CN109856182A - A kind of measurement method and system of fused salt heat dump tube panel absorptivity - Google Patents
A kind of measurement method and system of fused salt heat dump tube panel absorptivity Download PDFInfo
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- CN109856182A CN109856182A CN201910114324.0A CN201910114324A CN109856182A CN 109856182 A CN109856182 A CN 109856182A CN 201910114324 A CN201910114324 A CN 201910114324A CN 109856182 A CN109856182 A CN 109856182A
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- 150000003839 salts Chemical class 0.000 title claims abstract description 182
- 238000000691 measurement method Methods 0.000 title claims abstract 10
- 238000010521 absorption reaction Methods 0.000 claims abstract description 58
- 238000004088 simulation Methods 0.000 claims abstract description 25
- 238000005259 measurement Methods 0.000 claims abstract description 16
- 230000005855 radiation Effects 0.000 claims abstract description 11
- 230000004907 flux Effects 0.000 claims abstract description 5
- 239000006096 absorbing agent Substances 0.000 claims description 102
- 238000012360 testing method Methods 0.000 claims description 32
- 238000004364 calculation method Methods 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 22
- 230000017525 heat dissipation Effects 0.000 claims description 21
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 238000002834 transmittance Methods 0.000 claims description 10
- 238000002310 reflectometry Methods 0.000 claims description 8
- 230000003749 cleanliness Effects 0.000 claims description 6
- 238000012546 transfer Methods 0.000 claims description 6
- 238000004422 calculation algorithm Methods 0.000 claims description 3
- 238000010248 power generation Methods 0.000 description 8
- 239000011241 protective layer Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 241000282414 Homo sapiens Species 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 238000003915 air pollution Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000005338 heat storage Methods 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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- Y02E10/40—Solar thermal energy, e.g. solar towers
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Abstract
The invention discloses the measurement method and system of a kind of single tube panel absorptivity of fused salt heat dump, which includes energy-flux density simulation subsystem, flow rate of molten salt meter, fused salt heat dump tube panel inlet and outlet temperature of molten salt measuring device, infrared radiation thermometer, wind speed and temperature measuring device etc..The measurement method is as follows: to some tube panel to be measured, it is assumed that absorptivity α obtains the ENERGY E projected on the heat dump tube panel by energy-flux density simulation subsystem when fused salt heat dump operates normallyt, this makes it possible to obtain the received gross energy α E of the heat dump tube panelt, the Temperature Distribution on heat dump tube panel is obtained by infrared radiation thermometer, in addition total radiation loss L on fused salt heat dump is calculated in measured ambient wind velocity and environment temperature, fused salt flux in heat dump tube panel is measured by flow rate of molten salt measurementIn addition the ENERGY E of fused salt actual absorption in single heat dump tube panel can be calculated in heat dump tube panel out temperaturer, then fused salt heat dump tube panel absorptivity α=(E for being surveyedr+L)/Et。
Description
Technical Field
The invention relates to a solar tower type molten salt thermal power generation system, in particular to measurement of tube panel absorption rate of a molten salt heat absorber.
Background
The solar high-temperature thermal power generation technology is an important development direction for large-scale utilization of solar energy and has profound significance for solving the problems of fossil energy crisis, air pollution and the like for human beings. There are various technical directions for solar high-temperature thermal power generation: according to the difference of focusing modes, the method can be divided into a tower mode, a groove mode and a disc mode. Among them, the tower type and the tank type are mainly used in large-scale commercial application. Compared with the groove type, the tower type solar cell has higher light gathering ratio, can reach higher use temperature and has higher general power generation efficiency. In addition, in the aspect of energy storage, if the fused salt is adopted for heat storage, the temperature utilization interval of the tower type is about 3 times of that of the tank type, so that the cost of the tower type energy storage is lower. The working medium of the tower-type heat absorber mainly comprises water (steam), molten salt, air, liquid metal and the like. The fused salt can absorb heat and store heat integrally, and the commercial operation of the foreign fused salt power station is realized at present, so the fused salt tower type solar power station is an important direction for large-scale commercial application in the field of solar thermal power generation in the future.
The molten salt heat absorber is a key device for converting solar radiation energy into molten salt heat energy. In order to improve the heat absorption efficiency of the molten salt, a high-absorptivity coating is plated on the surface of the heat absorber. The existing mature fused salt heat absorber coating mainly comprises Pyromark2500, the service temperature of the coating can reach over 1000 ℃, and the absorptivity of the fused salt heat absorber coated by a strict process can reach over 0.95. The high absorption rate can greatly improve the overall heat efficiency of the molten salt heat absorber, and the absorption rate index is one of core indexes of the molten salt heat absorber.
