CN218672666U

CN218672666U - Linear solar heat collection salt dredging system

Info

Publication number: CN218672666U
Application number: CN202223082015.6U
Authority: CN
Inventors: 范多旺; 范多进; 孔令刚; 范玉磊; 李文; 张志勇; 张重重; 李博; 赵锡源; 赵富军
Original assignee: Dunhuang Dacheng Juneng New Energy Equipment Co ltd; Dunhuang Dacheng Shengneng New Energy Technology Co ltd; Lanzhou Dacheng Concetrate Solar Technology Co ltd; LANZHOU DACHENG VACUUM TECHNOLOGY CO LTD; LANZHOU DACHENG TECHNOLOGY CO LTD
Current assignee: Dunhuang Dacheng Juneng New Energy Equipment Co ltd; Dunhuang Dacheng Shengneng New Energy Technology Co ltd; Lanzhou Dacheng Concetrate Solar Technology Co ltd; LANZHOU DACHENG VACUUM TECHNOLOGY CO LTD; LANZHOU DACHENG TECHNOLOGY CO LTD
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-03-21
Anticipated expiration: 2032-11-21

Abstract

The utility model discloses a linear solar heat collection salt dispersing system, belonging to the technical field of solar heat systems, comprising a heat collection field, and a cold salt tank, a hot salt tank and a compressed air source which are respectively communicated with the heat collection field; the cold salt tank is communicated with a heat collection inlet of the heat collection field, and the hot salt tank and the compressed air source are both communicated with a heat collection outlet of the heat collection field; and the compressed air source is used for supplementing high-pressure air into the heat collection field when the salt is dispersed, and increasing the power of the molten salt flowing back to the cold salt tank from the heat collection field. The utility model discloses an utilize compressed air source to supply high-pressure gas to the thermal-arrest field, can increase the power of fused salt backward flow, improve and dredge salt efficiency, reduce and dredge salt time, simultaneously, reduce the reliance to modes such as electric tracing, reduce and dredge the setting of salt jar and dredging the salt pipeline, the construction and the running cost of lowering system.

Description

Linear solar heat collection salt dredging system

Technical Field

The utility model relates to a solar thermal system technical field especially relates to a linear solar energy collection salt dredging system.

Background

Solar energy is the largest renewable energy source which can be developed on the earth at present and is applied in a large area, the heat collection forms of the solar energy are divided into two major categories, namely linear and nonlinear, the linear heat collection is most widely applied at present in a groove type and a linear Fresnel type, and most of heating media are water, heat conduction oil and molten salt. As the temperature of the solar heat collecting medium increases, the power generation efficiency increases, and molten salt is becoming widely used as the solar heat collecting medium. The fused salt is used as a heat-conducting medium, and has the advantages of high power generation efficiency and difficult blockage due to poor temperature control, so that the pipeline needs to be subjected to electric tracing to prevent the fused salt from being solidified, the time needs to be shortened in the processes of injecting and dispersing the salt, and the possibility of faults is reduced.

At present, linear solar energy fused salt heat collecting systems are all equipped with salt dredging systems, and the salt dredging systems are only started when being used as salt dredging, and are equipped with special salt dredging pipelines, salt dredging tanks and salt dredging pump systems, and also have electric heat tracing and valve devices of the salt dredging pipelines, so that the running cost of the whole system is greatly increased, the salt dredging time of the system is increased, and the risk of possible problems is increased.

The Chinese patent with the granted publication number of CN206522933U discloses a salt dredging system for a solar thermal power plant, which comprises a cold salt tank, a hot salt tank, a salt dredging tank and a molten salt furnace; the top of the salt dredging tank is provided with a molten salt inlet and a salt dredging pump, and the salt dredging tank is also provided with a heating device; the liquid outlet end of the salt dredging pump is respectively communicated with a molten salt inlet of the molten salt furnace, a molten salt inlet of the cold salt tank and a molten salt inlet of the hot salt tank, and a molten salt overflow outlet on the molten salt furnace is respectively communicated with a molten salt inlet of the salt dredging tank and a molten salt inlet of the hot salt tank; the salt dredging tank is located at the lowest position of the system, and a molten salt inlet of the salt dredging tank is respectively communicated with a molten salt outlet at the lower part of the cold salt tank and a molten salt outlet at the lower part of the hot salt tank. This scheme is provided with in addition and dredges the salt jar and is used for dredging the salt, later with the fused salt of dredging in the salt jar transshipment to cold salt jar again, leads to the efficiency of dredging the salt lower.

