Heat absorber and operation method of heat absorber

Abstract

The present invention relates to the field of solar thermal power generation, and discloses a heat absorber and a heat absorber operation method, wherein temperature regulation and physical protection are performed by adding a thermochemical protection mechanism. The heat absorber comprises: a heat absorbing tube, in which a molten salt working medium is arranged; a protection mechanism, which is arranged on the outside of the heat absorbing tube; a thermochemical energy storage material is arranged in the protection mechanism, and the protection mechanism is arranged in contact with the heat absorbing tube; when the temperature of the heat absorbing tube is greater than a first preset temperature, the thermochemical energy storage material undergoes a reduction reaction to absorb heat, thereby lowering the temperature of the heat absorbing tube; when the temperature of the heat absorbing tube is less than a second preset temperature, the thermochemical energy storage material undergoes an oxidation reaction to release heat, thereby raising the temperature of the heat absorbing tube; there are multiple heat absorbing tubes, and the multiple heat absorbing tubes are arranged in sequence around the inner surface of the protection mechanism. Adding a thermochemical protection mechanism on the outside of the heat absorber can not only avoid physical damage to the heat absorbing tube, but also stabilize the temperature of the heat absorbing tube, thereby improving the safety of use and extending the service life of the heat absorber.

Description

Technical Field

[0001] The invention relates to the field of solar thermal power generation and discloses a heat absorber and an operating method of the heat absorber, which can spontaneously adjust the temperature of the heat absorber and extend the service life of the heat absorber. Background Art

[0002] Solar power generation technology is an effective means to alleviate the energy crisis and has broad application prospects. Solar power generation technology is mainly divided into two types: solar thermal power generation and photovoltaic power generation. Solar thermal power generation can reduce peak loads and fill valleys through low-cost heat storage to ensure stable power generation, and has the potential to serve as a basic power load or peak-shaving unit.

[0003] Generally, solar thermal power generation mainly includes four types: trough, linear Fresnel, dish and tower. Among them, the tower type solar thermal power generation system has a large capacity, high concentration ratio and operating temperature, and high efficiency. It is one of the fastest growing technologies. The system is mainly composed of several parts, such as the concentrating system, the heat absorption system, the heat storage system, the secondary circuit heat exchange system and the power generation system. Among them, the absorber in the heat absorption system is the key equipment for photothermal conversion, which usually includes a heat absorption tube, in which a molten salt working medium is arranged. The molten salt working medium is used to transfer the solar energy absorbed by the heat absorption tube.

[0004] At present, the absorbers of commercial solar tower thermal power stations are mostly external tube absorbers, which have large focusing edge angles, high power, simple structure and are easy to scale up. However, since this type of absorber tube bundle is directly exposed to the high-altitude environment, the reflection, radiation and convection losses are large, and the operating mode is sensitive to weather changes.

[0005] Frequent fluctuations in solar radiation intensity can easily cause uneven distribution of concentrated energy flow on the absorber tube bundle. For example, when clouds block the sun, the solar radiation energy received by the absorber decreases sharply, but the external heat dissipation of the absorber continues to exist. Therefore, the wall temperature of the absorber tube will drop sharply, which may cause condensation of molten salt in the absorber in severe cases. When the cloud cover disappears, solar radiation suddenly increases, which may cause local overheating of the tube bundle. The concentrated heat will cause thermal fatigue damage to the material, which will have a serious impact on the stable operation and life of the absorber. When strong winds occur, the external heat flow loss of the absorber tube increases, causing the tube wall temperature to drop. At the same time, strong winds may cause physical damage to the exposed absorber tube. Therefore, drastic weather changes will lead to reduced efficiency and shortened life of the absorber, and even damage, causing safety accidents. Summary of the invention

[0006] The present invention provides a heat absorber, comprising:

[0007] A heat absorbing tube, wherein a molten salt working medium is arranged in the heat absorbing tube, and the molten salt working medium is used to transfer the solar energy absorbed by the heat absorbing tube;

[0008] The heat absorber further comprises a protection mechanism, which is arranged outside the heat absorbing tube, and a thermochemical energy storage material is arranged inside the protection mechanism, and the protection mechanism is arranged in contact with the heat absorbing tube;

[0009] When the temperature of the heat absorbing tube is greater than the first preset temperature, the thermochemical energy storage material in the protection mechanism undergoes a reduction reaction to absorb heat, thereby lowering the temperature of the heat absorbing tube;

[0010] When the temperature of the heat absorbing tube is lower than the second preset temperature, the thermochemical energy storage material in the protection mechanism undergoes an oxidation reaction to release heat, causing the temperature of the heat absorbing tube to rise.