The absorptivity of the coating of the fused salt heat absorber can be reduced along with the increase of the service life, and in addition, the fused salt heat absorber running outdoors for a long time cannot avoid being subjected to dust adhesion, abrasion and erosion, so that the absorptivity is reduced. In addition, the fused salt valve occasionally has salt leakage accidents and stains the light receiving surface of the heat absorption tube panel due to reasons such as reduced sealing performance, the heat absorption tube can also have tube explosion accidents to stain the light receiving surface of the heat absorption tube panel, and the absorptivity of the polluted heat absorption tube panel can be rapidly reduced, so that the heat absorption efficiency is influenced.
Measuring the tube panel absorption rate of the fused salt heat absorber is an important and extremely difficult task. The absorption rate of a heat absorption pipe with small pipe diameter and certain curvature cannot be measured by a conventional measuring instrument; in addition, high-altitude and large-area measurement operation has great safety risk and measurement difficulty. Therefore, developing a simple-to-operate method for measuring the tube panel absorption rate of the molten salt heat absorber is an important and urgent task in a solar tower-type molten salt heat power generation system.
Disclosure of Invention
The invention provides a method and a system for measuring the tube panel absorption rate of a molten salt heat absorber. The measuring method and the measuring system can indirectly measure the absorption rate of a single tube panel of the molten salt heat absorber, so that an accurate basis is provided for the coating replacement period and the heat absorber efficiency calculation.
The technical scheme of the invention is as follows:
a method for measuring the tube panel absorption rate of a molten salt heat absorber comprises the steps of providing a measuring system, wherein the system comprises a power flow density simulation subsystem, a molten salt flowmeter, a molten salt temperature measuring device at an inlet/outlet of a tube panel of the molten salt heat absorber, an infrared thermometer and a wind speed and temperature measuring device, wherein the power flow density simulation subsystem is used for calculating energy projected to a single tube panel; the mass flow of the molten salt is measured through the molten salt flowmeter, the temperature of the molten salt at the outlet and the inlet of the heat absorber is measured through the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber, so that the enthalpy value of the molten salt is obtained, and the data measured by the molten salt flowmeter and the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber are used for calculating to obtain the energy absorbed by the molten salt in the tube panel; measuring the average temperature of the light side wall surface of the measured tube panel by the infrared thermometer, measuring the ambient wind speed and temperature by the wind speed and temperature measuring device, and calculating the data measured by the infrared thermometer and the wind speed and temperature measuring device to obtain the total heat dissipation loss of the tube panel; the measuring method obtains the absorptivity of the tube panel to be measured through calculation of the energy projected to a single tube panel, the energy absorbed by molten salt in the tube panel and the total heat dissipation loss of the tube panel.
The calculation formula of the energy absorbed by the molten salt is as follows:
whereinThe mass flow of the molten salt at the inlet of the molten salt heat absorber is measured by a molten salt flowmeter; h isoutThe enthalpy value of fused salt at the outlet of the heat absorber; h isinThe enthalpy value of fused salt at the inlet of the fused salt heat absorber is obtained by a fused salt temperature measuring device at the inlet/outlet of a tube panel of the fused salt heat absorber.
In order to obtain accurate molten salt absorbed energy, the flow rate of the molten salt and the temperature of the molten salt at the inlet/outlet of the heat absorber need to be relatively stable. Therefore, the fluctuation of the molten salt flow in the test period needs to be less than 15%, and the fluctuation of the molten salt temperature of the inlet and the outlet of the tube panel of the molten salt heat absorber needs to be less than 15 ℃.
In order to keep the energy supply and heat dissipation losses of the mirror field relatively stable, it is necessary to ensure that the DNI during the test is greater than 700KW/m in consideration of the relation between the projection energy of the mirror field and the direct radiation energy DNI, the availability of the mirror field and the efficiency of the mirror field2And the fluctuation range is not suitable to exceed 50KW/m2(ii) a The availability ratio of the mirror field during the test is more than 90 percent; the mirror field efficiency is generally stable within 3 hours around noon, so the recommended test time period is within 3 hours around noon. The heat dissipation loss of the heat absorber is mainly related to the wind speed, and in order to reduce the test error, the wind speed during the test is required to be less than 6 m/s.
Generally, the greater the energy absorbed by the heat sink, the greater the accuracy of the test, and therefore it is recommended that the energy absorbed by the heat sink during the test be maintained at least above 85% of the rated energy. Therefore, a specular cleanliness of greater than 85% is recommended when testing.