The Chinese patent with the granted publication number of CN210179929U discloses a solar thermal power station salt dredging system arrangement structure, which comprises a salt dredging tank, a salt discharging groove, a salt dredging pump and a salt dredging pit, wherein the salt dredging tank is arranged at the bottom of the salt dredging pit, the salt dredging pump is arranged above the salt dredging tank, the salt discharging groove is arranged in the salt dredging pit, and the top surface of the salt discharging groove is lower than the bottom surface of the salt dredging tank; the salt dredging tank is communicated with the salt discharging groove through a pipeline, and a valve is arranged on the pipeline; the salt inlet of the salt dredging pump is communicated with the salt dredging tank, the salt dredging tank is provided with an exhaust port, and the exhaust port is connected with a pipeline for exhausting. According to the scheme, the salt dredging pump is used as power for the salt dredging process, if the temperature of the molten salt is low, the molten salt is not easy to be conveyed by the salt dredging pump, and modes such as electric tracing and the like need to be additionally adopted, so that the salt dredging efficiency is reduced, and the salt dredging cost is increased.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a linear solar energy collection salt dredging system to solve the problem that above-mentioned prior art exists, supplement high-pressure gas to the thermal-arrest field through utilizing compressed air source, can increase the power of fused salt backward flow, improve salt dredging efficiency, reduce salt dredging time, simultaneously, reduce the reliance to modes such as electric tracing, reduce salt dredging tank and salt dredging pipe way's setting, reduce system's construction and running cost.

In order to achieve the above object, the utility model provides a following scheme:

the utility model provides a linear solar heat collection salt dispersing system, which comprises a heat collection field, a cold salt tank, a hot salt tank and a compressed air source, wherein the cold salt tank, the hot salt tank and the compressed air source are respectively communicated with the heat collection field; the cold salt tank is communicated with a heat collection inlet of the heat collection field, and the hot salt tank and the compressed air source are both communicated with a heat collection outlet of the heat collection field; and the compressed air source is used for supplementing high-pressure air into the heat collection field when the salt is dispersed, and increasing the power of the molten salt flowing back to the cold salt tank from the heat collection field.

Preferably, the heat collecting field is disposed obliquely, and the height of the heat collecting inlet is lower than that of the heat collecting outlet.

Preferably, the cold salt tank and the hot salt tank are both positioned below the ground level, and the distance between the top of the tank and the ground level is 1-3 m.

Preferably, the heat collection outlet is communicated with the hot salt tank through a hot salt pipeline, and a third valve is arranged on the hot salt pipeline.

Preferably, the hot salt pipeline is provided with a branch communicated with the compressed air source, and a first valve is arranged on the branch.

Preferably, the heat collection inlet is communicated with the cold salt tank through a cold salt pipeline, a second valve is arranged on the cold salt pipeline, and a cold salt pump is arranged between the second valve and the heat collection inlet.

Preferably, the heat collection field adopts a linear fresnel type light-gathering and heat-collecting system, the linear fresnel type light-gathering and heat-collecting system comprises a primary reflecting mirror surface and a secondary reflecting mirror surface, incident light is reflected to the secondary reflecting mirror surface through the primary reflecting mirror surface, the secondary reflecting mirror surface irradiates the reflected light to the heat collection tube of the heat collection field, and the area of the primary reflecting mirror surface is larger than that of the secondary reflecting mirror surface.

The utility model also provides a salt dredging method, including following step:

s1: stopping the circulation of the heat collection molten salt, and enabling the molten salt to flow back to the cold salt tank from the heat collection field;

s2: when the flow speed of the molten salt is slowed or stopped, a compressed air source is started to supplement high-pressure air into the heat collection field, so that the internal pressure of the heat collection field is improved;

s3: closing a compressed air source, and continuously refluxing the molten salt under the action of the internal pressure of the heat collection field;

s4: and (4) slowing down or stopping the flow speed of the molten salt again, starting the compressed air source again, and repeating the step (S2) and the step (S3) until the molten salt in the heat collecting field is completely discharged.