[0011] The present invention uses a protective mechanism to absorb and store heat from heat-concentrated areas when the temperature is too high, and releases the heat collected and stored at high temperatures when the temperature is too low. Among them, the main heat regulation method is: the thermochemical energy storage material set in the protective mechanism regulates the temperature through redox reactions. This not only ensures the stability of solar power generation, but also avoids local overheating of the absorber or solidification of the molten salt working fluid, thereby extending the service life of the absorber.

[0012] In the present invention, the protective mechanism is arranged on the outside of the heat absorber, which can play a certain role in heat preservation in strong wind weather, reduce the heat flow loss of the heat absorption tube to the outside, and at the same time avoid physical damage to the heat absorber caused by extreme weather.

[0013] The present invention also provides an operating method of the above heat absorber, comprising the following steps:

[0014] When sunlight shines on the outer surface of the protective mechanism, the thermochemical energy storage material inside the protective mechanism absorbs heat;

[0015] The protection mechanism transfers heat to the heat absorbing tube through heat conduction and strengthens the heat exchange by strengthening the heat exchange element;

[0016] The heat absorbing tube absorbs heat, and the molten salt working fluid in the heat absorbing tube heats up and stores heat;

[0017] When the temperature of the heat absorbing tube is greater than the first preset temperature, the thermochemical energy storage material in the protection mechanism undergoes a reduction reaction to absorb heat, thereby lowering the temperature of the heat absorbing tube;

[0018] When the temperature of the heat absorbing tube is lower than the second preset temperature, the thermochemical energy storage material in the protection mechanism undergoes an oxidation reaction to release heat, thereby increasing the temperature of the heat absorbing tube.

[0019] Through the above method, the present invention enables the protective mechanism to spontaneously undergo redox reactions as the temperature of the heat absorbing tube wall changes, store or release heat, reduce the temperature difference and power generation difference during heat peak and heat valley, and is conducive to stabilizing power generation.

[0020] In the present invention, the advantages of thermochemical energy storage technology such as high energy density and good cycle stability are fully utilized to convert heat at high temperatures into chemical energy of the material itself, which is utilized at lower temperatures to improve the utilization efficiency of solar energy.

[0021] In the present invention, the protective mechanism is arranged on the outside of the heat absorber, which can play a certain role in heat preservation in strong wind weather, reduce the heat flow loss of the heat absorption tube to the outside, and at the same time avoid physical damage to the heat absorber caused by extreme weather.

[0022] To sum up, compared with the prior art, the heat absorber and its operating method provided by the present invention can alleviate problems such as drastic temperature fluctuations, local excessive temperature, and solidification of molten salt working fluid in the actual operation of the heat absorber, perform physical and chemical protection on the heat absorber, and extend the life of the heat absorber.

[0023] In addition, preferably, there are multiple heat absorption tubes, and the multiple heat absorption tubes are arranged in sequence around the inner surface of the protection mechanism.

[0024] The use of multiple heat-absorbing tubes can collect solar radiation focused in all directions, improve the efficiency of solar energy absorption, and reduce the impact of changes in the sun's position on the collected heat.

[0025] In addition, arranging the heat absorbing pipes in sequence around the inner surface of the protective mechanism can enable the heat absorbing pipes and the protective mechanism to exchange heat in time. In this way, when the temperature is too high, the heat absorbing pipes can quickly transfer excess heat energy to the protective mechanism, and when the temperature of the heat absorbing pipes is low, the heat absorbing pipes can quickly obtain heat from the protective mechanism. In extreme weather, the outer protective mechanism can provide physical protection for the heat absorber and reduce heat dissipation losses.

[0026] In addition, preferably, the protection mechanism is formed into a porous structure.

