JP2013228184A - Linear solar concentrator and solar concentration power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear solar concentrator that can reduce variations of light concentration/heat collection energy, reduce loss of light, and improve heating efficiencies against the changes of daily sun elevation.SOLUTION: Multiple reflection lines L1-L8 are disposed in the north-south direction, and one light receiving line G is disposed in the east-west direction. Mirror segments 1a, 1b, 1c, ... are provided on each reflection line. Light concentration ratio in an irradiation area is doubled by collecting the reflection light from two each reflection lines adjacent to the east-west direction into one irradiation area of a receivers 2.

Description

  The present invention relates to a linear solar light collecting device formed by arranging a plurality of sunlight reflection lines in parallel, and a solar light collecting power generation system.

  A so-called linear Fresnel solar concentrator is known as a conventional linear solar concentrator formed by arranging a plurality of sunlight reflection lines in parallel.

  FIG. 23 shows an example of a conventional linear Fresnel solar concentrator as a first example (see Non-Patent Document 1 and Patent Document 1). Here, FIG. 23A is a perspective view, and FIG. 23B is a view seen from one end side of the light receiving line.

  As shown in the figure, the linear Fresnel solar concentrator of the first example has a plurality of reflection lines L1, L2,... Set in parallel on the ground and arranged in a row of reflection lines L1, L2,. The light receiving lines G1, G2,... Are set in a direction parallel to the direction of the reflection lines at a constant cycle. Each of the reflection lines L1, L2,... Is arranged with a number of rectangular mirror plates H, H,... As a heliostat, and each light receiving line G1, G2,. Heaters R, R,... Are installed in parallel at regular intervals.

  The mirror plates H, H,... In each row are individually controlled in rotation angle around the central rotation axis set in each reflection line L1, L2,. .. Reflects the sunlight incident on the mirror surface and causes the nearby receiver R to receive the reflected light. And the heat | fever of the reflected light received by the receiver R is converted into high temperature water vapor | steam via a heat medium. Each of the reflection lines L1, L2,... And the receiver R are arranged in parallel in the north-south direction (SN), and the mirror plates H on the reflection lines L1, L2,. H,... Track the movement of the sun, and rotate and adjust the angle of each reflection line in the east-west direction (EW) so that the reflected light is always collected near the receiver R.

  A solar concentrator is used in a concentrating solar power generation system, and as a commercial plant for a concentrating solar power generation system, a gutter-shaped parabolic mirror is used, and a solar pipe is installed on a pipe installed at the focal point of the mirror. It is installed in the center using a parabolic trough solar power generation system that concentrates light and heats fluid (oil etc.) flowing through the pipe and generates electricity using the heat energy, and a plane mirror with a solar tracking device. A central tower solar power generation system has already been in operation as a commercial plant that collects sunlight by concentrating sunlight on a heat collector in a tower and collects the heat from the fluid flowing in the upper part of the tower to generate electricity. ing.

  Trough solar power generation system is relatively low cost, but it is difficult to increase efficiency because the temperature of the heated fluid is low, and tower type solar power generation system can obtain high temperature fluid, but it is highly accurate. There is a disadvantage of high cost due to the necessity of condensing light.

  In contrast, linear Fresnel solar concentrators are less susceptible to wind than trough and tower solar concentrators, have a relatively low rigidity and simple structure, and land use efficiency Therefore, it is one of the concentrated solar thermal power generation systems that is attracting the most attention as a commercial plant in that low power generation costs can be realized.

  As described above, the linear Fresnel type solar concentrator has a simple structure compared to trough type and tower type power generators, and can realize low power generation costs. There is a problem that light loss is large and it is difficult to obtain high light collection and heat collection efficiency.

  The loss of sunlight is caused by the incident light beam being kicked on the mirror plate (called cosine loss), the light beam reflected by the mirror plate being blocked by another mirror plate (called blocking), and the light beam entering the mirror plate. Is caused by being blocked by another mirror plate (called shadowing).

  FIG. 24 shows an image of cosine loss and blocking among the optical losses. Shadowing is not shown in FIG. 24 because it occurs particularly when the solar incident light on the mirror is obliquely incident.

  Such light loss is caused when the inclination of the mirror plate H is large with respect to the ground surface, or when the angle of the mirror plate H is adjusted to follow the solar altitude, the change in the rotation angle of the mirror plate H increases. Such optical loss tends to increase. In FIG. 24, for example, when the receiver R of the conventional linear Fresnel solar concentrator is installed in the north-south direction, by tilting the mirror plates H, H,. Apparently, the reflected light from the mirror plates H, H,... Therefore, the mirror plate on the reflection line farther from the receiver R has a larger inclination with respect to the ground surface, and cosine loss and light loss due to blocking increase.

  Moreover, in order to follow the sun's trajectory from morning to evening, the adjustment angle of the mirror plate H changes by about ± 45 degrees or more in the east-west direction, so cosine loss and light loss due to blocking, especially when the solar altitude is low in the morning and evening. Increases, and the amount of fluctuation in the concentration and heat collection energy per day increases. Therefore, the upper limit of the temperature obtained is limited to 400 ° C. to 500 ° C. with water vapor, and a high temperature of 600 ° C. or higher cannot be obtained.

  Also, even if a large number of mirror plates are arranged on the reflection line in the east-west direction and the mirror installation area is increased, the above-mentioned light loss becomes larger and the high light collection efficiency is obtained with the mirror plate far from the receiver. I can't. Furthermore, since the number of mirror plates that can be reflected by a single receiver is limited by itself, when a large number of mirror plates are arranged over a wide range, one light is received for each set of mirror plates. It is necessary to set a line and install a receiver R for each light receiving line, and collect and extract the heat of reflected light received for each receiver R. For these reasons, the temperature obtained from the conventional linear Fresnel solar concentrator is limited to about 500 ° C.