The mirror field of a certain region of the heat absorption tower shadow can be greatly reduced to project energy, so that the mirror field of the heat absorber tube panel corresponding to the region can project energy which does not meet the test requirement, and therefore the absorption rate of the heat absorber tube panel is not measured when the heat absorber tube panel is shielded by the heat absorption tower shadow. Since the position of the sun changes over time, the absorptance of all heat absorber tube panels can be measured by adjusting the test time period.
The energy flux density simulation subsystem can calculate the energy E projected to a single tube paneltThe calculation formula is as follows:
Et＝DNI×S×N×ηt×ηcos×ηs×ηb×ηc×ηr×ηtruc
wherein DNI is direct radiation energy which can be directly measured by a DNI instrument, S is the area of solar energy which can be reflected by a single heliostat, N is the total number of heliostats projected to a measured tube panel, ηtη being atmospheric transmittancecosIs cosine efficiency ηsFor shadow efficiency ηbη for efficiency of shadingcη for mirror surface cleanlinessrη being the reflectivity of the mirror fieldtrucThe cutoff efficiency of the tube panel to be measured.
Wherein atmospheric transmittance ηtCosine efficiency ηcosShadow efficiency ηsShielding efficiency ηbAnd cutoff efficiency ηtrucCan be directly simulated and calculated by a mature algorithm, and the main input parameters of the simulation calculation method are the coordinates of all heliostats in a heliostat field, the vertex coordinates of a measured tube panel and the cleanness of the mirror surface ηcAnd mirror field reflectivity ηrIt needs to be measured out.
In general, the cosine efficiency, the shadow efficiency and the shielding efficiency can be subjected to more accurate simulation calculation through verified codes; the cleanliness of the mirror surface and the reflectivity of the mirror field need to be obtained through measurement; the atmospheric transmittance and the truncation efficiency can only be obtained through simulation calculation at present, but the accuracy is difficult to verify, the atmospheric transmittance is related to particles and gas components in the air, the truncation efficiency is related to the mean error of the heliostat, and the two efficiencies are usually reflected to be larger or smaller as a whole when the calculation is carried out through given parameters.
The total heat dissipation loss includes convection loss, radiation loss and heat conduction loss. Wherein the heat conduction loss is negligible due to the small occupation ratio. The calculation formula of the total heat dissipation loss is as follows:
wherein: h is a convective heat transfer coefficient, mainly related to the ambient wind speed and the normal angle of the tested tube panel, and needs to be actually measured, if actual measurement data are lacked, the convective heat transfer coefficient can be 10-60W/(m) when the wind speed is less than 6m/s during the test period2K) A value in between; a is the light receiving area of the tube screen to be measured, and the unit m2；The average temperature of the illuminated surface of the tube screen is measured in K, and the average temperature can be directly measured by an infrared thermometer; t is0Is ambient temperature, in K; epsilon is the emissivity of the tube screen to be measured, needs to be provided by a coating manufacturer, and can be 0.90 when no data exists; σ is Boltzmann constant.
The absorption rate of the tube panel to be measured is calculated according to the formula of α ═ (E)r+L)/Et
The sub-efficiency of the mirror field inevitably has certain error in the simulation calculation, thereby causing certain error in the absorption rate measurement result. In this case, the method provided by the invention is particularly suitable for measuring the relative absorption rate of the tube panel of the molten salt heat absorber.
The invention provides a method for measuring the relative absorptivity of a tube panel of a molten salt heat absorber, wherein the absorptivity of 2 tube panels measured by the molten salt heat absorber is respectively set to be α and α ', α and α ' are respectively calculated by the method, and then the relative absorptivity of the 2 tube panels is calculated by α/α '.
The invention also provides a system for measuring the tube panel absorption rate of the molten salt heat absorber, which comprises an energy flow density simulation subsystem, a molten salt flowmeter, a molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber, an infrared thermometer and a wind speed and temperature measuring device, wherein the energy flow density simulation subsystem is used for calculating to obtain the energy projected to a single tube panel; the molten salt flow meter is used for measuring the mass flow of molten salt, the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber is used for measuring the temperature of molten salt at the outlet and the inlet of the heat absorber so as to obtain an enthalpy value, and data measured by the molten salt flow meter and the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber are used for calculating to obtain the energy absorbed by the molten salt in the tube panel; the infrared thermometer is used for measuring the wall surface temperature of the heat absorber, the wind speed and temperature measuring device is respectively used for measuring the ambient wind speed and the ambient temperature, and data measured by the infrared thermometer and the wind speed and temperature measuring device are used for calculating to obtain the total heat dissipation loss of the tube panel; the absorption rate of the tube panel to be detected can be calculated through the energy projected to the single tube panel, the energy absorbed by the molten salt in the tube panel and the total heat dissipation loss of the tube panel.