[0027] The use of porous materials to form the protective structure can allow sunlight to pass through the pores, while at the same time maximizing the contact area between the protective structure and the air, improving heat exchange efficiency and promoting the occurrence of thermochemical reactions.

[0028] A micro heat pipe is arranged inside the hole of the protection mechanism.

[0029] The outer protective mechanism absorbs solar energy and converts it into thermal energy, heating the evaporation section of the micro heat pipe. The liquid working fluid evaporates after being heated, flows to the condensation section of the micro heat pipe under a small pressure difference, releases heat and condenses into liquid, and then flows back to the evaporation section by capillary action. This cycle is repeated, and the heat absorbed by the outer protective mechanism is quickly transferred to the inner protective material and the heat absorption pipe.

[0030] When solar radiation weakens and the temperature of the heat absorption tube drops, the thermochemical energy storage material undergoes an oxidation reaction to release heat. The micro heat pipe can quickly transfer the heat released by the energy storage material to the heat absorption tube, effectively preventing the molten salt from solidifying.

[0031] Therefore, arranging the micro heat pipes inside the pores of the protective material can enhance heat exchange, ensure the safe and stable operation of the heat absorber, and has the advantage of a compact structure.

[0032] Furthermore, the aperture of the protection mechanism increases from a surface close to the heat absorbing tube to a surface far from the heat absorbing tube.

[0033] The aperture of the protective mechanism far away from the heat absorbing tube is relatively large to ensure that sunlight can enter. The aperture of the protective mechanism close to the heat absorbing tube is relatively small and has a large porosity, which increases the heat exchange area and makes the heat transfer process between the protective mechanism and the heat absorbing tube faster and more efficient. The energy flux density of solar concentration is uneven. Where the concentration energy flux density is large, the aperture of the protective mechanism is relatively small to reduce the incident solar radiation; where the concentration energy flux density is small, the aperture is relatively large to increase the incident solar radiation. Therefore, the uneven distribution of the aperture of the protective mechanism can not only improve the heat exchange efficiency, but also adjust the concentration energy flux density to prevent local overheating of the tube bundle.

[0034] In addition, the number of holes on the surface of the protection mechanism close to the heat absorbing tube is greater than the number of holes on the surface of the protection mechanism far from the heat absorbing tube.

[0035] The holes on the surface of the protective mechanism away from the heat absorbing tube are large and sparse, so that the heat is effectively transferred in the heat absorbing tube. The holes on the surface of the protective mechanism close to the heat absorbing tube are small and dense, and the heat near the surface of the heat absorbing tube is evenly distributed, so that the heat absorbing tube is heated more evenly, the heat exchange efficiency is improved, and the safety of operation is ensured.

[0036] In addition, preferably, the heat absorber further comprises a temperature sensor for measuring the temperature of the heat absorption tube.

[0037] The temperature sensor can measure the temperature of the heat absorption tube in real time for safety monitoring.

[0038] In addition, as a preference, a microchannel structure is provided inside the protection mechanism;

[0039] The protection mechanism is in direct contact with the heat absorbing pipe or is connected via an enhanced heat transfer element.

[0040] In the present invention, a microchannel structure and an enhanced heat transfer element are added inside the protection mechanism to enhance heat transfer. When solar radiation increases, excessive or overly concentrated heat is converted and stored, effectively preventing the heat absorption pipe wall temperature from being too high; when solar radiation decreases, the energy released by the protection mechanism is promptly transferred to the heat absorption pipe, effectively preventing the heat absorption pipe wall temperature from being too low. In this way, the temperature of the heat absorber is stabilized within a safe operating range, thereby increasing the operating life of the heat absorber.

[0041] In addition, preferably, the thermochemical energy storage material inside the protective mechanism is made of metal oxide or perovskite.