  As a device for reducing such light loss, Patent Document 2 discloses a linear Fresnel type solar light collecting device in which the longitudinal direction of each reflection line and the longitudinal direction of the receiver are both arranged in parallel in the east-west direction. This apparatus will be described as the preceding example 2. As shown in FIG. 25, the apparatus of the prior example 2 rotates each mirror plate H, H,... On each reflection line L1 (L2, L3...) In the east-west direction with respect to the sun trajectory. Instead, the reflected light is guided to the receiver R by rotating only in the north-south direction.

  According to this apparatus, since the mirror rotation angle in the north-south direction is as small as several degrees on one day (morning and evening) and about ± 15 ° even in a year, the aforementioned optical loss can be greatly reduced. Therefore, if a large number of mirror plates are arranged in the north-south direction and the installation area of the mirror plates is increased, the total amount of collected heat energy received by the receiver R can be increased.

  However, since the mirror angle in the east-west direction cannot be adjusted in the device of the preceding example 2, the linear condensing region condensed by the mirror plate H is greatly deviated from the receiver especially when the solar altitude is low in the morning and evening. Therefore, there is a problem that the fluctuation of the heat collection energy per day is large.

  Moreover, since the reflection line and the receiver are arranged in parallel in any of the devices of the first and second examples, the light beam condensed on the receiver becomes a substantially uniform irradiation region on the line. In such an irradiation region, there is a problem that when the temperature rises to near 600 ° C., re-radiation increases, and the efficiency of the amount of heat absorbed by the heat medium is likely to decrease.

  That is, in the apparatus of the first example, since the optical loss such as cosine loss, blocking, shadowing, etc. on the mirror plate is large, the heat generation temperature remains at 500 ° C. and the fluctuation of the heat collection energy per day is large, and Even if a large number of mirror plates are arranged over a wide range, the light loss increases as the distance from the receiver increases, and there is a problem that the light collection efficiency is limited. Further, in any of the devices of the preceding examples 1 and 2, the problem is that the heat radiation is increased when the temperature of the irradiation region on the receiver rises to a high temperature near 600 ° C., and the efficiency of the amount of heat absorbed by the heat medium is likely to decrease. There is.

  The present invention has been made to solve such a problem, and in a linear solar light collecting device, reduction in light collection and heat collection energy fluctuations with respect to changes in solar altitude of the day, reduction in light loss, And to improve the heating efficiency.

  The present invention is a linear solar light collecting device having a plurality of reflection lines and one light receiving line, wherein the reflection lines are set in parallel in the north-south direction, and the light receiving line is located above the reflection line. A heliostat composed of a plurality of mirror segments is installed in each reflection line, and the light receiving line receives reflected light of sunlight irradiated from the heliostat and collects heat. One receiver is provided, and includes angle adjusting means capable of individually adjusting the angles of the mirror segments, and the angle adjusting means receives light reflected on the receiver from a plurality of reflection lines adjacent in the east-west direction. It is a linear sunlight condensing device that makes it possible to adjust the concentration ratio in the light receiving region by combining the regions.

  ADVANTAGE OF THE INVENTION According to this invention, in a linear sunlight condensing device, reduction of condensing and heat collection energy fluctuation | variation with respect to the change of the solar height of the day, reduction of light loss, and improvement of a heating efficiency are realizable.

It is a figure which shows the basic composition of the linear sunlight condensing device which concerns on embodiment of this invention. It is a figure which shows schematic structure of the mirror segment in FIG. It is a figure which shows the point which adjusts the rotation angle of the mirror segment in FIG. 1 to the north-south direction and the east-west direction. It is sectional drawing which shows the structure of the receiver in FIG. It is a figure for demonstrating the irradiation area | region on the light reception line in FIG. It is a figure which shows the example of arrangement | positioning of the mirror segment in FIG. It is a figure which shows an example of the structural model of the linear sunlight condensing apparatus shown in FIG. It is a top view of another example of the structural model of the linear sunlight condensing apparatus shown in FIG. It is a figure which shows the structural model of the prior example 1. FIG. It is a figure which shows the structural model of the prior example 2. FIG. It is a figure which shows the condensing simulation result of the structural model of the linear sunlight condensing device shown in FIG. 7 thru | or FIG. It is a figure which shows one example of the sunlight condensing electric power generation system using the linear sunlight condensing apparatus shown in FIG. It is a figure which shows the structural model of the linear sunlight condensing apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing device which concerns on the 3rd Embodiment of this invention. It is a side view of the structural model of the linear sunlight condensing device which concerns on the 4th Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing device which concerns on the 5th Embodiment of this invention. It is a figure for demonstrating the principal part structure of the receiver in FIG. It is a front view of the structural model of the linear sunlight condensing device which concerns on the 6th Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing device which concerns on the 7th Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing device which concerns on the 8th Embodiment of this invention. It is a figure which shows the structural model of the linear sunlight condensing device which concerns on the 9th Embodiment of this invention. It is a figure which shows one example (previous example 1) of the conventional linear Fresnel type sunlight condensing device. It is a figure for demonstrating cosine loss and blocking. It is a figure which shows the other example (prior example 2) of the conventional linear Fresnel type sunlight condensing apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration of linear solar concentrator]
Before describing the embodiment of the present invention, the configuration of the linear solar light collecting apparatus, which is the basic configuration of the embodiment of the present invention, will be described.

<Example of arrangement of heliostat and receiver>
FIG. 1 is a diagram illustrating an arrangement example of a heliostat and a receiver as a basic configuration of a linear solar light collecting apparatus according to an embodiment of the present invention.

  As shown in the figure, this linear solar light collecting device is a linear Fresnel type solar light collecting device having a set of a plurality of reflection lines L1, L2,. The plurality of reflection lines L1, L2,... Are set in parallel to the heat receiving zone Z set in the north-south direction on the ground, and the heliostat 1 is installed in each reflection line. In this linear solar light collecting apparatus, an example is shown in which the reflection lines are set in eight rows consisting of L1 to L8, but the number of reflection lines is not limited to eight, and can be set to an arbitrary number.