Compared with the prior art, the invention has the following beneficial effects:
the measuring method and the measuring system provided by the invention can indirectly measure the absorption rate of a single tube panel of the molten salt heat absorber, thereby providing an accurate basis for the replacement cycle of the coating and the efficiency calculation of the heat absorber.
Of course, it is not necessary for any product in which the invention is practiced to achieve all of the above-described advantages at the same time.
Drawings
FIG. 1 is a schematic diagram of a tower-type solar thermal power generation system;
FIG. 2 is a profile view of an external molten salt heat absorber;
FIG. 3 is a profile view of a cavity-type molten salt heat absorber;
FIG. 4 is a schematic view of a single tube panel;
FIG. 5 is a flowchart of measuring absorption rate of the panel in example 1 of the present invention;
reference numerals: 1. an upper protective layer; 2. combining the heat absorber tube panels; 3. a lower protective layer; 4. feeding a molten salt header; 5. a heat absorbing tube; 6. and (4) a lower molten salt header.
Detailed Description
The invention discloses a method and a system for measuring the absorption rate of a single tube panel of a fused salt heat absorber, wherein the system comprises a power flow density simulation subsystem, a fused salt flowmeter, a fused salt temperature measuring device for the inlet and the outlet of the tube panel of the fused salt heat absorber, an infrared thermometer, a wind speed and temperature measuring device and the liketTherefore, total energy α E received by the heat absorber tube panel can be obtainedtObtaining the temperature distribution on the tube panel of the heat absorber through an infrared thermometer, calculating the total heat dissipation loss L on the fused salt heat absorber by adding the measured ambient wind speed and ambient temperature, and obtaining the flux of the fused salt in the tube panel of the heat absorber through the measurement of a fused salt flowmeterThe temperature of the inlet and the outlet of the heat absorber tube panel can be calculated to obtain the energy E actually absorbed by the molten salt in the single heat absorber tube panelrThe measured absorption rate of the fused salt heat absorber tube panel α ═ E (E)r+L)/Et。
For a better understanding of the present invention, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
Example 1
As shown in fig. 1, a tower-type solar thermal power station drives a large number of heliostats to track sunlight, so that the sunlight is collected on the surface of a heat absorber positioned at the top end of the heat absorber, and heats a heat absorbing medium, so that light energy is converted into heat energy, and the heat energy is converted into electric energy, thereby realizing solar thermal power generation.
As shown in fig. 2, the external structure of the conventional external molten salt heat absorber mainly comprises an upper protective layer (1), a heat absorbing panel (2) and a lower protective layer (3). Wherein, the heat absorption panel (2) encloses 360 degrees and can receive the solar radiation energy reflected all around.
Fig. 3 shows the outline of the cavity molten salt heat absorber. The cavity absorber is generally open downward and thus the acceptance angle is somewhat limited.
A schematic of a single tube panel is shown in fig. 4. The single tube panel comprises an upper molten salt header (4), a heat absorption tube combination (5), a lower molten salt header (6) and the like (the tube panel also comprises structures such as electric heat tracing, heat preservation, an oven and a supporting steel frame, which are not shown in the figure). The molten salt can flow into the lower molten salt header from the upper molten salt header or can flow in the reverse direction. The fused salt temperature of the inlet and the outlet of the tube panel can be measured through the fused salt header.
Fig. 5 is a block diagram of a method for measuring the absorption rate of a panel, including blocks S1, S2, S3, and S4, in which,
step S1 is: simulating energy E projected onto a single tube panel of a heat absorbert；
Step S2 is: calculating the total heat dissipation loss L according to the temperature measured by the light-receiving side wall surface of the tube panel, the ambient wind speed and the temperature;
step S3 is: calculating the actual absorption energy E of the molten salt in the tube panel through the flow rate of the molten salt measured by the tube panel and the temperature of the inlet and the outlet saltr；
Step S4 is: and calculating the tube panel absorption rate according to the listed formula according to the parameters obtained in the steps S1, S2 and S3.
