CN112648752A - Method for descaling heat collection device through liquid level difference - Google Patents

Method for descaling heat collection device through liquid level difference Download PDF

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Publication number
CN112648752A
CN112648752A CN201910959856.4A CN201910959856A CN112648752A CN 112648752 A CN112648752 A CN 112648752A CN 201910959856 A CN201910959856 A CN 201910959856A CN 112648752 A CN112648752 A CN 112648752A
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heat
pipe
liquid level
tube
electric heater
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CN112648752B (en
Inventor
侯钦鹏
吴丹淼
齐宾
廉根宽
卓超杰
滕一诺
王铁信
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Qingdao Baiteng Technology Co ltd
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Qingdao Baiteng Technology Co ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S20/00—Solar heat collectors specially adapted for particular uses or environments
    • F24S20/40—Solar heat collectors combined with other heat sources, e.g. using electrical heating or heat from ambient air
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S10/00—Solar heat collectors using working fluids
    • F24S10/70—Solar heat collectors using working fluids the working fluids being conveyed through tubular absorbing conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S40/00—Safety or protection arrangements of solar heat collectors; Preventing malfunction of solar heat collectors
    • F24S40/20—Cleaning; Removing snow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S50/00—Arrangements for controlling solar heat collectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/60—Details of absorbing elements characterised by the structure or construction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S70/00—Details of absorbing elements
    • F24S70/60—Details of absorbing elements characterised by the structure or construction
    • F24S2070/62—Heat traps
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers
    • Y02E10/44—Heat exchange systems

Abstract

The invention provides a method for descaling a heat collection device by liquid level difference, wherein an electric heater is arranged in a heat collection tube box, the electric heater runs at night, a liquid level detection element is in data connection with a controller, the controller extracts liquid level data according to a time sequence and obtains the accumulation of the liquid level difference or the change of the liquid level difference through the comparison of the liquid level data in adjacent time periods, and when the liquid level difference or the change of the liquid level difference is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating. The invention judges the stable state of the fluid according to the liquid level difference or the accumulation of the change of the liquid level difference, so that the result is more accurate, and the problem of error increase caused by aging due to the problem of operation time is solved.

Description

Method for descaling heat collection device through liquid level difference
Technical Field
The invention belongs to the field of solar energy, and particularly relates to a solar heat collector system.
Background
With the rapid development of modern socioeconomic, the demand of human beings on energy is increasing. However, the continuous decrease and shortage of traditional energy reserves such as coal, oil, natural gas and the like causes the continuous increase of price, and the environmental pollution problem caused by the conventional fossil fuel is more serious, which greatly limits the development of society and the improvement of the life quality of human beings. Energy problems have become one of the most prominent problems in the modern world. Therefore, the search for new energy sources, especially clean energy sources without pollution, has become a hot spot of research.
Solar energy is inexhaustible clean energy and has huge resource amount, and the total amount of solar radiation energy collected on the surface of the earth every year is 1 multiplied by 1018kW.h, which is ten thousand times of the total energy consumed in the world year. The utilization of solar energy has been used as an important item for the development of new energy in all countries of the world. However, the solar radiation has a small energy density (about one kilowatt per square meter) and is discontinuous, which brings certain difficulties for large-scale exploitation and utilization. Therefore, in order to widely use solar energy, not only the technical problems should be solved, but also it is necessary to be economically competitive with conventional energy sources.
Aiming at the structure of a heat collector, the prior art has been researched and developed a lot, but the heat collecting capability is not enough on the whole, and the problem that the operation time is long and scaling is easy to happen, so that the heat collecting effect is influenced.
In any form and structure of solar collector, there is an absorption component for absorbing solar radiation, and the structure of the collector plays an important role in absorbing solar energy.
Aiming at the problems, the invention improves on the basis of the previous invention and provides a novel loop heat pipe solar heat collecting system, thereby solving the problems of low heat exchange amount of a heat pipe and uneven heat exchange.
In application, the continuous heat collection and heating of solar energy or no heating at night can cause the stability of internal fluid, namely the fluid does not flow any more or has little mobility, or the flow is stable, so that the vibration performance of the heat collection tube is greatly weakened, and the descaling and heating efficiency of the heat collection tube is influenced. There is therefore a need for improvements to the above-mentioned solar collectors. The applicant has already filed a relevant patent for this application.