[0042] When the temperature of the heat absorbing tube is greater than the first preset temperature, the metal oxide or perovskite spontaneously undergoes a reduction reaction, absorbs heat, and reduces the temperature of the heat absorbing tube; when the temperature of the heat absorbing tube is less than the second preset temperature, the metal oxide or perovskite spontaneously undergoes an oxidation reaction, releases heat, and increases the temperature of the heat absorbing tube. This oxidation-reduction reaction directly uses air as the gas reaction medium, which is low-cost, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a three-dimensional schematic diagram of a heat absorber when the protective mechanism is a porous structure in the first embodiment of the present invention;

[0044] Figure 2 is a three-dimensional schematic diagram of a heat absorber when the aperture distribution of the protection mechanism is uneven in the second embodiment of the present invention;

[0045] Figure 3 is a top view of a heat absorber when a temperature sensor is provided in Embodiment 3 of the present invention;

[0046] Figure 4 is a top view of the fourth embodiment of the present invention when a microchannel structure and an enhanced heat transfer element are provided;

[0047] Figure 5 is a three-dimensional schematic diagram of a microchannel structure in a fourth embodiment of the present invention;

[0048] Figure 6 It is a cross-sectional schematic diagram of a micro heat pipe provided in a channel in a fifth embodiment of the present invention.

[0049] Description of reference numerals:

[0050] 1-heat absorbing tube; 2-protective mechanism; 3-porous structure; 4-temperature sensor; 5-fin; 6-microchannel structure; 7-liquid; 8-micro heat pipe; 9-vapor; 10-pore. DETAILED DESCRIPTION

[0051] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification. The accompanying drawings schematically and simply show the structure of the heat absorber.

[0052] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0053] Implementation Method 1

[0054] The present invention provides a heat absorber, referring to Figure 1 As shown, including:

[0055] The heat absorbing tube 1 has a molten salt working medium disposed therein, and the molten salt working medium is used to transfer the solar energy absorbed by the heat absorbing tube 1 .

[0056] The protection mechanism 2 is arranged outside the heat absorbing tube 1 , and a thermochemical energy storage material is arranged inside the protection mechanism 2 . The protection mechanism 2 is arranged in contact with the heat absorbing tube 1 .

[0057] When the temperature of the heat absorbing tube 1 is greater than the first preset temperature, the protection mechanism 2 absorbs heat, causing the thermochemical energy storage material to undergo a reduction reaction and store heat, thereby reducing the temperature of the heat absorbing tube 1;

[0058] When the temperature of the heat absorbing tube 1 is lower than the second preset temperature, the thermochemical energy storage material undergoes an oxidation reaction to release heat and transfers the heat to the heat absorbing tube 1 .

[0059] The present invention adjusts the temperature difference caused by the change of solar radiation with weather and time by setting the protection mechanism 2, thereby stabilizing the power generation and extending the service life of the heat absorber.

[0060] The protection mechanism 2 is arranged close to the heat absorbing tube 1 so as to facilitate faster heat exchange. When the temperature of the heat absorbing tube 1 is high, the thermochemical energy storage material in the protection mechanism 2 absorbs heat, causing the surface temperature of the heat absorbing tube 1 to drop. When the temperature of the heat absorbing tube 1 is low, the protection mechanism 2 releases the stored heat and transfers it to the heat absorbing tube 1 to prevent the molten salt working medium inside the heat absorbing tube 1 from solidifying and clogging.

[0061] At this time, the protective mechanism 2 is arranged on the outside of the heat absorber. In strong wind weather, the heat loss of the heat absorption tube 1 to the outside increases, resulting in a decrease in the temperature of the tube wall. The outer protective mechanism 2 can play a certain role in heat preservation. Extreme weather may cause physical damage to the exposed heat absorption tube 1. The protective mechanism 2 arranged on the outside can protect the heat absorption tube 1 and extend its service life. In addition, the protective mechanism 2 is arranged on the outside, which can better contact the air and provide favorable conditions for the oxidation reaction. There is no need to set up air supply equipment such as a fan separately, which reduces costs.

[0062] Among them, the first preset temperature can be set as the maximum safe operating temperature of the heat absorber tube 1 to avoid the temperature of the heat absorber tube 1 being too high after it exceeds its maximum safe operating temperature and causing thermal fatigue damage. The second preset temperature can be set as the minimum safe operating temperature of the heat absorber tube 1 to avoid the condensation of the molten salt working fluid in the heat absorber tube 1 and causing fatal damage to the heat absorber. Of course, the first preset temperature can also be set to be 1-3°C lower than the maximum operating temperature of the heat absorber tube 1, and the second preset temperature can be set to be 1-3°C higher than the minimum operating temperature of the heat absorber tube 1. At this time, controlling the temperature of the heat absorber tube 1 within a smaller temperature difference range can effectively avoid the shortening of the heat absorber life caused by the drastic heating and cooling of the heat absorber tube 1, protect the heat absorber tube 1, and avoid safety accidents.