Wherein, step S1 specifically includes:
calculated according to the following calculation formula:
Et＝DNI×S×N×ηt×ηcos×ηs×ηb×ηc×ηr×ηtruc
wherein DNI is direct radiant energy; s is aThe area of each heliostat capable of reflecting solar energy, N is the total number of the heliostats projected to the measured tube panel, ηtη being atmospheric transmittancecosIs cosine efficiency ηsFor shadow efficiency ηbη for efficiency of shadingcη for mirror surface cleanlinessrη being the reflectivity of the mirror fieldtrucThe cutoff efficiency of the tube panel to be measured.
Wherein,
DNI can be measured directly by a DNI meter; s and N can be directly obtained through monitoring software.
Atmospheric transmittance, cosine efficiency, shadow efficiency, shielding efficiency and truncation efficiency can be directly calculated by simulation through a mature algorithm, and the main input parameters of the simulation are coordinates of all heliostats in a mirror field and vertex coordinates of a measured tube panel; the cleanness of the mirror surface and the reflectivity of the mirror field can be directly measured by related instruments.
In general, the cosine efficiency, the shadow efficiency and the shielding efficiency can be subjected to more accurate simulation calculation through verified codes; the cleanliness of the mirror surface and the reflectivity of the mirror field need to be obtained through measurement; the atmospheric transmittance and the truncation efficiency can only be obtained through simulation calculation at present, but the accuracy is difficult to verify, the atmospheric transmittance is related to particles and gas components in the air, the truncation efficiency is related to the mean error of the heliostat, and the two efficiencies are usually reflected to be larger or smaller as a whole when the calculation is carried out through given parameters.
Step S2 specifically includes:
the total heat dissipation loss includes convection loss, radiation loss and heat conduction loss. Wherein the heat conduction loss is negligible due to the small occupation ratio. The calculation formula of the total heat dissipation loss is as follows:
wherein: h is the convective heat transfer coefficient, mainly related to the ambient wind speed and the normal angle of the tube panel to be measuredThe degree is related, actual measurement is needed, if actual measurement data are lacked, the convective heat transfer coefficient can be 10-60W/(m) when the wind speed is less than 6m/s during the test period2K) A value in between; a is the light receiving area of the tube screen to be measured, and the unit m2；The average temperature of the light-receiving side wall surface of the tube panel to be measured is in unit K, and the average temperature can be directly measured by an infrared thermometer; t is0Is ambient temperature, in K; epsilon is the emissivity of the tube screen to be measured, needs to be provided by a coating manufacturer, and can be 0.90 when no data exists; σ is Boltzmann constant. Wherein,
the ambient wind speed can be measured by a wind speed measuring device, the ambient temperature can be measured by a temperature measuring device, and the wind speed measuring device and the temperature measuring device can be integrated or arranged separately.
Step S3 specifically includes:
the energy absorbed by the molten salt is calculated according to the following calculation formula:
whereinMeasuring the mass flow of molten salt at the inlet of the molten salt heat absorber by using a molten salt flowmeter; h isoutThe enthalpy value of fused salt at the outlet of the heat absorber; h isinThe enthalpy value of fused salt at the inlet of the fused salt heat absorber is measured by a fused salt temperature measuring device at the inlet/outlet of a tube panel of the fused salt heat absorber.
In order to obtain accurate molten salt absorbed energy, the flow rate of the molten salt and the temperature of the molten salt at the inlet/outlet of the heat absorber need to be relatively stable. Therefore, the fluctuation of the molten salt flow in the test period needs to be less than 15%, and the fluctuation of the molten salt temperature of the inlet and the outlet of the tube panel of the molten salt heat absorber needs to be less than 15 ℃.
To make the mirror field portableThe energy supply and heat dissipation losses are kept relatively stable, and the DNI needs to be more than 700KW/m during the test period considering that the projection energy of the mirror field is related to DNI, the availability ratio of the mirror field and the efficiency of the mirror field2And the fluctuation range is not suitable to exceed 50KW/m2(ii) a The availability ratio of the mirror field during the test is more than 90 percent; the mirror field efficiency is generally stable within 3 hours around noon, so the recommended test time period is within 3 hours around noon. The heat dissipation loss of the heat absorber is mainly related to the wind speed, and in order to reduce the test error, the wind speed during the test is required to be less than 6 m/s.
Generally, the greater the energy absorbed by the heat sink, the greater the accuracy of the test, and therefore it is recommended that the energy absorbed by the heat sink during the test be maintained at least above 85% of the rated energy. Therefore, a specular cleanliness of greater than 85% is recommended when testing.
The mirror field of a certain region of the heat absorption tower shadow can be greatly reduced to project energy, so that the mirror field of the heat absorber tube panel corresponding to the region can project energy which does not meet the test requirement, and therefore the absorption rate of the heat absorber tube panel is not measured when the heat absorber tube panel is shielded by the heat absorption tower shadow. Since the position of the sun changes over time, the absorptance of all heat absorber tube panels can be measured by adjusting the test time period.