However, in practice it has been found that adjusting the vibration of the tube bundle by a fixed periodic variation can result in hysteresis and excessively long or short periods. Therefore, the invention improves the previous application and intelligently controls the vibration, so that the fluid in the fluid can realize frequent vibration, and good descaling and heating effects can be realized.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a heat collecting device with a novel structure. The heat collecting device can collect heat in the daytime, and can perform auxiliary heating and descaling operations at night, so that the heat utilization effect and the descaling effect are improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for descaling a heat collecting device through liquid level difference comprises a heat collecting pipe box, a left upper pipe, a right upper pipe and a heat releasing pipe group, wherein the heat collecting pipe box, the left upper pipe, the right upper pipe and the heat releasing pipe group are positioned at the lower part, the left upper pipe and the right upper pipe are positioned at the upper part of the heat collecting pipe box, the heat releasing pipe group comprises a left heat releasing pipe group and a right heat releasing pipe group, the left heat releasing pipe group is communicated with the left upper pipe and the heat collecting pipe box, the right heat releasing pipe group is communicated with the right upper pipe and the heat collecting pipe box, so that a heating fluid closed cycle is formed by the heat collecting pipe box, the left upper pipe, the right upper pipe and the heat releasing pipe groups, the heat releasing pipe groups are one or more, each heat releasing; the heat collection tube box comprises a first tube opening and a second tube opening, the first tube opening is connected with an inlet of the left heat release tube group, the second tube opening is connected with an inlet of the right heat release tube group, an outlet of the left heat release tube group is connected with the left upper tube, and an outlet of the right heat release tube group is connected with the right upper tube; the descaling method is characterized in that a liquid level detection element is arranged in the heat collection tube box and used for detecting the liquid level of fluid in the lower tube box, and the descaling method comprises the following steps: the electric heater operates at night, the liquid level detection element is in data connection with the controller, the controller extracts liquid level data according to the time sequence and obtains the liquid level difference or the accumulation of the change of the liquid level difference through the comparison of the liquid level data of adjacent time periods, and when the liquid level difference or the change of the liquid level difference is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
Preferably, if the liquid level of the previous period is L1, and the liquid level of the adjacent following period is L2, if L1> L2, the controller controls the electric heater to stop heating when the threshold value is lower; if L1< L2, then below the threshold, the controller controls the electric heater to heat.
The invention has the following advantages:
1. on one hand, the solar heat collecting device is assisted to heat at night, on the other hand, the liquid level difference of the front time and the back time or the accumulated liquid level difference detected by the liquid level sensing element can be judged through the liquid level difference, the evaporation of the internal fluid basically reaches saturation, and the volume of the internal fluid basically does not change greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the liquid level difference rises to a certain degree, the internal fluid starts to enter a stable state again, and at the moment, the fluid needs to be heated so as to be evaporated and expanded again, so that the electric heater needs to be started for heating.
2. The invention increases the heating power of the heat exchange tube periodically and continuously and reduces the heating power, so that the heated fluid can generate the volume which is continuously in a changing state after being heated, and the free end of the heat exchange tube is induced to generate vibration, thereby strengthening heat transfer.
3. The invention provides a heat collecting device with a novel structure, which can improve the heat collecting effect, improve the heat releasing capacity of a heat collecting pipe and reduce the energy consumption.
4. The heat collecting device with new structure has more heat releasing pipe groups in limited space to increase the vibration range of the pipe bundle, strengthen heat transfer and eliminate scale.
5. The heat exchange efficiency can be further improved by the arrangement of the pipe diameters and the interval distribution of the heat release pipe groups in the fluid flowing direction.
6. The invention optimizes the optimal relation of the parameters of the heat collecting device through a large amount of experiments and numerical simulation, thereby realizing the optimal heating efficiency.
Description of the drawings:
FIG. 1 is a front view of a heat collecting device according to the present invention.
FIG. 2 is a front view of the heat collecting system of the present invention.
FIG. 3 is a left side view of the heat collecting device of FIG. 1 according to the present invention.
FIG. 4 is a bottom view of the heat collecting device of FIG. 1 according to the present invention.
FIG. 5 is a schematic view showing the staggered arrangement structure of the heat releasing tube sets of the heat collecting device of the present invention.
FIG. 6 is a schematic diagram of a heat collecting device.
In the figure: 1. the heat radiation pipe group comprises a left heat radiation pipe group 11, a right heat radiation pipe group 12, 21, a left upper pipe, 22, a right upper pipe, 3, a free end, 4, a free end, 5, a free end, 6, a free end, 7, a heat radiation pipe, 8, a heat collection pipe box, 9, an electric heater, 10 a first pipe orifice, 13 a second pipe orifice, a left return pipe 14, a right return pipe 15, a 16 reflector, 17 supporting pieces and a box body 18.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings.
In this document, "/" denotes division and "×", "denotes multiplication, referring to formulas, if not specifically stated.