[0063] In particular, there are multiple heat absorbing tubes 1, which can not only increase the power generation, but also improve the efficiency of heat exchange. Through multiple heat absorbing tubes 1, solar radiation is collected from different directions, and the heat is also distributed more evenly in the heat absorber. Multiple heat absorbing tubes 1 are arranged in sequence around the inner surface of the protective mechanism 2. When the heat of the heat absorbing tube 1 is concentrated or insufficient, the heat can be transferred to the heat absorbing tube 1 more quickly, thereby achieving the effect of protecting the heat absorber and stabilizing power generation.

[0064] The thermochemical energy storage materials used are mainly metal oxides or perovskites, etc., which achieve the purpose of controlling the wall temperature of the heat absorption tube 1 by performing redox reactions under different conditions.

[0065] The specific control methods are as follows:

[0066] When the solar radiation is too strong and causes the tube wall temperature to be too high or locally overheated, the heat is transferred from the heat absorbing tube 1 to the protective mechanism 2. The thermochemical energy storage material in the protective mechanism 2 undergoes a reduction reaction under the condition of rising temperature, converting the thermal energy into chemical energy, which is stored in the low-valent thermochemical energy storage material.

[0067] When clouds block solar radiation or extreme weather occurs, solar radiation weakens and the temperature of the heat absorbing tube 1 decreases. At this time, the oxygen in the air reacts with the low-valent thermochemical energy storage material to release heat. The heat released by the protective mechanism 2 can not only keep the molten salt working medium in the heat absorbing tube 1 warm, but also be converted into electrical energy to improve the quality of power generation.

[0068] The metal oxide may include any one of the following metal oxides, or any combination of multiple metal oxides:

[0069] Copper oxide, cobalt oxide, manganese oxide, barium oxide, iron oxide, etc.

[0070] The chemical reaction equation can be:

[0071]

[0072]

[0073]

[0074]

[0075]

[0076] Compared with ordinary metal oxides, perovskite-type metal oxides can allow active metal elements to exist in mixed valence states, have non-stoichiometric oxygen ratios, and have diverse and controllable reactions.

[0077] Specifically, perovskite can react in a continuous temperature range. As a thermochemical energy storage material, perovskite is conducive to improving the ability of the protection mechanism 2 to adjust the temperature, thereby improving the ability of the protection mechanism 2 to protect the heat absorption tube 1. In particular, doping ions in perovskite can also change the reaction temperature range of the perovskite, thereby adapting to adjusting the temperature of the heat absorption tube 1 with different temperature difference requirements.

[0078] Taking perovskite as ABO3 as an example, its chemical reaction equation is as follows:

[0079]

[0080] It is clear to those skilled in the art that thermochemical energy storage utilizes reversible chemical reactions to achieve energy storage and release through the breaking and recombination of chemical bonds, which can achieve efficient conversion and long-term storage of energy.

[0081] In the present embodiment, the protection mechanism 2 is formed as a porous structure 3 .

[0082] Thermochemical energy storage material powder can be mixed with a binder and directly pressed to form a porous structure 3, or the thermochemical energy storage material can be directly coated on the porous structure 3, such as foam ceramics, honeycomb ceramics, etc.

[0083] The porous structure 3 allows sunlight to pass through the pores and can increase the reaction area of ​​oxygen and thermochemical energy storage materials, which is conducive to the rapid redox reaction, thereby storing or releasing heat in a timely manner, controlling the temperature of the heat absorption tube 1 within a safe operating range, thereby reducing the possibility of molten salt condensation and improving the operating stability and efficiency of the heat absorber. In addition, the porous structure 3 is also conducive to gas circulation, increasing the heat exchange area, accelerating the reaction rate, and improving the heat exchange efficiency.

[0084] Preferably, the protection mechanism 2 is formed into a cylindrical, flat or curved plate shape. The protection mechanism 2 in the cylindrical, flat or curved plate shape can contact the heat absorbing tube 1 as much as possible, increase the heat exchange area between the protection mechanism 2 and the heat absorbing tube 1, and improve the efficiency of heat exchange.