  The heliostat 1 installed on each line of the reflection lines L1, L2,... Is incident on each part of the reflection lines L1, L2,. Are reflected toward the light receiving line G.

  On the other hand, the light receiving line G is set in the east-west direction, that is, in a direction orthogonal to each of the reflective lines L1, L2,. In G, one receiver 2 is installed. The receiver 2 receives the reflected light of sunlight irradiated from the heliostat 1 in each row and collects heat. When the size of the heliostat is 1 m × 2 m, the installation height of the receiver 2 is approximately 20 m.

  Here, the setting direction of the plurality of reflection lines L1, L2,... Is not limited to the case where the reflection lines L1, L2,. As long as the reflected light of sunlight entering the heliostat 1 can be effectively received by the receiver 2 installed in the light receiving line G, a slight deviation from the north-south direction is allowed as an error range. The same applies to the light receiving line G. That is, as long as the reflected light of sunlight from the heliostat 1 can be effectively received by the receiver 2, an error range is allowed even if the arrangement direction of the light receiving lines G is slightly deviated from the east-west direction.

<Schematic configuration of mirror segments arranged in the light receiving line>
FIG. 2 is a diagram showing a schematic configuration of mirror segments arranged in the light receiving line in FIG. Here, the configuration of the heliostat 1 installed on the reflection line L1 is shown on behalf of the reflection lines in each row.

  As shown in FIG. 2, a plurality of mirror segments 1a, 1b, 1c,... Are arranged in a row direction (north-south direction) over a certain range on the ground as a heliostat 1 on the reflection line L1. . Similarly, a plurality of mirror segments 1a, 1b, 1c,... Are arranged in the row direction on the reflection lines L2, L3,... In each column, and as a result, the heat receiving zone Z is aligned in the row direction. The mirror segments 1a, 1b, 1c,.

<Rotation angle adjustment of mirror segment>
FIG. 3 is a diagram showing a procedure for adjusting the rotation angle of each mirror segment arranged in the reflection line in the north-south direction and the east-west direction.

  As shown in FIG. 3, the mirror segments 1 a, 1 b, 1 c,... In the same row are attached in common to the main rotation axis X along the north-south direction. The rotation of the mirror segments 1a, 1b, 1c,... In each row is adjusted around the main rotation axis X.

  On the other hand, each row of mirror segments 1a, 1b, 1c,... Is attached to each of the individual axes Y1, Y2, Y3,. Rotation is individually controlled by 4a, 4b, 4c,..., And the rotation angle is individually adjusted in the north-south direction (row direction) about each individual axis Y1, Y2, Y3,.

  As described above, the procedure for adjusting the rotation angle of the heliostat 1 installed on the reflection line L1 has been described on behalf of the reflection lines in each row, but it is installed on the other reflection lines L2, L3,. The same applies to the heliostat 1 (mirror segments 1a, 1b, 1c,...).

  The mirror segments 1a, 1b, 1c,... In each row are set to a standard module in which, for example, the reflection line direction (north-south direction) is 1 m in length and the horizontal direction (east-west direction) is 2 m. . FIG. 1 shows, as an example, five mirror segments 1a, 1b, 1c,... 1e arranged in series as shown in FIG. An example in which two sets of units are arranged in series on the lines L1, L2,. However, the number of mirror segments constituting one set is not limited to five, and the number of units arranged in each reflection line is not limited to two.

  In addition, the length of the reflection line on the north side and the south side is not necessarily the same with respect to the light receiving line installed in the east-west direction. In the northern hemisphere, the solar trajectory passes to the south side with respect to the light receiving line. When installing in the northern hemisphere, the length of the reflection line is made longer to the north side than the south side, and the mirror installation area on the north side is made larger, thereby improving the light collection and heat collection efficiency. On the other hand, when installing in the southern hemisphere, contrary to the case of installing in the northern hemisphere, the light collection and heat collection efficiency can be increased by making the length of the reflection line longer to the south side than the north side.

  Further, in the plurality of reflection lines, the land-occupying area where the reflection lines are installed can be made longer in the row direction (north-south direction) than in the column direction (east-west direction). As described above, the receiver is installed in the east-west direction and the angle of the mirror segment is adjusted to irradiate the light receiving line. Therefore, by extending the reflection line in the row direction (north-south direction), the conventional linear A condensing optical system with less light loss than a Fresnel type solar condensing device can be obtained. Thus, by configuring the mirror segment extended in the north-south direction, loss can be reduced and high heat collection energy can be obtained. In addition, since the receiver in the east-west direction can be set shorter than the conventional linear Fresnel solar concentrator, heat loss due to re-radiation of absorbed heat can be reduced.

<Receiver configuration>
FIG. 4 is a cross-sectional view showing the configuration of the receiver in FIG. As shown in the figure, the receiver 2 has a plurality of heat collecting pipes (stainless steel pipes, etc.) 6, 6,. In addition, the heliostat is arranged over the entire row of the heliostat (here, the reflection lines L1 to L8), and one end thereof is connected to the heat supply source 5 shown in FIG. The heat collecting pipe 6 receives the reflected light from the heliostat 1, collects the heat medium heated by the reflected heat, and supplies it to the heat supply source 5.

  Further, the heat collecting pipe 6 is covered with a heat insulating outer wall 7 above the heat collecting pipe 6, and a heat absorbing net 8 having a cavity window function is set immediately below the row of the heat collecting pipe 6. The heat insulating outer wall 7 is a cover having an arcuate cross section, and includes a set of heat collecting pipes 6, 6,... Arranged in parallel, and its lower surface is closed by a heat absorbing net 8. By projecting both edges of the heat insulating outer wall 7 downward from the end edges of the heat absorbing net 8, convective heat loss due to the rising air flow in the heat insulating outer wall 7 can be considerably suppressed.

  The endothermic net 8 is a stainless mesh having a constant thickness such as a girder or a honeycomb structure, and the reflected light from the heliostat passes through the mesh wall and reaches the inside, but the emitted light is transmitted from the inside of the mesh. The structure is difficult to come out.