As shown in fig. 1, a heat collecting device comprises a heat collecting pipe box 8, a left upper pipe 21, a right upper pipe 22 and a heat releasing pipe group 1, wherein the heat releasing pipe group 1 comprises a left heat releasing pipe group 11 and a right heat releasing pipe group 12, the left heat releasing pipe group 11 is communicated with the left upper pipe 21 and the heat collecting pipe box 8, the right heat releasing pipe group 12 is communicated with the right upper pipe 22 and the heat collecting pipe box 8, so that the heat collecting pipe box 8, the left upper pipe 21, the right upper pipe 22 and the heat releasing pipe group 1 form a closed circulation of heating fluid, the heat collecting pipe box 8 is filled with phase change fluid, each heat releasing pipe group 1 comprises a plurality of heat releasing pipes 7 in an arc shape, the end parts of the adjacent heat releasing pipes 7 are communicated, so that the plurality of heat releasing pipes; the heat collecting tube box comprises a first tube opening 10 and a second tube opening 13, the first tube opening 10 is connected with an inlet of a left heat-releasing tube group 11, the second tube opening 13 is connected with an inlet of a right heat-releasing tube group 12, an outlet of the left heat-releasing tube group 11 is connected with a left upper tube 21, and an outlet of the right heat-releasing tube group 12 is connected with a right upper tube 22; the first nozzle 10 and the second nozzle 13 are disposed at one side of the heat collecting tube box 8. Preferably, the left and right heat-releasing tube groups 11 and 12 are symmetrical along the middle of the heat collecting tube box.
Preferably, the upper left tube 21, the upper right tube 22 and the heat-releasing tube group 1 are disposed inside the tank 18, and a fluid, preferably air or water, is disposed in the tank 18 to flow.
Preferably, the left upper tube 21, the right upper tube 22 and the heat collecting tube box 8 extend in a horizontal direction.
Preferably, the fluid flows in a horizontal direction.
Preferably, a plurality of heat radiation tube groups 1 are arranged along the horizontal direction of the left upper tube 21, the right upper tube 22 and the heat collecting tube box 8, and the heat radiation tube groups 1 are connected in parallel.
Preferably, a left return pipe 14 is disposed between the left upper pipe 21 and the heat collecting tube box 8, and a right return pipe 15 is disposed between the right upper pipe 22 and the heat collecting tube box 8. Preferably, the return pipes are provided at both ends of the heat collecting tube box 8.
The heat collecting tube box 8 is filled with phase-change fluid, preferably vapor-liquid phase-change fluid. The fluid heats and evaporates at the heat collecting tube box 8, flows along the heat release tube bundle to the upper left pipe 21 and the upper right pipe 22, and the fluid can produce volume expansion after being heated, thereby forming steam, and the volume of steam is far greater than water, and the steam that consequently forms can carry out the flow of quick impact formula in the coil pipe. Because of volume expansion and steam flow, the free end of the heat-radiating pipe can be induced to vibrate, the vibration is transmitted to the heat-exchanging fluid in the box body 18 by the free end of the heat-exchanging pipe in the vibrating process, and the fluid can be disturbed mutually, so that the peripheral heat-exchanging fluid forms disturbed flow, a boundary layer is damaged, and the purpose of enhancing heat transfer is realized. The fluid is condensed and released heat on the left upper pipe and the right upper pipe and then flows back to the heat collecting pipe box through the return pipe.
According to the invention, the prior art is improved, and the upper pipe and the heat release pipe groups are respectively arranged into two groups distributed on the left side and the right side, so that the heat release pipe groups distributed on the left side and the right side can perform vibration heat exchange descaling, the heat exchange vibration area is enlarged, the vibration is more uniform, the heat exchange effect is more uniform, the heat exchange area is increased, and the heat exchange and descaling effects are enhanced.
The above-mentioned structure has carried out patent application, and this application is to above-mentioned structure further improves, reinforcing scale removal and heat transfer effect.
In the operation of the solar heat collector, although the structure has the elastic vibration descaling effect, the descaling effect needs to be further improved after long-term operation.
It has been found in research and practice that a sustained and stable heat collection results in a fluid-forming stability of the internal heat exchange components, i.e. no fluid flow or little fluid flow, or a steady flow rate, resulting in a greatly reduced vibration performance of the heat-emitting bank 1, which affects the efficiency of descaling and heating of the bank 1. Such as continuous heat collection during the day or continuous non-heat collection during the night, resulting in a reduction in the descaling effect, the following improvements are required for the above-described heat collecting apparatus.
As a modification, an electric heater 9 is provided in the heat collecting tube box 8. The electric heater operates at night, on one hand, the solar heat collecting device is assisted to heat at night, and on the other hand, the heat collecting tube continuously vibrates to remove scale through the operation of the electric heater.
In the prior application of the inventor, a periodic heating mode is provided, and the vibration of the coil is continuously promoted by the periodic heating mode, so that the heating efficiency and the descaling effect are improved. However, adjusting the vibration of the tube bundle with a fixed periodic variation can lead to hysteresis and too long or too short a period. Therefore, the invention improves the previous application and intelligently controls the vibration, so that the fluid in the device can realize frequent vibration, and a good descaling effect is realized.
Aiming at the defects in the technology researched in the prior art, the invention provides a novel electric heating descaling heat collector capable of intelligently controlling vibration. This heat collector can realize fine scale removal effect.