[0085] Based on the above considerations, the present invention adjusts the energy by providing a protection mechanism 2 with heat storage and heat release functions, thereby improving the safety of the heat absorber and the stability of solar power generation.

[0086] Implementation Method 2

[0087] The second embodiment of the present invention provides a heat absorber. The second embodiment is a further improvement of the first embodiment. The main improvement is that in the second embodiment of the present invention, see Figure 2 As shown, the aperture of the protection mechanism 2 increases from a surface close to the heat absorbing tube 1 to a surface far from the heat absorbing tube 1 , ie, the light-facing surface.

[0088] In particular, where the density of the focused energy flux of the protective mechanism 2 is large, the aperture is relatively small; and where the density of the focused energy flux is small, the aperture is relatively large.

[0089] In this embodiment, the aperture distribution of the protection mechanism 2 is uneven, which can not only improve the heat exchange efficiency, but also adjust the density of the concentrated energy flux to prevent local overheating of the tube bundle.

[0090] The aperture of the protection mechanism 2 far away from the heat absorbing tube 1 is relatively large, ensuring that more sunlight can enter and improving the absorption rate of solar radiation; the aperture of the protection mechanism 2 close to the heat absorbing tube 1 is relatively small, and the porosity is large, which increases the heat exchange area, making the heat transfer process between the protection mechanism 2 and the heat absorbing tube 1 more rapid and efficient. The energy flux density of solar concentration is uneven. Where the concentration energy flux density is large, the aperture of the protection mechanism 2 is relatively small, reducing the incident solar radiation; where the concentration energy flux density is small, the aperture is relatively large, increasing the incident solar radiation, achieving the purpose of adjusting the energy flux density.

[0091] Combination Figure 2 From the perspective of the embodiment, under normal circumstances, the concentrated light flux density in the middle of the heat absorbing tube 1 is larger, while that at the two ends is smaller. Therefore, the aperture of the protection mechanism 2 corresponding to the middle of the heat absorbing tube 1 is smaller, while the aperture of the protection mechanism 2 at the two ends is larger.

[0092] Therefore, the uneven distribution of the apertures of the protection mechanism 2 can increase the incident solar radiation and improve the heat exchange efficiency, while making the heat absorbing tube 1 heated more evenly and ensuring the safety of operation.

[0093] In particular, the number of holes on the surface of the protective mechanism 2 close to the heat absorbing tube 1 is greater than the number of holes on the surface of the protective mechanism 2 far from the heat absorbing tube 1, that is, the holes on the surface of the protective mechanism 2 close to the heat absorbing tube 1 are small and dense, and the holes on the surface of the protective mechanism 2 far from the heat absorbing tube 1 are large and sparse, so that heat can be effectively transferred in the heat absorbing tube 1, and the heat close to the surface of the heat absorbing tube 1 is evenly distributed, so that the heat absorbing tube 1 is heated more evenly, the heat exchange efficiency is improved, and the safety of operation is guaranteed.

[0094] Implementation Method 3

[0095] The third embodiment of the present invention provides a heat absorber. The third embodiment is a further improvement of the second embodiment. The main improvement is that in the third embodiment of the present invention, referring to Figure 3 As shown, the heat absorber includes a temperature sensor 4 for measuring the wall temperature of the heat absorbing tube 1. The temperature sensor 4 can measure the wall temperature of the heat absorbing tube 1 in real time, and monitor and provide feedback on the operating state of the protection mechanism 2.

[0096] The specific feedback mechanism can be as follows:

[0097] The temperature sensor 4 measures the wall temperature of the heat absorbing tube 1 and compares the measured temperature with a preset temperature;

[0098] When the measured temperature is within the range of the first preset temperature and the second preset temperature, it indicates that the heat absorber and the protection mechanism 2 operate normally;

[0099] When the measured temperature is higher than the first preset temperature or lower than the second preset temperature, it indicates that the protection mechanism 2 does not work normally, and the temperature sensor 4 sends a signal to the control system to manually eliminate the fault.

[0100] An alarm may be provided in the control system. When the protection mechanism 2 does not work normally and the temperature sensor 4 feeds back information to the control system, the control system controls the alarm to sound an alarm and notify the staff.