<Irradiation area on the light receiving line>
FIG. 5 is a view for explaining an irradiation region on the light receiving line in FIG.
Over the entire length of the heat collecting pipe 6 constituting the receiver 2, it is divided into an irradiation region and a non-irradiation region alternately at a constant interval, and the mirror segments 1a, 1b,. It is desirable to increase the efficiency of heat transfer to the fluid in the heat collecting pipe by irradiating the reflected light from

  FIG. 5A is an example in which five irradiation areas F1 to F5 are set within the entire length of the heat collecting pipe 6 (length P1) provided in the receiver 2 on the light receiving line G. Between each irradiation area | region F1-F5, the non-irradiation area | region d of fixed length is ensured, and irradiation area | region F1-F5 is disperse | distributed substantially uniformly over the substantially full length of the length P1 of the heat collecting pipe 6. FIG. ing.

  For each of the irradiation regions F1 to F5, the reflected light applied to the mirror segments 1a, 1b,... Of each reflection line is applied to the heat collecting pipe 6, and the heat medium in the heat collecting pipe 6 is heated. The heat medium heated in each of the irradiation regions F1 to F5 with the irradiation region F1 as the start end and the irradiation region F5 as the end is sent out from the end irradiation region F5 toward the heat supply source 5 shown in FIG. Further, when the non-irradiated region d is insulated, heat radiation from this portion to the outside is suppressed, and the fluid in the heat collecting pipe 6 can be heated to a higher temperature and sent out toward the heat supply source 5. is there.

  FIG. 5B is a graph showing a temperature distribution T1 of the fluid with respect to the heat collecting pipe (length P1) when the non-irradiated region d is insulated. For comparison, the fluid temperature distribution T2 is as shown in FIG. 5C when the reflected light is concentrated on a specific area of the heat collecting pipe without securing non-irradiation areas on both sides of the irradiation areas F1 to F5. It is a temperature distribution curve of a fluid. As apparent from the comparison of the two temperature distributions, T1> T2.

  Thus, when each irradiation area F1-F5 is heated by arrange | positioning the non-irradiation area | region d at the both ends of each irradiation area | region F1-F5, each irradiation area | region F1-F5 of each heat collection pipe 6 is each from each irradiation area | region F1-F5. Heat was transferred to the non-irradiation region d at both ends of the irradiation region, and in addition to direct heat transfer from the irradiation region to the fluid inside the heat collecting pipe, heat transfer from the non-irradiation region d to the fluid occurred and was heated to a high temperature. The contact time between the heat collecting pipe 6 and the fluid is increased, and as a result, the amount of heat transferred from the heat collecting pipe 6 to the internal fluid is increased, and the high temperature fluid can be sent to the heat supply source 5. In addition, the length of each non-irradiation area | region d between each irradiation area | region F1-F5 and each irradiation area | region F1-F5 is not restrict | limited, Each irradiation area | region F1- is within the full length range of the heat collecting pipe 6 (length P1). F5 can be freely set equally or unevenly.

  In FIG. 1, the mirror segments 1a, 1b,... Arranged on the respective reflection lines L1, L2, L3... Are controlled in rotation angle for each column in the east-west direction, and individually in the north-south direction. The rotation angle is controlled, and the rotation angles are adjusted in the north-south direction and the east-west direction, respectively, to receive direct light from the sun and irradiate the reflected light toward the upper receiver 2.

  Reflected light from the mirror segments 1a, 1b,... In each column and each row passes through the heat absorbing network 8 of the receiver 2 into the space surrounded by the heat insulating outer wall 7, and fills the inside through the heat collecting pipe 6. The heated heat medium is heated and repeatedly heated to a high temperature while passing through the heat collecting pipe 6 and sent to the heat supply source 5. In the heat supply source 5, for example, high-temperature steam is generated and used for steam turbine power generation, or processed into chemical energy fuel by an endothermic chemical reaction.

  In the linear solar light collecting apparatus described above, an example in which the intervals between the mirror segments arranged along the reflection lines L1, L2,... Are arranged at regular intervals regardless of the distance to the receiver 2 is shown. It was.

  However, at a position close to the receiver 2, light loss due to blocking between the front and rear mirror segments on the light receiving line, that is, between adjacent mirror segments on the light receiving line is small, but the front and rear are increased as the distance from the receiver 2 increases. Light loss due to blocking between mirror segments increases. In order to prevent light loss such as blocking between the front and rear mirror segments, it is desirable to set the front and rear intervals in the column direction of the mirror segments to be narrower on the side closer to the light receiving line and wider as the distance from the light receiving line increases.

  The farther away from the position of the light receiving line G, the more the reflected light is blocked. Therefore, the distance between the front and rear mirror segments arranged on the north and south sides of the position of the light receiving line G where the receiver 2 is installed is changed. It is desirable to secure space. However, it is not always necessary to change the interval between the front and rear mirror segments, and it can be dealt with by dividing into several zones in order from the position closest to the light receiving line G and changing the number of mirror segments included in each zone. .

  As described above, according to the linear sunlight collecting apparatus shown in FIG. 1, the receiver 2 is installed on the light receiving line G set in the east-west direction, and the angle of the mirror segments 1a, 1b,. However, since the light receiving line G is irradiated with sunlight received by the mirror segments 1a, 1b,..., The angle adjustment of the mirror segments 1a, 1b,. The amount is as small as a few degrees a day or less, even over a year, a few dozen degrees or less (about 1/2 of the ground axis inclination of 23.4 degrees), and the optical loss due to mirror angle fluctuation is very small.

  In addition, the angle adjustment in the east-west direction of the mirror segments 1a, 1b,... Suffices to collect light along the line of the light receiving line. Compared to small cosine loss. Further, since the fluctuation of light loss is small even with respect to the change in solar altitude of the day, the fluctuation of heat collection energy of the day can be suppressed to a small level.