Self-regulation vibration based on pressure
Preferably, a pressure detection element is arranged in the heat exchange component and used for detecting the pressure in the heat exchange component, the controller extracts pressure data according to a time sequence, the pressure data in adjacent time periods are compared to obtain the pressure difference or the accumulation of the pressure difference change, and when the pressure difference or the accumulation of the pressure difference change is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
Through the pressure difference of the previous and subsequent time periods or the accumulated pressure difference detected by the pressure sensing element, the evaporation of the fluid inside can be judged to be basically saturated through the pressure difference, and the volume of the fluid inside is basically not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the pressure difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and at the moment, the fluid needs to be heated so as to be evaporated and expanded again, so that the electric heater needs to be started for heating.
The stable state of the fluid is judged according to the pressure difference or the accumulation of the pressure difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the running time problem is solved.
Preferably, if the pressure of the preceding period is P1 and the pressure of the adjacent following period is P2, if P1< P2, the controller controls the electric heater to stop heating when being lower than the threshold value; if P1> P2, the controller controls the electric heater to heat when the threshold value is lower.
The current electric heater is determined to be in a heating state or a non-heating state through sequential pressure size judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if the pressure of the preceding period is P1, the pressure of the adjacent succeeding period is P2, and if P1 is P2, heating is judged according to the following:
if P1 is greater than the pressure of the first data, the controller controls the electric heater to stop heating; wherein the first data is greater than the pressure of the phase change fluid after the phase change; preferably the first data is a pressure at which the phase change fluid is substantially phase-changed;
if P1 is less than or equal to the pressure of the second data, the controller controls the electric heater to continue heating, wherein the second data is less than or equal to the pressure at which the phase change fluid does not change phase.
The first data is pressure data in a fully heated state, and the second data is pressure data in the absence of heating or in the beginning of heating. The judgment of the pressure is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the pressure sensing element is disposed within the heat collecting channel 8.
Preferably, the pressure sensing element is disposed at the free end. Through setting up at the free end, can perceive the pressure variation of free end to realize better control and regulation.
Preferably, the pressure sensing element is arranged in the upper left tube 21 and/or the upper right tube 22.
Preferably, the pressure sensing elements are disposed within the upper left tube 21 and the upper right tube 22. The average of the pressures of the two headers can be selected as regulating data.
Preferably, the number of the pressure sensing elements is n, and the pressure P in the current time period is calculated in sequenceiPressure Q of the preceding periodi-1Difference D ofi＝Pi-Qi-1And for n pressure differences DiPerforming arithmetic cumulative summation
Figure BDA0002228562470000071
When the value of Y is lower than a set threshold value, the controller controls the electric heater to stop heating or continue heating.
Preferably, when Y is greater than 0 and is lower than the threshold value, the controller controls the electric heater to stop heating; if Y <0, then lower than the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through sequential pressure size judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if Y is 0, heating is judged according to the following:
if P isiThe arithmetic mean of the first data is greater than the pressure of the first data, the controller controls the electric heater to stop heating; wherein the first data is greater than the pressure of the phase change fluid after the phase change; preferably the pressure at which the phase change fluid substantially changes phase;
if P isiIs less than the pressure of the second data, wherein the second data is less than or equal to the pressure at which the phase change fluid does not undergo the phase change.
The first data is pressure data in a fully heated state, and the second data is pressure data in the absence of heating or in the beginning of heating. The judgment of the pressure is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the period of time for measuring the pressure is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.
Preferably, the threshold is 100-1000 pa, preferably 500 pa.
Preferably, the pressure value may be an average pressure value over a period of the time period. Or may be a pressure at a certain time within a time period. For example, preferably both are pressures at the end of the time period.
Preferably, the pressure detecting element is provided at the free end. Through setting up at the free end, can perceive the pressure variation of free end to realize better control and regulation.
Independently adjusting vibration based on temperature
Preferably, the heat exchange component is internally provided with a temperature detection element for detecting the temperature inside the heat exchange component, the controller extracts temperature data according to a time sequence, the temperature difference or the accumulation of the temperature difference change is obtained through the comparison of the temperature data of adjacent time periods, and when the temperature difference or the accumulation of the temperature difference change is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
The temperature difference or the accumulated temperature difference of the previous time period and the later time period detected by the temperature sensing element can be used for judging that the evaporation of the fluid inside is basically saturated and the volume of the fluid inside is not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the temperature difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and the fluid needs to be heated to evaporate and expand again, so that the electric heater needs to be started for heating.
The stable state of the fluid is judged according to the temperature difference or the accumulation of the temperature difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the problem of operation time is solved.
Preferably, if the temperature of the preceding period is P1 and the temperature of the adjacent succeeding period is P2, if P1< P2, the controller controls the electric heater to stop heating when being below the threshold; if P1> P2, the controller controls the electric heater to heat when the threshold value is lower.