Preferably, when the internal pressure of the heat collection field is reduced to below 0.8MPa, the compressed air source is started, the pressure is increased to be greater than 0.8MPa, then the compressed air source is closed, and when the pressure is reduced to below 0.8MPa again, the compressed air source is started again.

Preferably, after the temperature of the fused salt is reduced to 350 ℃, the circulation of the heat collection fused salt is stopped, and the fused salt starts to flow back to the cold salt tank from the heat collection field; and judging whether the molten salt is discharged completely by judging whether the compressed gas reaches the cold salt tank.

The utility model discloses for prior art gain following technological effect:

(1) The utility model can increase the power of molten salt backflow, improve the salt dredging efficiency, reduce the salt dredging time, reduce the dependence on electric tracing and other modes, reduce the arrangement of the salt dredging tank and the salt dredging pipeline, and reduce the construction and operation cost of the system by utilizing the compressed air source to supplement high-pressure air to the heat collection field;

(2) The utility model discloses the slope of thermal-arrest field sets up to make the height of thermal-arrest import be less than the height of thermal-arrest export, can utilize the fused salt dead weight to make it flow out by the thermal-arrest import in thermal-arrest field when dredging salt, simultaneously, all be located the horizon below with cold salt jar and hot salt jar, improve the difference in height of thermal-arrest field and cold salt jar, can utilize higher difference in height to increase the power that the fused salt flowed back to the cold salt jar automatically;

(3) The utility model discloses an open compressed air source repeatedly, supply with compressed gas in the thermal-arrest field repeatedly, can make the repetition reach certain pressure in the thermal-arrest field, provide effectual power for the flow of fused salt to, the pressure limit is set for 0.8MPa, can enough fully guarantee the flow of fused salt and can avoid the too big destruction that leads to the thermal-arrest field of pressure again.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic structural view of the linear Fresnel type light and heat collecting system of the present invention;

FIG. 3 is a schematic diagram of the structure of the primary reflector in FIG. 2;

FIG. 4 is a schematic diagram of the structure of the secondary reflector in FIG. 2;

wherein, 1, collecting heat field; 11. a primary mirror structure; 111. a primary mirror surface; 112. glue dispensing; 113. a support box; 12. a secondary mirror structure; 121. a secondary mirror surface; 122. a support frame; 13. a heat collecting pipe; 14. light rays; 15. a heat collection inlet; 16. a heat collection outlet; 2. a cold salt tank; 3. a hot salt tank; 4. compressing a gas source; 5. a first valve; 6. a second valve; 7. a third valve; 8. a cold salt pump.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

The utility model aims at providing a linear solar energy collection salt dredging system to solve the problem that prior art exists, supplement high-pressure gas to the thermal-arrest field through utilizing compressed air source, can increase the power of fused salt backward flow, improve salt dredging efficiency, reduce salt dredging time, simultaneously, reduce the reliance to modes such as electric tracing, reduce salt dredging tank and salt dredging pipe way's setting, the construction and the running cost of lowering system.