Next, the basic configuration of the linear solar light collecting apparatus according to the embodiment of the present invention will be described in more detail and specifically.
<Example of mirror segment arrangement>
FIG. 6 is a diagram showing an example of arrangement of mirror segments in FIG.
Here, the length of the reflection line is 210 m, and the receiver 2 is installed with the center 20 m in height as the light receiving line G. Further, the range of 105 m before and after the position of the light receiving line G in the reflection line was divided into three equal parts, and was divided into a D1 zone, a D2 zone, and a D3 zone in order of 35 m from the position closest to the light receiving line G. Furthermore, the number of mirror segments in each zone was 34 in the D1 zone, 30 in the D2 zone, 26 in the D3 zone, and the receiver width was set to 0.5 m to receive sunlight. As a result, the receiver input heat of sunshine intensity 0.8 kW / ^{m 2} was about 400 kW / ^{m 2.}

70 lines were arranged, and 20 pipes into which air gas at room temperature was injected at 10 atm from one end (inlet) of the receiver were arranged in the receiver. By setting the air flow rate to approximately 2.5 m ² / sec, the air temperature at the receiver outlet after passing through the 70 lines could be heated to approximately 700 ° C. At this time, the collection energy 400 kW / m ² at the receiver inlet is 5 to 10 times that of a normal linear Fresnel collection system. Further, the total light collecting power of the 70 lines was 25 MW.

<Structural model and condensing simulation of linear solar concentrator>
Next, the result of the light collection simulation of the structural model of the linear solar light collecting apparatus shown in FIG. 1 and the structural model of the preceding example will be described.

  7 is a diagram showing an example of the structural model of the linear solar light collecting device shown in FIG. 1, FIG. 8 is a top view showing another example of the structural model of the linear solar light collecting device shown in FIG. 9 is a diagram showing a structural model of the preceding example 1, and FIG. 10 is a diagram showing a structural model of the preceding example 2. 7A, 7B, and 7C are a top view, a front view (viewed from the east side), and a side view (viewed from the south side), respectively. The same applies to FIGS. 9A, 9B, 9C, 10A, 10B, and 10C.

  In the structural model shown in FIG. 7 (hereinafter referred to as Example 1), as described with reference to FIG. 1, the eight reflection lines L1 to L8 are arranged in the north-south direction, and the eight reflection lines L1 to L8 are arranged. One light receiving line G is arranged in the east-west direction above them so as to cross three-dimensionally. Further, the number of mirror segments on the north side and the south side of the light receiving line G is the same number (four each). Here, the angle of the mirror surface of each reflection line is controlled so that the reflected light always enters the light receiving line perpendicularly.

  In the structural model shown in FIG. 8 (hereinafter referred to as Example 2), as in Example 1 shown in FIG. 7, eight reflection lines L1 to L8 are arranged in the north-south direction, and eight reflection lines L1 to L8 are arranged. One light receiving line G is arranged in the east-west direction above them so as to cross three-dimensionally. However, in the first embodiment, the number of mirror segments on the north side and the south side of the light receiving line G is the same (four each), whereas in the second embodiment, the mirror segments 1a, 1b,. Are arranged more asymmetrically on the north side than on the south side (north side 7 with respect to south side 1), and the row direction (north-south direction) is the column direction (east-west direction) in the area where the reflection lines L1, L2,. Set longer than. As in FIG. 7, in this case as well, the angle of the mirror surface of each reflection line is controlled so that the reflected light always enters the light receiving line perpendicularly.

  In the structural model of the first example shown in FIG. 9, eight reflection lines L1 to L8 are arranged in the north-south direction, and one receiver R is arranged in the north-south direction above the reflection line.

  In the structural model of Prior Example 2 shown in FIG. 10, eight reflection lines L1 to L8 are arranged in the east-west direction, and one receiver R is arranged in the east-west direction above the reflection lines.

  FIG. 11 shows a graph simulating a daily change in irradiation energy on the receiver of each structural model shown in FIGS. The simulation date, place, and simulation setting conditions are as follows.

・ Date: Equinox (2011/3/21)
・ Location: Armenia, Spain (latitude: 36.84 ° north / longitude: 2.47 ° west)
-Total area of mirror segment: 64m ²
・ Receiver length: 11m
・ Receiver height: 5m from the ground surface

  As shown in FIG. 11, it can be seen that the irradiation energy amount of Examples 1 and 2 is large as a whole although the irradiation energy amount of the preceding example 1 is a little larger during a short morning and evening time. Further, when the mirror segments 1a, 1b,... Are made asymmetrical according to the latitude, for example, when the mirror segments 1a, 1b,. It can be seen that by increasing the number of mirrors on the north side and increasing the south side in the case of the southern latitude (southern hemisphere), the cosine loss can be reduced for each mirror, and the irradiation energy can be increased.

<Solar condensing power generation system using linear solar concentrator>
By combining the linear solar light collecting device shown in FIG. 1 with a solar light collecting device having a high heat collecting ability as a relay, the preheated fluid can be heated to a higher temperature.

  FIG. 12 shows an example in which four linear solar light collecting devices 10 a to 10 d are used as a relay of the tower type light collecting device 11. According to this combination, the fluid temperature preheated to 300 ° C. can be increased to 600 ° C. by dispersing and heating the fluid in four linear solar light collectors 10a to 10d, and each linear solar light collector can be heated. The fluid heated by the optical devices 10a to 10d was heated by the condensed heat obtained in the tower type light collecting device 11, and finally a high temperature fluid of 800 ° C. was obtained.

  On the other hand, in a system that collects and collects heat from the tower-type concentrator 11 at a stretch, for example, in order to realize a plant with a heat collection amount of 100 MW, the tower height exceeds 100 m, and the heliostat field is also It extends over several kilometers. Therefore, the construction cost is enormous and it is difficult to supply power at a low cost.