The current electric heater is determined to be in a heating state or a non-heating state through sequential temperature size judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if the temperature of the preceding period is P1, the temperature of the adjacent succeeding period is P2, and if P1 is P2, heating is judged according to the following:
if P1 is greater than the temperature of the first data, the controller controls the electric heater to stop heating; wherein the first data is greater than the temperature of the phase change fluid after the phase change; preferably the first data is a temperature at which the phase change fluid substantially changes phase;
if P1 is less than or equal to the temperature of the second data, the controller controls the electric heater to continue heating, wherein the second data is less than or equal to the temperature at which the phase change fluid does not change phase.
The first data is temperature data of a sufficiently heated state, and the second data is temperature data of no heating or temperature data of the beginning of heating. The judgment of the temperature is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the temperature sensing element is disposed within the heat collecting channel 8.
Preferably, the temperature sensing element is disposed at the free end. Through setting up at the free end, can perceive the temperature variation of free end to realize better control and regulation.
Preferably, the temperature sensing element is arranged in the upper left tube 21 and/or the upper right tube 22.
Preferably, the temperature sensing elements are disposed within the upper left and right tubes 21, 22. The average of the temperatures of the two headers can be selected as the regulating data.
Preferably, the number of the temperature sensing elements is n, and the current time period temperature Pi and the previous time period temperature Q are calculated in sequencei-1Difference D ofi＝Pi-Qi-lAnd for n temperature differences DiPerforming arithmetic cumulative summation
Figure BDA0002228562470000101
When the value of Y is lower than a set threshold value, the controller controls the electric heater to stop heating or continue heating.
Preferably, when Y is greater than 0 and is lower than the threshold value, the controller controls the electric heater to stop heating; if Y <0, then lower than the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through sequential temperature size judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if Y is 0, heating is judged according to the following:
if P isiIs greater than the temperature of the first data, the controller controls the electric heater to stop heating; wherein the first data is greater than the temperature of the phase change fluid after the phase change; preferably the temperature at which the phase change fluid substantially changes phase;
if P isiIs less than the temperature of the second data, wherein the second data is less than or equal to the temperature at which the phase change of the phase change fluid does not occur.
The first data is temperature data of a sufficiently heated state, and the second data is temperature data of no heating or temperature data of the beginning of heating. The judgment of the temperature is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the period of time for measuring the temperature is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.
Preferably, the temperature value may be an average temperature value over a period of the time period. Or may be the temperature at a certain point in time. For example, preferably both are temperatures at the end of the time period.
Preferably, the temperature detection element is provided at the free end. Through setting up at the free end, can perceive the temperature variation of free end to realize better control and regulation.
Preferably, the temperature sensing element is provided at an upper end in the lower and/or upper header.
Preferably, the temperature detection element is provided at an upper end in the lower and upper headers.
Preferably, the temperature detection element is provided at the free end. Through setting up at the free end, can perceive the temperature variation of free end to realize better control and regulation.
Thirdly, automatically adjusting vibration based on liquid level
Preferably, a liquid level detection element is arranged in the heat collection tube box and used for detecting the liquid level of the fluid in the lower tube box, the liquid level detection element is in data connection with the controller, the controller obtains the liquid level difference or the accumulation of the change of the liquid level difference according to the liquid level data extracted by the time sequence and through the comparison of the liquid level data in adjacent time periods, and when the liquid level difference or the change of the liquid level difference is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
Through the liquid level difference of the front time and the back time or the accumulated liquid level difference detected by the liquid level sensing element, the evaporation of the internal fluid can be judged to be basically saturated through the liquid level difference, and the volume of the internal fluid is basically not changed greatly. So that the fluid undergoes volume reduction to thereby realize vibration. When the liquid level difference rises to a certain degree, the internal fluid starts to enter a stable state again, and at the moment, the fluid needs to be heated so as to be evaporated and expanded again, so that the electric heater needs to be started for heating.
The stable state of the fluid is judged according to the liquid level difference or the accumulation of the change of the liquid level difference, so that the result is more accurate, and the problem of error increase caused by aging due to the problem of operation time is solved.
Preferably, if the liquid level of the previous period is L1, and the liquid level of the adjacent following period is L2, if L1> L2, the controller controls the electric heater to stop heating when the threshold value is lower; if L1< L2, then below the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through the sequential liquid level judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if the liquid level of the preceding period is L1, the liquid level of the adjacent succeeding period is L2, and if L1 is L2, heating is judged according to the following:
if L1 is less than the liquid level of the first data or L1 is 0, the controller controls the electric heater to stop heating; wherein the first data is greater than the liquid level of the phase-change fluid after the phase change; preferably the first data is a level at which the phase change fluid is substantially phase changed;
the controller controls the electric heater to continue heating if L1 is greater than or equal to a level of a second datum at which the phase change fluid does not undergo a phase change.
The first data is liquid level data of a fully heated state, including liquid level of dry-out, and the second data is liquid level data of no heating or heating beginning. Through the judgment of the liquid level, whether the current electric heater is in a heating state or a non-heating state is also determined, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the number of the liquid level sensing elements is n, and the liquid level L in the current time period is calculated in sequenceiAnd the liquid level Q of the previous time periodi-1Difference D ofi＝Li-Qi-1And for n liquid level differences DiPerforming arithmetic cumulative summation
Figure BDA0002228562470000121
When the value of Y is lower than a set threshold value, the controller controls the electric heater to stop heating or continue heating.