In order to make the above objects, features and advantages of the present invention more comprehensible, the present invention is described in detail with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, the utility model provides a linear solar heat collection salt dispersing system, which comprises a heat collection field 1, and a cold salt tank 2, a hot salt tank 3 and a compressed air source 4 which are respectively communicated with the heat collection field 1, wherein the heat collection field 1 can adopt a groove type or linear fresnel type structure; the cold salt tank 2 is used for containing molten salt with relatively low temperature, and the hot salt tank 3 is used for containing molten salt with relatively high temperature. The cold salt tank 2 is communicated with a heat collection inlet 15 of the heat collection field 1, and the hot salt tank 3 and the compressed air source 4 are both communicated with a heat collection outlet 16 of the heat collection field 1. During heat collection, the temperature of the molten salt in the cold salt tank 2 is raised to a certain temperature after the molten salt absorbs solar energy through the heat collection field 1, the molten salt enters the hot salt tank 3, and the molten salt in the hot salt tank 3 is subjected to corresponding heat conversion and utilization. In order to ensure the fluidity of the molten salt and the availability of heat energy, the temperature of the cold salt tank 2 is generally about 290 ℃, and the temperature of the hot salt tank 3 is generally about 550 ℃, which are relatively fixed. The compressed air source 4 may be compressed air or nitrogen, and may be supplied by a compressor or a compressed air tank. During salt dredging, the compressed air source 4 can supplement high-pressure air into the heat collection field 1, and the compressed air is utilized to improve the pressure in the heat collection field 1, so that the power of the fused salt flowing back from the heat collection field 1 to the cold salt tank 2 is increased. It should be noted that the inlet of the compressed air source 4 is communicated with the heat collecting outlet 16, so as to utilize the pressure of the compressed air to push the molten salt to flow from the heat collecting outlet 16 to the heat collecting inlet 15. In addition, because the flowing speed of the molten salt is limited in the salt dredging process, if the compressed gas is continuously supplied to the heat collection field 1, the pressure in the heat collection field 1 is continuously increased, and the heat collection field 1 is highly likely to be damaged along with the increase of the pressure, therefore, a mode of discontinuously supplying the compressed gas can be adopted, namely, when the compressed gas is supplied, the gas supply is stopped after the heat collection field 1 reaches a certain pressure, the existing pressure environment is utilized to push the molten salt to flow, after the molten salt flows for a period of time, the gas supply is continued after the pressure in the heat collection field 1 is reduced, and the gas supply is repeated in such a way until the salt dredging operation is completed. The utility model discloses an utilize compressed air source 4 to 1 supplementary high-pressure gas in thermal-arrest field, can increase the power of fused salt backward flow, improve and dredge salt efficiency, reduce and dredge salt time, simultaneously, reduce the reliance to modes such as electric tracing, reduce and dredge the setting of salt jar and dredging the salt pipeline, the construction and the running cost of lowering system.

The heat collection field 1 can be obliquely arranged, that is, each heat collection pipe 13 forming the heat collection field 1 is obliquely arranged, and the height of the heat collection inlet 15 is lower than that of the heat collection outlet 16, so that when salt is removed, the molten salt flows out from the heat collection inlet 15 of the heat collection field 1 by the self weight of the molten salt and flows back to the cold salt tank 2. In order to ensure better flow of the fused salt, the resistance of the fused salt to continue flowing due to vacuum or negative pressure in the heat collecting pipe 13 caused by the self-weight backflow of the fused salt is avoided. A vent valve port communicating with the atmosphere may be provided at the heat collection outlet 16 or indirectly, or compressed gas may be provided directly by the supplemental compressed gas source 4 to avoid the influence of vacuum or negative pressure.

Further, both the cold salt tank 2 and the hot salt tank 3 can be located below the ground level, generally, the distance between the tank tops of the cold salt tank 2 and the hot salt tank 3 and the ground level can be 1-3 m, preferably 2m, and the distance between the tank tops and the ground level can be changed according to the pressure difference of the project pipeline system. The cold salt tank 2 and the hot salt tank 3 are both positioned below the ground level, so that the height difference between the heat collection field 1 and the cold salt tank 2 can be improved, the power of the molten salt flowing back to the cold salt tank 2 automatically can be increased by utilizing the higher height difference, and the energy requirement during salt dredging is reduced.

The heat collection outlet 16 and the hot salt tank 3 can be communicated through a hot salt pipeline, and the hot salt pipeline is provided with a third valve 7. The third valve 7 can control the connection and disconnection between the hot salt tank 3 and the heat collecting field 1. In general, the third valve 7 is opened during a heat collecting cycle, and the third valve 7 is closed during salt rejection or shutdown.

The hot salt pipeline can also be provided with a branch communicated with a compressed air source 4, and a first valve 5 is arranged on the branch. During the heat collecting cycle, the first valve 5 is in a closed state, and at this time, the compressed gas of the compressed gas source 4 does not and does not need to enter the heat collecting field 1. In the salt shedding, the first valve 5 is opened, and at this time the third valve 7 may be closed to supply the compressed gas to the heat collection field 1.