  Therefore, the linear solar light collecting device as shown in FIG. 1 is used as the preheating means, and after preheating to a temperature lower than the target temperature, for example, about 600 ° C., the main heating means has a higher temperature than the linear solar light collecting device. The temperature is raised to a target temperature, for example, around 800 ° C., using another type of solar light collecting device suitable for condensing, for example, a tower-type solar light collecting device.

  As described above, the linear solar light collecting device as shown in FIG. 1 is used for a repeater, and the temperature is raised in two stages, thereby reducing heat collection energy loss such as re-radiation and reducing construction cost and land area. A solar concentrating power generation system can be realized.

  The basic configuration of the linear solar light collecting apparatus according to the embodiment of the present invention has been described above. Next, the linear sunlight condensing device of embodiment of this invention is demonstrated. Embodiments of the present invention include the first to fourth embodiments, all of which improve the above-described linear sunlight condensing device and increase the condensing ratio in the light receiving line to increase the heating efficiency. .

Therefore, the concentration ratio will be described before describing each embodiment.
In a solar concentrating power generation system that collects sunlight and overheats the heat medium for power generation, the heat collection efficiency (ηth) is the amount of energy (heat amount) Qout [W] obtained by the heat medium in the receiver. It is known that the value divided by Qin [W] is expressed by the following formula [1] (“New Solar Energy Utilization Handbook”, New Solar Energy Utilization Handbook Editorial Committee, published by the Japan Solar Energy Society, 2010-05-01 (4.7.14 formula)).
ηth = Qout / Qin (1)

The amount of energy Qout obtained by the heat medium is derived from the energy obtained by the heat medium and heat loss (considering only radiation loss), and is expressed by the following equation [2].
Qout = Ib.Aa..eta.opt..alpha.-Ar..epsilon..sigma. (Tr ⁴ -Ta ⁴ ) (2)

Here, Ib: solar radiation amount [W / m ² ], Aa: mirror opening area [m ² ], ηopt: light collection efficiency, α: receiver heat absorption rate, Ar: receiver light collection area [m ² ], ε : Thermal emissivity of receiver surface, σ: Stefan-Boltzmann constant [W / m ² · K ⁴ ], Tr: receiver temperature [K], Ta: ambient temperature [K].

On the other hand, the solar radiation amount Qin is represented by the following formula [3].
Qin = Ib · Aa (3)

Substituting equations [2] and [3] into equation [1] yields equation [4] below.
ηth = ηopt · α-ε · σ · (Tr ⁴ −Ta ⁴ ) / (Ib · X) Equation (4)
Here, X (= Aa / Ar) is called a condensing ratio.

When the maximum temperature Tr, max of the receiver is obtained from the equation [4], the following equation [5] is obtained.
Tr, max ⁴ = X · Ib · ηopt · α / (ε · σ) + Ta ⁴ Equation [5]

  That is, in order to increase the temperature of the heat medium, it is necessary to increase the concentration ratio X. Therefore, in this embodiment, by independently adjusting the angle of the mirror segment on the heliostat installed in the reflection line, the position (light receiving position) where the reflected light in each mirror segment reaches the east-west direction of the receiver is determined. It was adjusted so that the light collection ratio at an arbitrary position in the east-west direction of the receiver can be set freely.

[First Embodiment]
FIG. 13 is a diagram showing a structural model of the linear solar light collecting apparatus according to the first embodiment of the present invention. In this figure, the same reference numerals as in FIG. 7 are assigned to the same or corresponding parts as in FIG. Here, FIGS. 13A and 13B are a top view and a side view, respectively.

  As shown in FIG. 13B, the linear solar light collecting apparatus of the present embodiment collects reflected light from every two reflection lines adjacent in the east-west direction in one irradiation region (light receiving position) of the receiver 2. The light collection ratio X in the irradiation region is doubled. This configuration corresponds to doubling the mirror aperture area Aa without changing the receiver condensing area Ar.

  That is, compared with the linear sunlight condensing device shown in FIG. 7, the interval between the irradiation regions is doubled, but when the non-irradiation region is insulated, the heat radiation from that portion is suppressed and heated to a higher temperature. be able to.

[Second Embodiment]
FIG. 14 is a diagram showing a structural model of the linear solar light collecting apparatus according to the second embodiment of the present invention. In this figure, the same reference numerals as in FIG. 13 are assigned to the same or corresponding parts as in FIG. Here, FIGS. 14A and 14B are a top view and a side view, respectively.

  In this embodiment, as the heat supply source (west side) is approached, the light collection ratio in the irradiation region is increased. That is, the reflected lights from the first and second reflection lines L8 and L7 counted from the east side are condensed in different irradiation areas, and the reflected lights from the third and fourth reflection lines L6 and L5 are shared by a common 1 The light is condensed on one irradiation region, and the reflected light from the fifth to eighth reflection lines L4 to L1 is condensed on one common irradiation region.

  In this way, the heat supply source is set to a higher temperature than in the first embodiment by freely setting the light collection ratio at an arbitrary position of the receiver 2 in accordance with the temperature required for the heat supply source. Can do.

[Third Embodiment]
FIG. 15 is a diagram showing a structural model of a linear solar light collecting apparatus according to the third embodiment of the present invention. In this figure, the same reference numerals as in FIG. 13 are assigned to the same or corresponding parts as in FIG. Here, FIGS. 15A and 15B are a top view and a side view, respectively.

  Similarly to the second embodiment, this embodiment is configured such that the light collection ratio in the irradiation region increases as the heat supply source (west side) is approached. The difference from the second embodiment is that the concentration of light is gradually increased in the second embodiment, whereas it is increased stepwise in the present embodiment.

  In the present embodiment, the reflected lights from the first to fourth reflection lines L8 to L5 counted from the east side are collected in different irradiation areas, and the reflected lights from the fifth and sixth reflection lines L4 and L3 are collected. The light is condensed on one common irradiation area, and the reflected light from the seventh and eighth reflection lines L2 and L1 is condensed on one common irradiation area. Also in this embodiment, the same effect as the second embodiment can be obtained.