Preferably, when Y is greater than 0 and is lower than the threshold value, the controller controls the electric heater to stop heating; if Y <0, then lower than the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through the sequential liquid level judgment, so that the running state of the electric heater is determined according to different conditions.
Preferably, if Y is 0, heating is judged according to the following:
if L isiIs less than the liquid level of the first data or is 0, the controller controls the electric heater to stop heating; wherein the first data is greater than the liquid level of the phase-change fluid after the phase change; preferably a level at which the phase change fluid is substantially phase-changed;
if L isiIs greater than the level of the second data, wherein the second data is less than or equal to the level at which the phase change fluid does not undergo a phase change.
The first data is liquid level data of a fully heated state, including liquid level of dry-out, and the second data is liquid level data of no heating or heating beginning. Through the judgment of the liquid level, whether the current electric heater is in a heating state or a non-heating state is also determined, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the period of time for which the measurement is also made is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.
Preferably, the threshold is 1-10 mm, preferably 4 mm.
Preferably, the water level value may be an average water level value over a period of the time period. Or may be a water level value at a certain time within the time period. Such as preferably both water levels at the end of the time period.
Fourthly, automatically adjusting vibration based on speed
Preferably, a speed detection element is arranged in the free end of the tube bundle and used for detecting the flow speed of fluid in the free end of the tube bundle, the speed detection element is in data connection with the controller, the controller extracts speed data according to a time sequence, the speed difference or the accumulation of the speed difference change is obtained through comparison of the speed data of adjacent time periods, and when the speed difference or the accumulation of the speed difference is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
The difference in time velocity or the cumulative velocity difference before and after detection by the velocity sensing element can be used to determine that the evaporation of the fluid inside has substantially reached saturation and that the volume of the fluid inside has not substantially changed, in which case the fluid inside is relatively stable and the tube bundle is less vibratile, and therefore needs to be adjusted to vibrate and stop heating. So that the fluid undergoes volume reduction to thereby realize vibration. When the speed difference is reduced to a certain degree, the internal fluid starts to enter a stable state again, and the fluid needs to be heated to evaporate and expand again, so that the electric heater needs to be started for heating.
The stable state of the fluid is judged according to the speed difference or the accumulation of the speed difference change, so that the result is more accurate, and the problem of error increase caused by aging due to the running time problem is solved.
Preferably, if the speed of the previous period is V1 and the speed of the adjacent following period is V2, the controller controls the electric heater to stop heating if V1< V2, below the threshold; if V1> V2, then below the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through the judgment of the speed, so that the running state of the electric heater is determined according to different conditions.
Preferably, if the speed of the preceding time period is V1, the speed of the adjacent succeeding time period is V2, and if V1 is equal to V2, heating is judged according to the following:
if the V1 is greater than the speed of the first data, the controller controls the electric heater to stop heating when the V1 is lower than the threshold value; wherein the first data is greater than the speed of the phase change fluid after the phase change; preferably the first data is the speed at which the phase change fluid is substantially phase changed;
below the threshold, the controller controls the electric heater to continue heating if V1 is less than or equal to the velocity of the second data, which is less than or equal to the velocity at which no phase change of the phase-change fluid occurs.
The first data is speed data of a sufficiently heated state, and the second data is speed data of no heating or heating just started. The judgment of the speed is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the number of the speed sensing elements is n, and the speed V of the current time period is calculated in sequenceiAnd the previous time speed Qi-1Difference D ofi＝Vi-Qi-1And for n speed differences DiPerforming arithmetic cumulative summation
Figure BDA0002228562470000141
When the value of Y is lower than a set threshold value, the controller controls the electric heater to stop heating or continue heating.
Preferably, when Y is greater than 0 and is lower than the threshold value, the controller controls the electric heater to stop heating; if Y <0, then lower than the threshold, the controller controls the electric heater to heat.
The current electric heater is determined to be in a heating state or a non-heating state through the judgment of the speed, so that the running state of the electric heater is determined according to different conditions.
Preferably, if Y is 0, heating is judged according to the following:
if ViIs greater than the speed of the first data, the controller controls the electric heater to stop heating; wherein the first data is greater than the speed of the phase change fluid after the phase change; preferably the rate at which the phase change fluid changes phase substantially;
if ViIs less than a second data rate, wherein the second data rate is less than or equal to a rate at which no phase change of the phase change fluid occurs.
The first data is speed data of a sufficiently heated state, and the second data is speed data of no heating or heating just started. The judgment of the speed is also used for determining whether the current electric heater is in a heating state or a non-heating state, so that the operation state of the electric heater is determined according to different conditions.
Preferably, the period of time for measuring the speed is 1 to 10 minutes, preferably 3 to 6 minutes, and further preferably 4 minutes.