[0101] Implementation Method 4

[0102] The fourth embodiment of the present invention provides a heat absorber. This embodiment is a further improvement of any one of the first to third embodiments. The main improvement is that in the fourth embodiment of the present invention, referring to Figure 4 As shown, a microchannel structure 6 is provided inside the protection mechanism 2. The protection mechanism 2 is in direct contact with the heat absorbing tube 1 or is connected via an enhanced heat transfer element, such as a fin 5.

[0103] The microchannel structure 6 is arranged inside the protection mechanism 2, referring to Figure 5 As shown, the transverse and longitudinal microchannels are arranged in an interlaced manner, which effectively increases the heat exchange area. When the sunlight is absorbed by the outer protective mechanism 2, the heat can be quickly transferred to the inner protective mechanism 2 and the heat absorption tube 1. When the solar radiation is enhanced or the local concentrated energy flux density is too large, the thermochemical energy storage material undergoes a reduction reaction, which can enhance the heat exchange through the internal microchannels, increase the reaction rate, convert the excess heat into chemical energy and store it, and effectively prevent the heat absorption tube 1 from overheating.

[0104] Among them, a metal mesh is arranged inside the protective structure, and the metal mesh can enhance the heat exchange of the thermochemical energy storage material. When the solar radiation is enhanced or the local focused energy flux density is too large, the thermochemical energy storage material undergoes a reduction reaction, and the heat exchange is enhanced through the internal metal mesh, thereby increasing the reaction rate, converting excessive or over-concentrated heat into chemical energy for storage, and effectively preventing the wall of the heat absorption tube 1 from overheating.

[0105] When clouds block solar radiation or the intensity of solar radiation weakens, the thermochemical energy storage material undergoes an oxidation reaction, and the heat exchange is enhanced through the microchannels inside the material. The released heat is used to heat the heat absorption tube 1, thereby reducing the possibility of solidification of the molten salt working fluid, and ultimately improving the operating stability and efficiency of the heat absorber.

[0106] Implementation Method 5

[0107] The fifth embodiment of the present invention provides a heat absorber, which is different from any one of the first to fourth embodiments. The main difference is that in the fifth embodiment of the present invention, referring to Figure 6 As shown, a micro heat pipe 8 is provided inside the hole 10 of the protection mechanism 2 .

[0108] The outer protective mechanism 2 absorbs solar energy and converts it into thermal energy, heating the evaporation section of the micro heat pipe 8. The liquid 7 working fluid evaporates after being heated, flows to the condensation section of the micro heat pipe 8 under a small pressure difference, releases heat and condenses into liquid 7, and then flows back to the evaporation section by capillary action. This cycle is repeated to quickly transfer the heat absorbed by the outer protective mechanism 2 to the inner protective material and the heat absorbing tube 1.

[0109] When solar radiation weakens and the temperature of the heat absorbing tube 1 drops, the thermochemical energy storage material undergoes an oxidation reaction to release heat, and the micro heat pipe 8 can quickly transfer the heat released by the energy storage material to the heat absorbing tube 1, effectively preventing the molten salt from solidifying.

[0110] Therefore, arranging the micro heat pipe 8 inside the pore 10 of the protective material can enhance heat exchange, ensure the safe and stable operation of the heat absorber, and has the advantage of a compact structure.

[0111] Implementation Method 6

[0112] A sixth embodiment of the present invention provides an operating method of a heat absorber, which is a method for controlling the heat absorber of any one of the first to fifth embodiments, comprising the following steps:

[0113] Sunlight shines on the outer surface of the protective mechanism 2, and the protective material absorbs heat;

[0114] The protection mechanism 2 transfers heat to the heat absorbing tube 1 through the porous structure 3, and enhances the heat exchange through the enhanced heat exchange element;

[0115] The heat absorbing tube 1 absorbs heat and heats the molten salt working medium;

[0116] When the temperature of the heat absorbing tube 1 is greater than the first preset temperature, the thermochemical energy storage material in the protection mechanism 2 undergoes a reduction reaction to absorb heat, thereby lowering the temperature of the heat absorbing tube 1;

[0117] When the temperature of the heat absorbing tube 1 is lower than the second preset temperature, the thermochemical energy storage material in the protection mechanism 2 undergoes an oxidation reaction to release heat, causing the temperature of the heat absorbing tube 1 to rise.