Step S4 includes:
the absorption rate of the tube panel is calculated according to the calculation formula shown, wherein α is equal to (E)r+L)/Et
Particularly, certain errors inevitably exist in the mirror field fractional efficiency during simulation calculation, so that certain errors exist in the absorption rate measurement result. In this case, the method provided by the invention is particularly suitable for measuring the relative absorption rate of the tube panel of the molten salt heat absorber.
The method for measuring the relative absorption rate of the tube panel of the molten salt heat absorber provided by the embodiment specifically comprises the steps of setting the absorption rates of 2 tube panels measured by the molten salt heat absorber to be α and α ', respectively calculating α and α ' through the method, and then calculating the relative absorption rates of the 2 tube panels through α/α '.
Example 2
The embodiment provides a system for measuring the tube panel absorption rate of a fused salt heat absorber, which comprises an energy flow density simulation subsystem, a fused salt flowmeter, a fused salt temperature measuring device for the inlet/outlet of a fused salt heat absorber tube panel, an infrared thermometer and a wind speed and temperature measuring device, wherein the energy flow density simulation subsystem is used for calculating to obtain the energy projected to a single tube panel; the fused salt flowmeter is used for measuring the mass flow of fused salt, the fused salt temperature measuring device at the inlet/outlet of the fused salt heat absorber tube panel is used for measuring the fused salt enthalpy value at the outlet and the inlet of the heat absorber, and data measured by the fused salt flowmeter and the fused salt temperature measuring device at the inlet/outlet of the fused salt heat absorber tube panel are used for calculating to obtain the energy absorbed by the fused salt in the tube panel; the infrared thermometer is used for measuring the wall surface temperature of the heat absorber, the wind speed and temperature measuring device is respectively used for measuring the ambient wind speed and the ambient temperature, and data measured by the infrared thermometer and the wind speed and temperature measuring device are used for calculating to obtain the total heat dissipation loss of the tube panel; the absorption rate of the tube panel to be detected can be calculated through the energy projected to the single tube panel, the energy absorbed by the molten salt in the tube panel and the total heat dissipation loss of the tube panel.
The measuring method and the measuring system provided by the invention can indirectly measure the absorption rate of a single tube panel of the molten salt heat absorber, thereby providing an accurate basis for the replacement cycle of the coating and the efficiency calculation of the heat absorber.
The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims (11)
1. A method for measuring the tube panel absorption rate of a molten salt heat absorber is characterized by comprising the following steps:
providing a test system, wherein the test system comprises an energy flow density simulation subsystem, a molten salt flowmeter, a molten salt temperature measuring device for an inlet and an outlet of a tube panel of a molten salt heat absorber, an infrared thermometer and a wind speed and temperature measuring device;
the energy projected to a single tube panel is calculated by the energy flux density simulation subsystem,
measuring mass flow of molten salt through the molten salt flowmeter, measuring the temperature of an outlet and an inlet of the heat absorber through the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber to obtain an enthalpy value of the molten salt, and calculating the energy absorbed by the molten salt in the tube panel through the data measured by the molten salt flowmeter and the molten salt temperature measuring device at the inlet/outlet of the tube panel of the molten salt heat absorber;
measuring the average temperature of the light side wall surface of the measured tube panel by the infrared thermometer, measuring the ambient wind speed and temperature by the wind speed and temperature measuring device, and calculating the total heat dissipation loss of the tube panel by the data measured by the infrared thermometer and the wind speed and temperature measuring device;
and calculating the absorption rate of the tube panel according to the energy projected to the single tube panel, the energy absorbed by the molten salt in the tube panel and the total heat dissipation loss of the tube panel.
2. The measurement method according to claim 1, wherein the energy absorbed by the molten salt in the tube panel is calculated as follows:
wherein,the mass flow of the molten salt at the inlet of the molten salt heat absorber is measured by the molten salt flowmeter; h isoutThe enthalpy value of fused salt at the outlet of the heat absorber hinThe enthalpy value of fused salt at the inlet of the fused salt heat absorber is obtained by the fused salt temperature measuring device at the inlet and the outlet of the tube panel of the fused salt heat absorber.
3. The measurement method according to claim 1, characterized in that the following requirements are placed on the test environment: direct radiation energy requirement during testing of more than 700KW/m2And needs to remain substantially stable; the wind speed during the test is required to be less than 6 m/s.