Preferably, the threshold is 1-3 m/s, preferably 2 m/s.
Preferably, the speed value may be an average speed value within a period of the time period. Or may be a speed at a certain time within the time period. For example, preferably both are speeds at the end of the time period.
Preferably, the heat release pipes of the left heat release pipe group are distributed around the axis of the left upper pipe, and the heat release pipes of the right heat release pipe group are distributed around the axis of the right upper pipe. The left upper pipe and the right upper pipe are arranged as circle centers, so that the distribution of the heat release pipes can be better ensured, and the vibration and the heating are uniform.
Preferably, the left heat-releasing tube group and the right heat-releasing tube group are both plural.
Preferably, the left heat-releasing tube group and the right heat-releasing tube group are mirror-symmetrical along a plane on which a vertical axis of the heat collecting tube box is located. Through such setting, can make the heat release pipe distribution of heat transfer more reasonable even, improve the heat transfer effect.
Preferably, the heat collecting tube box 8 has a flat tube structure. The heat absorption area is increased by arranging the flat tube structure. So that the heat collecting tube box 8 can be ensured to be positioned at the focal position of the reflector even if the installation position deviates a little.
Preferably, the left heat-releasing tube group 11 and the right heat-releasing tube group 12 are arranged in a staggered manner in the horizontal extending direction, as shown in fig. 5. Through the staggered distribution, can make to vibrate on different length and release heat and scale removal for the vibration is more even, strengthens heat transfer and scale removal effect.
Preferably, a reflecting mirror 16 is provided at a lower portion of the heat collecting device, the heat collecting tube box is located at a focal position of the reflecting mirror 16, and the left and right heat releasing tube groups are located in the fluid passage. Thereby forming a solar energy collection system.
Preferably, a support 17 is included, and the support 17 supports the heat collecting device.
Preferably, a fluid channel is included within which fluid flows. As shown in fig. 2, the heat collecting tube box 8 is located at a lower end of the fluid passage, as shown in fig. 2. The upper left tube 21, the upper right tube 22, the left heat-releasing tube group 11, and the right heat-releasing tube group 12 are provided in the fluid passage, and heat the fluid in the fluid passage by releasing heat.
Preferably, the flow direction of the fluid is the same as the direction in which the left and right upper tubes 21 and 22 and the heat collecting tube box 8 extend. Through such arrangement, the fluid scours the heat release pipe set when flowing, especially the free end of the heat release pipe set, so that the free end vibrates, heat transfer is enhanced, and the descaling effect is achieved.
Preferably, the heat release tube group 1 is provided in plural (for example, on the same side (left side or right side)) along the flow direction of the fluid in the fluid passage, and the tube diameter of the heat release tube group 1 (for example, on the same side (left side or right side)) along the flow direction of the fluid in the fluid passage becomes larger.
Along the flowing direction of the fluid, the temperature of the fluid is continuously increased, so that the heat exchange temperature difference is continuously reduced, and the heat exchange capacity is increased more and more. Through the pipe diameter grow of heat release nest of tubes, can guarantee that more steam passes through upper portion and gets into heat release nest of tubes, guarantee along fluid flow direction because the steam volume is big and the vibration is effectual to make whole heat transfer even. The distribution of steam in all heat release pipe groups is even, further strengthens heat transfer effect for the whole vibration effect is even, and the heat transfer effect increases, further improves heat transfer effect and scale removal effect.
Preferably, the heat release pipe diameter of the heat release pipe group (for example, the same side (left side or right side)) is increased along the flowing direction of the fluid in the fluid passage.
Through so setting up, avoid the fluid all to carry out the heat transfer at front, and the heat transfer of messenger increases to the rear portion as far as possible to form the heat transfer effect of similar countercurrent. Experiments show that better heat exchange effect and descaling effect can be achieved by adopting the structural design.
Preferably, the heat release pipe groups on the same side (left side or right side) are arranged in plurality along the flowing direction of the fluid in the fluid channel, and the interval between the adjacent heat release pipe groups on the same side (left side or right side) is gradually reduced from the top to the bottom. The specific effect is similar to the effect of the previous pipe diameter change.
Preferably, the spacing between the heat release pipe groups on the same side (left side or right side) along the flowing direction of the fluid in the fluid channel is increased in a decreasing amplitude. The specific effect is similar to the effect of the previous pipe diameter change.
In tests, it was found that the tube diameters and distances of the upper left tube 21 and the upper right tube 22 and the tube diameters of the heat release tubes can have an influence on the heat exchange efficiency and uniformity. If the distance between the collector is too big, then heat exchange efficiency is too poor, and the distance between the heat release pipe is too little, then heat release pipe distributes too closely, also can influence heat exchange efficiency, and the pipe diameter size of collector and heat exchange tube influences the volume of the liquid or the steam that holds, then can exert an influence to the vibration of free end to influence the heat transfer. Therefore, the tube diameters and distances of the upper left tube 21 and the upper right tube 22 and the tube diameters of the heat release tubes have a certain relationship.