The heat collection inlet 15 and the cold salt tank 2 can be communicated through a cold salt pipeline, the cold salt pipeline is provided with a second valve 6, the second valve 6 is kept in an open state when heat collection circulation is performed or salt is dispersed, and the second valve 6 can be closed only when salt dispersion is finished and heat collection circulation is not started. A cold salt pump 8 can be arranged between the second valve 6 and the heat collection inlet 15, and the cold salt pump 8 is used as a main power source during heat collection circulation and is used for providing power for pumping out the molten salt in the cold salt tank 2 and driving the molten salt to reach the hot salt tank 3 after passing through the heat collection field 1 and the cold salt hot tank.

As shown in fig. 2 to 4, in a specific embodiment, a linear fresnel type form may be adopted, for example, the heat collection field 1 may include a plurality of heat collection tubes 13, each heat collection tube 13 corresponds to a corresponding linear fresnel type light-gathering heat collection system, the linear fresnel type light-gathering heat collection system includes a primary reflection mirror 111 and a secondary reflection mirror 121, the primary reflection mirror 111 may be a flat mirror and a plurality of primary reflection mirrors are arranged, the light 14 irradiated to the primary reflection mirror 111 may be reflected to the secondary reflection mirror 121 by adjusting an angle of the primary reflection mirror 111, and the secondary reflection mirror 121 may be a curved surface structure, and the light 14 reflected by the primary reflection mirror 111 is reflected to the heat collection tube 13 again. Because the area of the primary reflecting mirror surface 111 is larger than that of the secondary reflecting mirror surface 121, a larger area of illumination can be used to obtain a larger range of solar energy, and the primary reflecting mirror surface 111 and the secondary reflecting mirror surface 121 are uniformly distributed along the length direction of the heat collecting tube 13, so that the heat collecting tube 13 can be uniformly heated, and the effective utilization of the solar energy by the molten salt in the heat collecting tube 13 is realized. As shown in fig. 3, the primary reflecting mirror structure 11 includes a supporting box 113, the surface of the supporting box 113 is bonded with the primary reflecting mirror 111 through a glue spot 112, and the supporting box 113 can drive the primary reflecting mirror 111 to deflect at an angle under the action of the driving structure, so as to adjust the reflecting direction of the light 14. As shown in fig. 4, the secondary reflector structure 12 includes a supporting frame 122 and a secondary reflector 121 fixedly mounted on the supporting frame 122, the secondary reflector 121 is disposed around an outer periphery of the heat collecting tube 13, and may be in a curved form such as a hyperboloid, and is capable of reflecting the light 14 onto the heat collecting tube 13.

s1: at night or under the condition of insufficient illumination, the fused salt can not obtain enough heat, if the fused salt is not discharged in time, congestion can be caused, and adverse effects are caused to the system, and at the moment, salt dredging operation is needed. When the heat collection is finished and salt dredging is prepared, the cold salt pump 8 is closed firstly, the heat collection molten salt circulation is stopped, and the molten salt starts to flow back to the cold salt tank 2 from the heat collection field 1 under the action of self weight. In the process, the flowability of the molten salt can be improved by obliquely arranging the heat collecting pipes 13 of the heat collecting field 1 (the heat collecting pipes can be fixedly arranged in an inclined state in the early stage, and the inclination angle can also be changed through a tilting driving structure).

S2: after the molten salt flows for a period of time, the molten salt flow speed tends to slow down or stagnate due to factors such as pipe resistance. At this time, the compressed air source 4 can be opened, high-pressure gas is supplemented into the heat collection field 1 through the heat collection outlet 16, the internal pressure of the heat collection field 1 is increased, power for driving molten salt to flow is formed by means of the increase of the internal pressure, and therefore the power for molten salt to flow can be increased on the basis that the molten salt flows by means of self weight.

S3: after the pressure is increased to a certain degree, the compressed air source 4 can be closed, and the molten salt continuously flows back under the action of the existing gas pressure in the heat collection field 1.

S4: along with the flowing of the fused salt, the pressure in the heat collection field 1 is gradually reduced, the driving capability of the fused salt is gradually weakened, the flowing speed is slowed down or stopped again, at the moment, the compressed air source 4 is started again, the step S2 and the step S3 are repeated, and the compressed air is repeatedly supplemented into the heat collection field 1 until the fused salt in the heat collection field 1 is completely discharged.

