disk, random access memory (RAM), read-only memory (ROM), hard disk, and optical disc. Optical discs may include optical disc-read-only memory (CD-ROM), optical disc-read / write (CD-RW), and DVD.

[0050] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A heliostat nighttime attitude control system for suppressing frost formation, characterized in that, include: The power station meteorological station group (1), the mirror parameter acquisition group (2), the weather forecast database (3), the data processor (4), the central control system (5), and the heliostat controller (6); The meteorological station group (1) of the power station is used to collect meteorological data such as temperature, humidity, wind speed and wind direction in real time for calculating the amount of frost. The mirror parameter acquisition group (2) is used to collect real-time data on the surface temperature and emissivity of the heliostat or frost layer. The weather forecast database (3) is used to output data on solar radiation intensity, temperature, wind speed, and wind direction for predicting the frost melt on the second day. The data processor (4) is used to collect meteorological data and surface or frost layer temperature and emissivity data of the heliostat, and to perform data analysis, comparison and discrimination. The data processor (4) is connected to the power station meteorological station group (1), the mirror parameter acquisition device group (2) and the weather forecast database (3). The central control system (5) is connected to the data processor (4). The central control system (5) is used to receive the data analysis, processing, comparison and discrimination results of the data processor (4). Heliostat controller (6), which is connected to the central control system (5); The entire heliostat field (7) is equipped with a heliostat controller (6) for each heliostat. The heliostat controller (6) controls the transmission device of the heliostat, thereby adjusting the placement posture of the heliostats in the entire heliostat field (7) or adjusting the placement posture of the heliostats in each area of ​​the entire heliostat field (7) separately.

2. The heliostat nighttime attitude control system for suppressing frost according to claim 1, characterized in that: The power station meteorological station group (1) includes at least one power station meteorological station; the mirror parameter acquisition device group (2) includes at least one mirror parameter acquisition device.

3. A method for controlling the nighttime attitude of a heliostat to suppress frost formation, characterized in that, The heliostat nighttime attitude control system for suppressing frost as described in claim 1 or 2, wherein the method for suppressing frost during nighttime operation of the heliostat includes: S1. Real-time acquisition of meteorological data such as temperature, humidity, wind speed, and wind direction for calculating frost amount, as well as heliostat surface or frost layer temperature and emissivity data; S2. Calculate the dew point temperature based on the air temperature and humidity, and compare the heliostat surface temperature with the dew point temperature. If the heliostat surface temperature is lower than the dew point temperature and 0°C, it is considered that frost has occurred, and step S3 is executed; otherwise, determine whether daytime conditions have been met. If yes, the control process ends; otherwise, return to step S1. S3. Calculate the amount of frost on the mirror surface when the mainstream airflow direction and the current heliostat angle are not significantly changed over a period of time. S4. Calculate the amount of frost on the heliostat after adjusting the angle between the mainstream airflow direction and the heliostat surface during this period, and obtain the amount of frost reduction after adjusting the heliostat attitude. S5. Based on the weather forecast database (3), predict the total solar radiation, air temperature, wind speed, and wind direction meteorological data during the frost-free period on the morning of the second day, and calculate the frost-free time shortened by reducing frost formation after adjusting the attitude of the heliostat according to its own characteristics. S6. Obtain the DNI value for the corresponding time period in the morning from meteorological data or typical meteorological year data, and calculate the increased revenue of the power plant by shortening the defrosting time based on the heat collection efficiency of the heat collection system, power generation strategy, and grid connection price. S7. Calculate the electricity consumed in adjusting the heliostat's attitude and calculate the power plant's reduced revenue based on nighttime electricity prices; S8. When the increased revenue of the power station due to shortening the defrosting time is greater than the decreased revenue due to adjusting the heliostat attitude, the heliostat attitude needs to be adjusted, and step S9 is performed sequentially; otherwise, it is determined whether the daytime conditions are met. If so, the control process ends; otherwise, return to step S1. S9. The data processor (4) transmits the adjustment signal to the central control system (5), and through the heliostat controller (6), adjusts the heliostat placement posture and determines whether the daytime conditions are met. If so, the control process ends; otherwise, it returns to step S1.

4. The method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 3, characterized in that, Step S2 involves calculating the dew point temperature based on air temperature and humidity, comparing the heliostat surface temperature with the dew point temperature, and determining that frost has occurred when the heliostat surface temperature is below both the dew point temperature and 0°C. This includes: Dew point temperature calculation formula based on Magnus-Tetens approximation ,in , , , For air temperature, The relative humidity of the air, when the surface temperature and At this time, frost will form on the surface of the heliostat; if frost has already formed on the heliostat, This refers to the surface temperature of the frost layer; in cases where no frost has formed, This refers to the surface temperature of the heliostat mirror; when the surface temperature... and At that time, condensation will occur on the surface of the heliostat.