4. The measurement method according to claim 1, characterized in that the following requirements are placed on the stability of the test data: in the test period, the fluctuation of the molten salt flow is required to be less than 15%, and the fluctuation of the molten salt temperature of the inlet and outlet of the tube panel of the molten salt heat absorber is required to be less than 15 ℃.
5. The measurement method of claim 2, wherein the energy flux density simulation subsystem calculates the energy projected to a single tube panel using the following calculation:
Et＝DNI×S×N×ηt×ηcos×ηs×ηb×ηc×ηr×ηtruc
wherein DNI is direct radiation energy, S is the area of solar energy reflected by a single heliostat, N is the total number of heliostats projected to the measured tube panel, ηtη being atmospheric transmittancecosIs cosine efficiency ηsFor shadow efficiency ηbη for efficiency of shadingcη for mirror surface cleanlinessrη being the reflectivity of the mirror fieldtrucThe truncation efficiency of the measured tube panel;
wherein atmospheric transmittance ηtCosine efficiency ηcosShadow efficiency ηsShielding efficiency ηbAnd cutoff efficiency ηtrucThe method comprises the steps of directly simulating and calculating by a mature algorithm, directly measuring DNI (DNI) by a DNI measuring instrument according to main input parameters of coordinates of all heliostats in a heliostat field and coordinates of four corners and vertexes of a measured tube panel, directly reading the total number N of the heliostats projected to the measured tube panel by monitoring software, and η the cleanliness of a mirror surfacecAnd mirror field reflectivity ηrAre obtained for the measurement.
6. A method of measurement according to claim 5, characterized by the fact that the mirror cleanliness ηcThe following requirements are met: the cleanness of the mirror surface is more than 85 percent.
7. The measurement method according to claim 5, wherein the energy flow density simulation subsystem must consider the influence of a heat absorption tower shadow, and the heat absorber tube panel absorption rate is not measured during the period when the heat absorber tube panel is shielded by the heat absorption tower shadow.
8. The measurement method according to claim 5, wherein the calculation formula of the total heat dissipation loss is as follows:
wherein: h is a convective heat transfer coefficient, mainly related to the ambient wind speed and the normal angle of the tested tube panel, and needs to be actually measured, if actual measurement data is lacked, the wind speed during the test period needs to be less than 6m/s, and the convective heat transfer coefficient can be 10-60W/(m)2K) A value in between; a is the light receiving area of the tube screen to be measured, and the unit m2；The average temperature of the light-receiving side wall surface of the tube panel is measured in unit K, and the average temperature is directly measured by an infrared thermometer; t is0Is ambient temperature, in K; epsilon is the emissivity of the tube screen to be measured and is provided by a coating manufacturer, or can be 0.90 when no data exists; σ is Boltzmann constant.
9. The method of measurement according to claim 8, wherein the measured screen absorption α is calculated by the formula:
α＝(Er+L)/Et。
10. the measurement method according to claim 8 is particularly suitable for measuring the relative absorption rate of the tube panel of the molten salt heat absorber, wherein the absorption rate of 2 tube panels of the molten salt heat absorber is set to be α and α 'respectively, and then the relative absorption rate of the 2 tube panels is α/α'.
11. The system for measuring the tube panel absorption rate of the molten salt heat absorber is characterized by comprising an energy flow density simulation subsystem, a molten salt flowmeter, a molten salt temperature measuring device for an inlet/outlet of the tube panel of the molten salt heat absorber, an infrared thermometer and a wind speed and temperature measuring device, wherein the energy flow density simulation subsystem is used for calculating to obtain energy projected to a single tube panel; the fused salt flowmeter is used for measuring the mass flow of fused salt, the fused salt temperature measuring device at the inlet/outlet of the fused salt heat absorber tube panel is used for measuring the fused salt temperature at the outlet and the inlet of the heat absorber, and data measured by the fused salt flowmeter and the fused salt temperature measuring device at the inlet/outlet of the fused salt heat absorber tube panel are used for calculating to obtain the energy absorbed by the fused salt in the tube panel; the infrared thermometer is used for measuring the average temperature of the light side wall surface of the tube panel, the wind speed and temperature measuring device is used for measuring the ambient wind speed and temperature, and the data measured by the infrared thermometer and the data measured by the wind speed and temperature measuring device are used for calculating to obtain the total heat dissipation loss of the tube panel; the absorption rate of the tube panel to be detected can be calculated through the energy projected to the single tube panel, the energy absorbed by the molten salt in the tube panel and the total heat dissipation loss of the tube panel.