The invention provides an optimal size relation summarized by numerical simulation and test data of a plurality of heat pipes with different sizes. Starting from the maximum heat exchange amount in the heat exchange effect, nearly 200 forms are calculated. The dimensional relationship is as follows:
the distance between the center of the upper left tube 21 and the center of the upper right tube 21 is M, the tube diameter of the upper left tube 21 and the radius of the upper right tube 22 are the same, B is B, the radius of the axis of the innermost heat radiation tube in the heat radiation tube is N1, and the radius of the axis of the outermost heat radiation tube is W2, so that the following requirements are met:
N1/W2 ═ a × Ln (B/M) + B; wherein a, b are parameters and Ln is a logarithmic function, wherein 0.5788< a <0.6002, 1.6619< b < 1.6623; preferably, a is 0.5790 and b is 1.6621.
Preferably, 35< B <61 mm; 230< M <385 mm; 69< N1<121mm, 119< W2<201 mm.
Preferably, the number of the heat release pipes of the heat release pipe group is 3 to 5, preferably 3 or 4.
Preferably, 0.55< N1/W2< 0.62; 0.154< B/M < 0.166.
Preferably, 0.57< N1/W2< 0.61; 0.158< B/M < 0.162.
Preferably, an included angle A formed between the midpoint of the bottom of the heat collection box and the circle centers of the upper left tube 21 and the upper right tube 22 is 40-100 degrees (angle), and preferably 60 degrees (angle).
Preferably, the radius of the heat-radiating pipe is preferably 10-40 mm; preferably 15 to 35mm, more preferably 20 to 30 mm.
Preferably, the arc between the ends of the free ends 3, 4, centered on the central axis of the left header, is 95-130 degrees, preferably 120 degrees. The same applies to the curvature of the free ends 5, 6 and the free ends 3, 4. Through the design of the preferable included angle, the vibration of the free end is optimal, and therefore the heating efficiency is optimal.
Preferably, the tube bundle of the heat-releasing tube group 1 is an elastic tube bundle.
The heat exchange coefficient can be further improved by arranging the tube bundle of the heat release tube group 1 with an elastic tube bundle.
The number of the heat release pipe groups 1 is plural, and the plurality of the heat release pipe groups 1 are in a parallel structure.
Although the present invention has been described with reference to the preferred embodiments, it is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (3)

1. A method for descaling a heat collecting device through liquid level difference comprises a heat collecting pipe box, a left upper pipe, a right upper pipe and a heat releasing pipe group, wherein the heat collecting pipe box, the left upper pipe, the right upper pipe and the heat releasing pipe group are positioned at the lower part, the left upper pipe and the right upper pipe are positioned at the upper part of the heat collecting pipe box, the heat releasing pipe group comprises a left heat releasing pipe group and a right heat releasing pipe group, the left heat releasing pipe group is communicated with the left upper pipe and the heat collecting pipe box, the right heat releasing pipe group is communicated with the right upper pipe and the heat collecting pipe box, so that a heating fluid closed cycle is formed by the heat collecting pipe box, the left upper pipe, the right upper pipe and the heat releasing pipe groups, the heat releasing pipe groups are one or more, each heat releasing; the heat collection tube box comprises a first tube opening and a second tube opening, the first tube opening is connected with an inlet of the left heat release tube group, the second tube opening is connected with an inlet of the right heat release tube group, an outlet of the left heat release tube group is connected with the left upper tube, and an outlet of the right heat release tube group is connected with the right upper tube; the descaling method is characterized in that an electric heater is arranged in a heat collecting tube box, a liquid level detection element is arranged in the heat collecting tube box and used for detecting the liquid level of fluid in a lower tube box, and the descaling method comprises the following steps: the electric heater operates at night, the liquid level detection element is in data connection with the controller, the controller extracts liquid level data according to the time sequence and obtains the liquid level difference or the accumulation of the change of the liquid level difference through the comparison of the liquid level data of adjacent time periods, and when the liquid level difference or the change of the liquid level difference is lower than a threshold value, the controller controls the electric heater to stop heating or continue heating.
2. The method of claim 1, wherein if the liquid level of the previous period is L1 and the liquid level of the adjacent following period is L2, the controller controls the electric heater to stop heating if L1> L2 is below the threshold; if L1< L2, then below the threshold, the controller controls the electric heater to heat.
3. The utility model provides a heat transfer device, heat transfer device is including the thermal-arrest pipe case, upper left pipe, upper right pipe and the heat release nest of tubes that are located the lower part, and upper left pipe, upper right pipe are located the upper portion of thermal-arrest pipe case.
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JP2006029672A (en) * 2004-07-15 2006-02-02 Japan Aerospace Exploration Agency Heat transportation device using latent heat fluid loop
CN201344649Y (en) * 2009-01-24 2009-11-11 张斌 Novel double-loop circulation solar water heater
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