When the internal pressure of the heat collection field 1 is reduced to be below 0.8MPa, the compressed air source 4 is started, the compressed air source 4 is closed after the pressure is increased to be 0.8MPa, when the pressure is reduced to be below 0.8MPa again, the pipeline pressure is low at the moment, molten salt is difficult to flow, the compressed air source 4 is started again, the pipeline pressure is increased, and the pressure change is observed constantly. The pressure in the heat collection field 1 is maintained at about 0.8MPa, and the pressure limit is set to 0.8MPa, so that the pressure of compressed gas can be fully utilized to promote the flow of molten salt, and the damage to the heat collection field 1 caused by overlarge pressure can be avoided.

When stopping heat collection, the temperature of the molten salt needs to be considered, because the temperature in the cold salt tank 2 is generally around 290 ℃, if the temperature of the cold salt returned into the cold salt tank 2 is too high, the cold salt tank 2 may be damaged. Therefore, after the temperature of the molten salt is reduced to 350 ℃, the circulation of the heat collection molten salt is stopped, and at the moment, the molten salt starts to flow back to the cold salt tank 2 from the heat collection field 1. The molten salt at the temperature has good fluidity and can protect the cold salt tank 2 from being damaged due to overhigh temperature.

In can assisting the quick backward flow of fused salt to cold salt jar 2 through repeated supplementary compressed gas, the initial stage, the fused salt can flow to cold salt jar 2 gradually in the pipeline, compressed gas's replenishment can only increase the pressure in the thermal-collecting tube 13 of thermal-arrest field 1, and can't directly get into cold salt jar 2 through the fused salt, consequently, after confirming that compressed gas reachs cold salt jar 2, can judge that the fused salt in the thermal-arrest field 1 has been arranged totally, can terminate and dredge salt work.

The utility model discloses a concrete example is applied to explain the principle and the implementation mode of the utility model, and the explanation of the above example is only used to help understand the method and the core idea of the utility model; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the concrete implementation and the application scope. In summary, the content of the present specification should not be construed as a limitation of the present invention.

Claims

1. The utility model provides a linear solar energy collection salt dredging system which characterized in that: the system comprises a heat collection field, and a cold salt tank, a hot salt tank and a compressed air source which are respectively communicated with the heat collection field; the cold salt tank is communicated with a heat collection inlet of the heat collection field, and the hot salt tank and the compressed air source are both communicated with a heat collection outlet of the heat collection field; and the compressed air source is used for supplementing high-pressure air into the heat collection field when the salt is dispersed, and increasing the power of the molten salt flowing back to the cold salt tank from the heat collection field.

2. The linear solar thermal collector salt phobic system of claim 1, wherein: the heat collection field is obliquely arranged, and the height of the heat collection inlet is lower than that of the heat collection outlet.

3. The linear solar thermal collection solvophobic system of claim 1 or 2, wherein: the cold salt tank and the hot salt tank are both positioned below the ground level, and the distance between the top of the tank and the ground level is 1-3 m.

4. The linear solar thermal collector salt phobic system of claim 3, wherein: the heat collection outlet is communicated with the hot salt tank through a hot salt pipeline, and a third valve is arranged on the hot salt pipeline.

5. The linear solar thermal collector salt phobic system of claim 4, wherein: the hot salt pipeline is provided with a branch communicated with the compressed air source, and a first valve is arranged on the branch.

6. The linear solar thermal collector salt phobic system of claim 3, wherein: the heat collection inlet is communicated with the cold salt tank through a cold salt pipeline, a second valve is arranged on the cold salt pipeline, and a cold salt pump is arranged between the second valve and the heat collection inlet.

7. The linear solar thermal collector salt phobic system of claim 3, wherein: the solar heat collecting system is characterized in that the heat collecting field adopts a linear Fresnel type light-gathering heat collecting system, the linear Fresnel type light-gathering heat collecting system comprises a primary reflecting mirror surface and a secondary reflecting mirror surface, incident light is reflected to the secondary reflecting mirror surface through the primary reflecting mirror surface, the secondary reflecting mirror surface irradiates the reflected light to the heat collecting tube of the heat collecting field, and the area of the primary reflecting mirror surface is larger than that of the secondary reflecting mirror surface.