5. The method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 4, characterized in that, Step S3 calculates the amount of frost on the heliostat surface when the mainstream airflow direction forms an angle with the current heliostat surface over a period of time during which future meteorological parameters do not change significantly. This includes: It is expected that in the near future With no significant changes in internal environmental parameters, according to the law of conservation of mass, the amount of frost per unit area of ​​the heliostat is expressed as: ,in, The mass flux of water vapor diffusing from the air to the mirror surface, i.e., the rate of increase in the mass of the frost layer, is expressed as: ,in, The convective mass transfer coefficient, The density of water vapor in the mainstream air. Surface temperature The saturated water vapor density at a given temperature is used to correlate heat and mass transfer via the Lewis relation. ,in, For Lewis numbers, for air-water vapor systems, ,therefore, , The convective heat transfer coefficient is... The specific heat capacity of moist air at constant pressure. ,in, , , Based on mainstream air temperature Mainstream relative humidity Surface temperature And obtained in conjunction with the humid air property table, and The temperature and humidity data were obtained from the temperature and humidity sensors at the power station's weather station. Obtained using infrared thermometry. mainstream airflow velocity The angle between the mainstream airflow and the heliostat The function, i.e. The function is established through CFD simulation or experimentation, where... The anemometer readings were obtained from the power station's weather station. The results were obtained from the attitude of the wind vane and heliostat at the power station's meteorological station.

6. The method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 5, characterized in that, Step S4 involves calculating the amount of frost on the heliostat surface after adjusting the angle between the mainstream airflow direction and the heliostat surface during this period, and obtaining the reduction in frost after adjusting the heliostat's attitude, including: By calculating the angle between the mainstream airflow direction and the heliostat surface... Adjusted to The difference in frost amount between the two values ​​is used to obtain the reduction in frost amount after adjusting the heliostat's attitude. ,Right now: 。 7. A method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 6, characterized in that, Step S5 involves predicting the total solar radiation, air temperature, wind speed, and wind direction meteorological data during the frost melt on the morning of the second day based on the weather forecast database (3), and calculating the frost melt time shortened by reducing frost formation after adjusting the heliostat's attitude, based on the heliostat's own characteristics. Calculate defrost time First, calculate the net heat flux power acting on a unit surface area of ​​the heliostat. Specifically: ， in, This is the net heat flow power used to melt the frost layer; Solar radiation power. , For the heliostats tracking a tower-type solar thermal power plant, the back side faces the sun during the defrost period, which is the angle of solar incidence. , The heliostat's back radiation absorptivity; The long-wave radiation power absorbed by the frost layer. This represents the power radiated outwards by the frost layer. , The surface emissivity of the frost layer, It is the Stefan-Boltzmann constant; For convective heat dissipation power, Surface temperature , Related to wind speed and direction, the total solar radiation during the frost melt on the following morning was obtained by combining meteorological data from the power station with typical meteorological year data. , , and wind direction, , The result is calculated from real-time instrument measurements or fixed values ​​measured in the laboratory. ; The shortened morning frost-melting time after adjusting the heliostat's attitude was calculated: in, This is the latent heat of melting of the frost layer.

8. A method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 7, characterized in that, Step S6 involves obtaining the DNI value for the corresponding morning period from meteorological data or typical meteorological year data, and calculating the increased revenue of the power plant due to shortening the defrosting time based on the thermal efficiency of the solar collector system, power generation strategy, and grid connection price. This includes: Due to the reduced morning defrosting time, the heliostats of the solar thermal power plant can be put into operation earlier, which is estimated to shorten the defrosting time. Increased heat collection ,in, To determine the effective reflective area of ​​the operational mirror field, To determine the heat collection efficiency of the solar thermal system, data for the corresponding morning time period is obtained from meteorological data or typical meteorological year data. Value, calculate the increased revenue of the power plant: , in, To shorten defrosting time The increased power generation To improve the power plant's thermoelectric conversion efficiency, the feed-in tariff is determined based on the power plant's power generation strategy. .

9. A method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 8, characterized in that, Step S7 calculates the electricity consumed in adjusting the heliostat's attitude, and calculates the power plant's reduced revenue based on nighttime electricity prices, including: Calculate the heliostat attitude at night from Adjusted to Reduced power plant revenue: ， in, To adjust the heliostat's orientation from Adjusted to Required electricity This refers to nighttime electricity pricing.

10. A method for controlling the nighttime attitude of a heliostat to suppress frost according to claim 9, characterized in that, In step S8, when the increased revenue from shortening the defrosting time exceeds the decreased revenue from adjusting the heliostat attitude, heliostat attitude adjustment is required, including: when At that time, the heliostat attitude adjustment action is performed, and the heliostat is adjusted. Adjusted to .

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