[Fourth Embodiment]
FIG. 16 is a side view of a structural model of a linear solar light collecting apparatus according to the fourth embodiment of the present invention. In this figure, the same reference numerals as in FIG. 13 are assigned to the same or corresponding parts as in FIG.

  In the present embodiment, a curvature is given in the east-west direction of the reflection surface of each mirror segment constituting the heliostat installed in each reflection line L1 to L8, that is, the reflection surface is configured by a curved surface. This configuration means that the condensing ratio X is increased by reducing the receiver condensing area Ar without changing the mirror aperture area Aa. The cross-sectional shape of the curved surface may be anything as long as it is a curve such as a circle, an ellipse, or a parabola. In particular, when a cylindrical parabola shape with a heat collecting pipe as a focal line is used, the spread of reflected light can be suppressed compared to a planar shape, so more light is irradiated to the heat collecting pipe. It becomes possible.

[Fifth Embodiment]
FIG. 17 is a diagram illustrating a structural model of a linear solar light collecting apparatus according to the fifth embodiment of the present invention, and FIG. 18 is a diagram illustrating a main configuration of the receiver 21. Here, FIGS. 17A, 17B, and 17C are a top view, a front view, and a side view, respectively. In this figure, the same reference numerals as those in FIG. 7 are assigned to the same or corresponding parts as those in FIG.

  In the present embodiment, a receiver 21 shown in FIG. 18 is used instead of the receiver 2 in FIG. The receiver 21 includes a compound parabolic concentrator 77.

In FIG. 18, the radius of the heat collecting pipe 6 is a, the longitudinal direction of the heat collecting pipe 6 is the z axis (not shown), the negative direction of the y axis is the zenith direction, and the central axis coordinate of the heat collecting pipe 6 is x = 0. When y = 0 and the maximum incident angle of the compound parabolic condenser mirror 77 is θ ₁ , the cross-sectional shape of the compound parabolic condenser mirror 77, that is, the xy coordinates of the surface of the compound parabolic condenser mirror 77 is It is represented by the following formulas [6] to [9].

For “0 ≦ θ ≦ (π / 2) + θ ₁ ” x = ± a {sin θ + θ cos (θ−π)} Equation [6]
y = a {−cos θ + θ sin (θ−π)} (7)
For “(π / 2) + θ ₁ ≦ θ ≦ (3π / 2) −θ ₁ ” x = ± a {sin θ + pcos (θ−π)} Equation [8]
y = a {−cos θ + psin (θ−π)} (9)
However,
p = {θ + θ ₁ + (π / 2) cos (θ−θ ₁ )} / {1 + sin (θ−θ ₁ )}
It is.

  By determining x and y in this way, the spread of the reflected light can be minimized and more heat can be applied to the heat collecting pipe 6. Since the derivation process of this equation is described in the following documents 1 and 2, description thereof is omitted.

<Reference 1>
"High Collection Nonimaging Optics", pp.263-266, First
Edition edition, December 1989
Author: WTWelford, R. Winston
Publisher: Academic Pr
ISBN-10: 0127428852
ISBN-13: 978-0127428857

<Reference 2>
"Dyna", year77, Nro.163, pp.132-140, Medellin, September
2010, ISSN0012-7353
"MODELING OF DIRECT SOLAR RADIATION IN A COMPOUND PARABOLIC COLLECTOR (CPC) WITH THE RAY TRACKING TECHNIQUE"
Section 3.1 (page 134) of this document describes the above formula. T in this description, .theta.a is, theta in the above equation correspond to the theta _1.

[Sixth Embodiment]
FIG. 19 is a front view of a structural model of a linear solar light collecting apparatus according to the sixth embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 17 are attached to the same or corresponding parts as those in FIG.

  The present embodiment includes a receiver 21 as in the fifth embodiment. The difference from the fifth embodiment is that, in the fifth embodiment, the number of mirror segments on the north side and the south side of the light receiving line G is the same, but in this embodiment, as in FIG. doing.

In addition, the center of the opening of the compound parabolic condensing mirror 77 is changed in accordance with the fact that it is arranged more on the north side than on the south side. That is, in the fifth embodiment, it is directed downward in the vertical direction, but in this embodiment, the angle θ ₂ defined by the following equations [10] and [11] is inclined from the vertical downward direction.

In this equation, m: n is a ratio (m <n) between the number of mirror segments arranged on the south side and the number of mirror segments arranged on the north side. By tilting the angle in this way by θ ₂ , the amount of light incident on the composite paraboloidal collector mirror 77 can be maximized on an average annual basis, and the amount of light irradiated on the heat collecting pipe 6 can be maximized.

Here, equation [10] is calculated using the cosine theorem and the three-square theorem.
That is, in “a ² = b ² + c ² −2bccosA” which is an expression of the cosine theorem, “a ² = L ² ”, “b ² = H ² + {m / (m + n) * L} ² ”, “c ² = H ² + {n / (m + n) * L} ² ”,“ A = 2θ ₁ ”. Equation [10] is derived from tangents in two right triangles whose apex angles are θ ₁ −θ ₂ and θ ₁ + θ ₂ , respectively.

[Seventh Embodiment]
FIG. 20 is a diagram showing a structural model of a linear solar light collecting apparatus according to the seventh embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 17 are attached to the same or corresponding parts as those in FIG.

  In this embodiment, the receiver 21 shown in FIG. 18 is used in place of the receiver 2 in the first embodiment (FIG. 13). According to this embodiment, in addition to the effect of 1st Embodiment, the effect of 5th Embodiment is acquired.

[Eighth Embodiment]
FIG. 21 is a diagram showing a structural model of a linear solar light collecting apparatus according to the eighth embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 17 are attached to the same or corresponding parts as those in FIG.

  This embodiment uses a receiver 21 shown in FIG. 18 in place of the receiver 2 in the second embodiment (FIG. 14). According to this embodiment, the effect of the fifth embodiment can be obtained in addition to the effect of the second embodiment.