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| CN113758032A (en) * | 2021-08-30 | 2021-12-07 | 浙江高晟光热发电技术研究院有限公司 | Cavity type heat absorber and heat absorbing and storing system |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101865814A (en) * | 2010-04-02 | 2010-10-20 | 上海工程技术大学 | Thermal barrier coating layer high-temperature resistance molten salt corrosion test method and device |
| CN102331793A (en) * | 2011-07-19 | 2012-01-25 | 南京科远自动化集团股份有限公司 | Method for scheduling heliostat field in tower solar thermal power station |
| CN102494871A (en) * | 2011-12-08 | 2012-06-13 | 山东力诺新材料有限公司 | Method for testing ageing of vacuum high-temperature solar collector tube |
| CN102590295A (en) * | 2011-01-06 | 2012-07-18 | 通用电气公司 | Corrosion sensor and method for manufacturing a corrosion sensor |
| US20160056759A1 (en) * | 2014-08-21 | 2016-02-25 | Spinlectrix, Inc. | Photovoltaic energy sources |
| CN106932431A (en) * | 2015-12-29 | 2017-07-07 | 北京有色金属研究总院 | A kind of online heat waste test system of slot type high-temperature vacuum heat-collecting tube and method |
| CN107843348A (en) * | 2017-12-14 | 2018-03-27 | 东方电气集团东方锅炉股份有限公司 | A kind of heat dump energy-flux density measurement apparatus and measuring method |
| CN108548336A (en) * | 2018-02-28 | 2018-09-18 | 上海锅炉厂有限公司 | A kind of wind-proof device for tower type solar heat dump |
| CN108917205A (en) * | 2017-03-29 | 2018-11-30 | 考克利尔维修工程有限责任公司 | Heat-machinery monitoring system and method for solar receiver |
-
2019
- 2019-02-14 CN CN201910114324.0A patent/CN109856182B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101865814A (en) * | 2010-04-02 | 2010-10-20 | 上海工程技术大学 | Thermal barrier coating layer high-temperature resistance molten salt corrosion test method and device |
| CN102590295A (en) * | 2011-01-06 | 2012-07-18 | 通用电气公司 | Corrosion sensor and method for manufacturing a corrosion sensor |
| CN102331793A (en) * | 2011-07-19 | 2012-01-25 | 南京科远自动化集团股份有限公司 | Method for scheduling heliostat field in tower solar thermal power station |
| CN102494871A (en) * | 2011-12-08 | 2012-06-13 | 山东力诺新材料有限公司 | Method for testing ageing of vacuum high-temperature solar collector tube |
| US20160056759A1 (en) * | 2014-08-21 | 2016-02-25 | Spinlectrix, Inc. | Photovoltaic energy sources |
| CN106932431A (en) * | 2015-12-29 | 2017-07-07 | 北京有色金属研究总院 | A kind of online heat waste test system of slot type high-temperature vacuum heat-collecting tube and method |
| CN108917205A (en) * | 2017-03-29 | 2018-11-30 | 考克利尔维修工程有限责任公司 | Heat-machinery monitoring system and method for solar receiver |
| CN107843348A (en) * | 2017-12-14 | 2018-03-27 | 东方电气集团东方锅炉股份有限公司 | A kind of heat dump energy-flux density measurement apparatus and measuring method |
| CN108548336A (en) * | 2018-02-28 | 2018-09-18 | 上海锅炉厂有限公司 | A kind of wind-proof device for tower type solar heat dump |
Non-Patent Citations (4)
| Title |
|---|
| ANTONAIA, A. 等: "Accelerated Aging Tests on ENEA-ASE Solar Coating for Receiver Tube Suitable to Operate Up to 550℃", 《21ST INTERNATIONAL CONFERENCE ON CONCENTRATING SOLAR POWER AND CHEMICAL ENERGY SYSTEMS (SOLARPACES 2015)》 * |
| 张茂龙: "塔式太阳能—燃煤双源耦合发电系统分析", 《中国博士学位论文全文数据库 工程科技Ⅱ辑》 * |
| 文玉良 等: "聚光太阳能热发电中吸热器吸收涂层的选择", 《太阳能学报》 * |
| 李培娟: "塔式太阳能吸热器的热工数值模拟", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113758032A (en) * | 2021-08-30 | 2021-12-07 | 浙江高晟光热发电技术研究院有限公司 | Cavity type heat absorber and heat absorbing and storing system |
| CN113758032B (en) * | 2021-08-30 | 2023-12-12 | 浙江高晟光热发电技术研究院有限公司 | Cavity type heat absorber and heat absorbing and storing system |
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