[0118] The specific adjustment method is: when the temperature is too high, the heat in the heat-concentrated area is absorbed and stored; when the temperature is too low, the heat collected and stored at high temperature is released.

[0119] The key to energy regulation is that the thermochemical energy storage material in the protection mechanism 2 spontaneously undergoes redox reaction according to temperature changes to achieve the conversion of thermal energy and chemical energy. The heat exchange is enhanced by the microchannel structure 6 and the micro heat pipe 8 to quickly achieve heat exchange between the protection mechanism 2 and the heat absorbing pipe 1.

[0120] The temperature of the heat absorber is adjusted by the protection mechanism 2, which not only ensures the stability of solar power generation, but also prolongs the service life of the heat absorber.

[0121] Those skilled in the art will appreciate that, in the above-mentioned embodiments, many technical details are provided in order to enable readers to better understand the present application. However, even without these technical details and various changes and modifications based on the above-mentioned embodiments, the technical solutions claimed for protection in the claims of the present application can be basically realized. Therefore, in practical applications, various changes can be made to the above-mentioned embodiments in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A heat absorber, comprising: A heat absorbing tube, wherein a molten salt working medium is arranged in the heat absorbing tube, and the molten salt working medium is used to transfer the solar energy absorbed by the heat absorbing tube; The heat absorber is characterized in that the heat absorber further comprises a protection mechanism, the protection mechanism is arranged on the outside of the heat absorbing tube, a thermochemical energy storage material is arranged inside the protection mechanism, the protection mechanism is arranged in contact with the heat absorbing tube, the protection mechanism is formed into a porous structure, and the pore size of the protection mechanism changes from small to large from the surface close to the heat absorbing tube to the surface away from the heat absorbing tube; When the temperature of the heat absorbing tube is greater than the first preset temperature, the protection mechanism absorbs heat, causing the thermochemical energy storage material to undergo a reduction reaction to store heat and reduce the temperature of the heat absorbing tube; When the temperature of the heat absorbing tube is lower than the second preset temperature, the thermochemical energy storage material undergoes an oxidation reaction to release heat and transfers the heat to the heat absorbing tube.

2. The heat absorber according to claim 1, characterized in that: There are a plurality of heat absorbing tubes, and the plurality of heat absorbing tubes are arranged in sequence around the inner surface of the protection mechanism.

3. The heat absorber according to claim 1, characterized in that: The number of holes on the surface of the protection mechanism close to the heat absorbing tube is greater than the number of holes on the surface of the protection mechanism far from the heat absorbing tube.

4. The heat absorber according to claim 1, characterized in that: The heat absorber further includes a temperature sensor for measuring the temperature of the heat absorption tube.

5. The heat absorber according to claim 1, characterized in that: A microchannel structure is provided inside the protection mechanism; The protection mechanism and the heat absorbing tube are connected via a heat transfer enhancement element arranged between the protection mechanism and the heat absorbing tube.

6. The heat absorber according to claim 5, characterized in that: A micro heat pipe is arranged inside the hole of the protection mechanism.

7. The heat absorber according to any one of claims 1 to 6, characterized in that: The thermochemical energy storage material inside the protection mechanism is metal oxide or perovskite.

8. A method for operating a heat absorber according to any one of claims 1 to 7, characterized in that: The steps include: When sunlight shines on the outer surface of the protective mechanism, the thermochemical energy storage material inside the protective mechanism absorbs heat; The protection mechanism transfers heat to the heat absorbing tube through heat conduction and strengthens the heat exchange by strengthening the heat exchange element; The heat absorbing tube absorbs heat, and the molten salt working fluid in the heat absorbing tube heats up and stores heat; When the temperature of the heat absorbing tube is greater than the first preset temperature, the thermochemical energy storage material in the protection mechanism undergoes a reduction reaction to absorb heat, thereby lowering the temperature of the heat absorbing tube; When the temperature of the heat absorbing tube is lower than the second preset temperature, the thermochemical energy storage material in the protection mechanism undergoes an oxidation reaction to release heat, thereby increasing the temperature of the heat absorbing tube.

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