[Ninth Embodiment]
FIG. 22 is a diagram showing a structural model of a linear solar light collecting apparatus according to the ninth embodiment of the present invention. In this figure, the same reference numerals as those in FIG. 17 are attached to the same or corresponding parts as those in FIG.

  This embodiment uses a receiver 21 shown in FIG. 18 in place of the receiver 2 in the third embodiment (FIG. 15). According to the present embodiment, in addition to the effects of the third embodiment, the effects of the fifth embodiment can be obtained.

The present invention can be modified as shown in the following (1) and (2).
(1) The condensing ratio is changed according to the time zone. For example, the irradiation energy loss due to cosine loss and shadowing is large in the morning and evening, while the irradiation energy loss is small in the middle and south, so the temperature required for the heat supply source can be changed by changing the concentration ratio according to the time zone. It is possible to stably produce a heat medium.
(2) The position of the heat insulating member that insulates the non-irradiation region is changed according to the position of the irradiation region irradiated with the reflected light from the mirror segment. Thereby, even if a non-irradiation area changes with a change in the light collection ratio, the heat insulating member can be moved to an appropriate position, so that heat loss can be reduced.

  L1 to L8 ... reflective line, G ... light receiving line, Z ... heat receiving zone, 1 ... heliostat, 1a, 1b, 1c, ... mirror segment, 2, 21 ... receiver, 3 ... column direction drive device, 4a, 4b,... Row driving device, 5 ... heat supply source, 6 ... heat collecting pipe, 7 ... heat insulating outer wall, 8 ... heat absorption network, 77 ... compound parabolic condensing mirror.

US2009 / 0056703 A1: Applicant Ausra Inc. “LINEAR FRESNEL SOLAR ARRAYS AND COMPONENTS THEREFOR” US2010 / 0012112 A1: Applicant AUSRA PTY LIMITED, “ENERGY COLLECTOR SYSTEM HAVING EAST-WEST EXTENDING LINEARREFLECTORS”

Solar 2004: Life, the Universe and Renewables “Steam-circuit Model for the compact Linear Fresnel Reflector Prototype”

Claims (13)

A linear solar light collecting device having a plurality of reflection lines and one light receiving line,
The reflection lines are set in parallel in the north-south direction,
The light receiving line is set in the east-west direction above the reflection line,
Each reflection line is equipped with a heliostat consisting of multiple mirror segments,
In the light receiving line, one receiver that receives reflected heat of sunlight irradiated from the heliostat and collects heat is installed,
Angle adjustment means capable of individually adjusting the angles of the mirror segments, and by combining the light receiving areas on the receiver of reflected light from a plurality of reflection lines adjacent in the east-west direction by the angle adjustment means, A linear solar concentrator capable of adjusting the concentration ratio in the area. The receiver has a heat collecting pipe filled with a heat medium inside,
The linear solar light collector according to claim 1, wherein the heat collecting pipe is divided into an irradiation region irradiated with reflected light from the mirror segment and a non-irradiation region disposed at both ends thereof. .   The linear solar light collector according to claim 2, wherein the irradiation region is a region that is heated by reflected light to transfer heat from the irradiation region to the non-irradiation region, and causes heat transfer to the fluid in the heat collection pipe.   The linear sunlight condensing device according to claim 1, wherein the angle adjusting unit is capable of adjusting a rotation angle in a north-south direction and an east-west direction.   The linear sunlight condensing device according to claim 1, wherein a reflection surface of the mirror segment is a curved surface.   The linear sunlight condensing device according to claim 4, wherein the angle adjusting unit adjusts the rotation angle in the east-west direction in common and individually adjusts the rotation angle in the north-south direction.   The mirror segment is set to a regular module whose length in the north-south direction is twice as long as the length in the east-west direction, and a set of several mirror segments arranged in series. The linear solar light collecting device according to claim 1, wherein the linear solar light collecting device is arranged so as to face each other on the reflection line.   The distance between the mirror segments in the north-south direction is set wider as the distance from the light receiving line increases, and is an interval for reducing light loss such as blocking and shadowing between mirror segments adjacent in the north-south direction. Linear solar concentrator.   When installed in the Northern Hemisphere, the length of the reflective line with the light receiving line as the boundary is set longer than the south side, and when installed in the Southern Hemisphere, the length of the reflective line with the light receiving line as the boundary. The linear solar light collecting device according to claim 1, wherein is set longer on the south side than on the north side. The receiver has a heat collecting pipe filled with a heat medium inside, and is disposed above the entire row of heliostats, one end of which is connected to a heat supply source,
The linear solar light collecting device according to claim 1, wherein the heat collecting pipe receives reflected light from a heliostat and collects a heated heat medium. The receiver has a plurality of heat collecting pipes in parallel, an upper part of the row of the heat collecting pipes is covered with a heat insulating outer wall, and a heat absorption network having a cavity window function is installed immediately below the row of the heat collecting pipes. ,
The heat insulating outer wall is a cover having a circular arc cross section, and includes a set of heat collecting pipes arranged in parallel,
Both edges of the heat insulating outer wall protrude downward from the edge of the heat absorption net,
The endothermic network is a stainless steel mesh having a constant girder or honeycomb structure, and the reflected light from the heliostat passes through the mesh and reaches the inside, but the emitted light is transmitted from the inside of the mesh. The linear solar light collecting device according to claim 1, wherein the linear solar light collecting device has a structure that is difficult to come out.   The linear solar light collecting apparatus according to claim 1, wherein the receiver has a compound parabolic condensing mirror that irradiates the heat collecting pipe after further reflecting reflected light from the mirror segment. A solar condensing system having a preheating means and a main heating means,
The preliminary heating means is means for heating to a first temperature lower than a target temperature using the linear solar light collecting device according to claim 1,
The main heating means is a means for raising the temperature to a second temperature, which is a target temperature, by using another type of solar light collecting device suitable for high-temperature heat collecting light than the linear solar light collecting device. Light concentrating power generation system.

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